Geomagnetic Activity Archive

December 2003
Monday, December 1: The geomagnetic field was at predominantly quiet to unsettled levels. High latitudes experienced periods of active conditions due to a weak recurrent high speed stream coronal hole. Solar wind speed ranged between 387 and 495 km/s, the planetary A index was 10.
Tuesday, December 2: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 374 and 469 km/s, the planetary A index was 9.
Wednesday, December 3: The geomagnetic field was at quiet to slightly unsettled levels. Solar wind speed ranged between 343 and 434 km/s, the planetary A index was 7.
Thursday, December 4: The geomagnetic field was at quiet to unsettled levels. Solar wind speed and the total field of the interplanetary magnetic field increased slowly after 12h UTC as a fairly low speed coronal stream began to dominate the solar wind. This coronal hole related stream increased in intensity after 02h UTC on December 5 with the IMF swinging strongly southwards. Solar wind speed ranged between 327 and 379 km/s, the planetary A index was 9.
Friday, December 5: The geomagnetic field ranged from quiet to major storm levels. A ten hour period of southward Bz, together with solar wind speed near 475 km/s produced minor storm levels for most of the day. At approximately 02:00 UTC the total field measurement of the interplanetary magnetic field (IMF) increased to 20 nT. The Bz component of the IMF, after an initial northward direction, turned southward for nearly ten hours, then began a north-south oscillation. This signature is similar to that of a co-rotating interaction region preceding the onset of a high speed stream, but may include transient effects from a faint halo CME that occurred on December 2. Solar wind speed ranged between 348 and 526 km/s, the planetary A index was 43.
Monday, December 8: The geomagnetic field varied from quiet to major storm levels. Solar wind speed ranged between 433 and 662 km/s, increasingly under the influence of a high speed coronal stream. The planetary A index was 39.
Tuesday, December 9: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 580 and 762 km/s under the influence of a high speed coronal stream. The planetary A index was 31.
Wednesday, December 10: The geomagnetic field was at active to major storm levels. Solar wind speed ranged between 586 and 879 km/s under the influence of a high speed coronal stream. The planetary A index was 42.
Thursday, December 11: The geomagnetic field has been at unsettled to major storm conditions. Solar wind speed ranged between 718 and 860 km/s under the influence of a high speed coronal stream. The planetary A index was 40.
Friday, December 12: The geomagnetic field has been at unsettled to minor storm levels. Solar wind speed ranged between 647 and 817 km/s under the influence of a high speed coronal stream. The planetary A index was 23.
Saturday, December 13: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 619 and 853 km/s under the influence of a high speed coronal stream. The planetary A index was 28.
Sunday, December 14: The geomagnetic field has been at unsettled to minor storm levels. Solar wind speed ranged between 631 and 862 km/s under the influence of a high speed coronal stream. The planetary A index was 25.
Wednesday, December 17: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 407 and 497 km/s, the planetary A index was 10.
Friday, December 19: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 292 and 353 km/s, the planetary A index was 7.
Saturday, December 20: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 304 and 490 km/s, generally increasing all day under the influence of a high speed coronal stream. The planetary A index was 16.
Tuesday, December 23: The geomagnetic field was quiet to unsettled. The coronal hole high speed stream has now rotated out of a geoeffective position. Solar wind speed declined from a maximum of near 650 km/s to approximately 500 km/s at the end of this period.

November 2003
Saturday, November 1: The geomagnetic field was at unsettled to minor storm levels. Solar wind speeds have gradually decreased from the start of the period, approximately 850 km/s to 600 km/s (at the time of this writing: 21.00 UTC) while the Bz component of the interplanetary magnetic field has remained consistently northward during the period.
Sunday, November 2: The geomagnetic field was at unsettled to minor storm levels. Isolated minor storm conditions were likely due to the continued elevated solar winds speeds and the occasional southward Bz in the interplanetary magnetic field. Solar wind speed ranged between 469 and 624 km/s, the planetary A index was 18.
Monday, November 3: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 464 and 568 km/s, the planetary A index was 10.
Tuesday, November 4: The geomagnetic field was at quiet to severe storm levels. A shock passage occurred at the ACE satellite near 06:00 UTC due to the CME from the X8 event on November 2. A sudden impulse of 72 nT was observed by the Boulder magnetometer at 06:27 UTC. The Bz component of the interplanetary magnetic field remained north though most of the day; however, an isolated period of severe storm conditions was observed from 09:00 to 12:00 UTC. Solar wind speed ranged between 461 and 697 km/s, the planetary A index was 31.
Wednesday, November 5: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 464 and 596 km/s, the planetary A index was 9.
Thursday, November 6: The geomagnetic field was at quiet to minor storm levels. The shock from the X28 flare on November reached Earth at 19:37 UTC. A 31nT sudden impulse was observed on the Boulder magnetometer and activity reached minor storm levels. The Bz component of the interplanetary magnetic field initially turned south to -7 nT and total field measurement reached 15 nT. Solar wind speed ranged between 440 and 592 km/s, The planetary A index was 14.
Friday, November 7: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 395 and 582 km/s, generally decreasing all day. The planetary A index was 8.
Thursday, November 8: The geomagnetic field was at quiet to unsettled levels. A fairly weak high speed stream arrived at about 13:00 UTC. While the interplanetary magnetic field has at times been moderately southwards, only a mild response has been observed on the geomagnetic field. Solar wind speed ranged between 408 and 502 km/s, the planetary A index was 10.
Saturday, November 9: The geomagnetic field was at quiet to major storm levels. An isolated major storm period occurred from 12:00-15:00 UTC. Solar wind speed ranged between 466 and 602 km/s under the influence of a high speed coronal stream. The planetary A index was 25.
Monday, November 10: The geomagnetic field was at quiet to major storm levels. An isolated major storm period occurred from 12:00-15:00 UTC. Solar wind speed ranged between 466 and 602 km/s under the influence of a high speed coronal stream. The planetary A index was 25.
Tuesday, November 11: The geomagnetic field ranged from active to severe storm levels. A single K=7 period was observed at Boulder from 03:00-06:00 UTC. Solar wind speed ranged between 596 and 776 km/s under the influence of a high speed coronal stream. The planetary A index was 51.
Wednesday, November 12: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 607 and 761 km/s under the influence of a high speed coronal stream. The planetary A index was 26.
Thursday, November 13: The geomagnetic field ranged from unsettled to minor storm levels, with a period of major storm levels at high latitudes. The interplanetary magnetic field became stronger after 11:00 UTC. Solar wind speed ranged between 581 and 759 km/s under the influence of a high speed coronal stream. The planetary A index was 42.
Friday, November 14: The geomagnetic field ranged from unsettled to major storm levels. Mostly minor storm levels predominated beginning at 21:00 UTC on November 13 through 15:00 UTC on November 14. Solar wind speed ranged between 569 and 719 km/s under the influence of a high speed coronal stream. The planetary A index was 37.
Monday, November 17: The geomagnetic field has been at active to minor storm levels. The favorably positioned coronal hole continued to cause high solar wind speeds, and the accompanying southward Bz of the interplanetary magnetic field, have kept the geomagnetic field activity at elevated levels throughout the period.
Tuesday, November 18: The geomagnetic field was at quiet to minor storm levels. Solar wind speed ranged between 610 and 761 km/s. The high speed stream appeared to be ending late in the day. The planetary A index was 20.
Wednesday, November 19: The geomagnetic field has been at quiet to active levels. Solar wind speed ranged between 451 and 646 km/s, the planetary A index was 14.
Thursday, November 20: The geomagnetic field was at quiet to extremely severe storm levels. A CME shock arrived at SOHO and was observed at 07:40 UTC, and a geomagnetic sudden impulse was observed at 08:05 UTC. A very strong (55 nT) southward component of the interplanetary magnetic field resulted in severe geomagnetic storming during the latter half of the day. Solar wind speed ranged between 431 and 915 km/s., the planetary A index was 117.
Friday, November 21: The geomagnetic field was at quiet to severe storm levels. Solar wind speed ranged between 446 and 581 km/s, the planetary A index was 39.
Saturday, November 22: The geomagnetic field has been at mostly quiet to unsettled levels.
Sunday, November 23: The geomagnetic field was at quiet to minor storm levels. Solar wind speed ranged between 466 and 601 km/s under the influence of a high speed coronal stream. The planetary A index was 21.
Monday, November 24: The geomagnetic field was quiet to unsettled with isolated active periods at higher latitudes. A well positioned coronal hole is producing solar wind speeds near 600 km/s, creating a weak disturbance in the geomagnetic field. Solar wind speed ranged between 462 and 615 km/s, the planetary A index was 12.
Tuesday, November 25: The geomagnetic field was quiet to unsettled with isolated active periods. The disturbed periods are due to a moderate high speed solar wind stream from a well positioned coronal hole. Solar wind speed ranged between 494 and 706 km/s, the planetary A index was 13.
Thursday, November 27: The geomagnetic field was quiet to unsettled on November 27. Solar wind speed ranged between 400 and 527 km/s, gradually decreasing all day. The planetary A index was 10.
Sunday, November 30: The geomagnetic field was at quiet to unsettled levels. Ace data indicated that a weak recurrent coronal hole high speed stream became geoeffective early in the period. Solar wind speed ranged between 365 and 544 km/s, the planetary A index was 10.

October 2003
Wednesday, October 1: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 276 and 326 km/s. A disturbance arrived at ACE at approximately 16:00 UTC. At first the interplanetary magnetic field was weakly southwards, then became moderately to strongly southwards between 19:00 and 21:00 UTC. After 21:00 UTC the IMF has been northwards. The planetary A index was 10.
Thursday, October 2: The geomagnetic field was at quiet to unsettled levels. The unusual disturbance which began on October 1 continued on October 2. Solar wind IMF signatures are consistent with a transient passage, but solar wind speed has remained quite low; consequently, geomagnetic field impact was minimal.The interplanetary magnetic field was northwards until about 20:00 UTC after which time increasingly more frequent and stronger southwards excursions have been observed. Solar wind speed ranged between 275 and 537 km/s, the planetary A index was 9.
Friday, October 3: The geomagnetic field was at mostly quiet to active levels with an isolated minor storm period between 03:00-06:00 UTC. Solar wind speed ranged between 465 and 572 km/s, the planetary A index was 16.
Saturday, October 4: The geomagnetic field was at quiet to slightly active levels. Solar wind speed ranged between 388 and 538 km/s, the planetary A index was 9.
Sunday, October 5: The geomagnetic field was at very quiet to active levels. A high speed coronal stream arrived at ACE at approximately 16:00 UTC. The interplanetary magnetic field (IMF) was moderately to strongly southwards at times between 19:00 and 21:00 UTC. Since then the IMF has been mostly northwards resulting in a significant decrease in the geomagnetic disturbance level. Solar wind speed ranged between 333 and 503 km/s, the planetary A index was 9.
Monday, October 6: The geomagnetic field was at quiet to unsettled levels. The Bz component of the IMF remained north throughout the majority of the day. The main part of the fairly weak high speed stream was observed at ACE after 11:00 UTC with solar wind speed peaking at 22:00 UTC. Solar wind speed ranged between 368 and 734 km/sec, the planetary A index was 10.
Tuesday, October 7: The geomagnetic field was at quiet to active levels. A recurrent coronal hole high speed stream is responsible for the elevated conditions. Solar wind speed ranged between 481 and 650 km/s, the planetary A index was 13.
Wednesday, October 8: The geomagnetic field was at quiet to unsettled levels. A slow increase in wind speed was noted between 04:00-17:00 UTC and the high speed stream intensified towards the end of the day. Solar wind speed ranged between 474 and
678 km/s, the planetary A index was 9.
Thursday, October 9: The geomagnetic field was mostly quiet with the exception of a single active interval early in the day. Solar wind speed ranged between 456 and 651 km/s under the influence of a high speed stream. This influence weakened through the day and appeared to be ending at 20:00 UTC at ACE. The planetary A index was 8.
Friday, October 10: The geomagnetic field was quiet. The interplanetary magnetic field was northwards most of the day, only a few brief and weak southwards excursions were observed. Solar wind speed ranged between 408 and 517 km/s, the planetary A index was 5.
Saturday, October 11: The geomagnetic field has been at quiet to unsettled levels. Solar wind speed ranged between 350 and 433 km/s, the planetary A index was 5.
Sunday, October 12: The geomagnetic field was at quiet to slightly unsettled levels. Solar wind speed ranged between 286 and 369 km/s, the planetary A index was 6.
Monday, October 13: The geomagnetic field has been at quiet to active levels. Solar wind speed ranged between 316 and 537 km/s, increasingly under the influence of a high speed coronal stream. The Bz ranged from +/- 10 nT, the planetary A index was 13.
Tuesday, October 14: The geomagnetic field was at unsettled to major storm levels. The elevated activity is a result of the continued rise in the solar wind velocity and sustained southward Bz. Solar wind speed ranged between 416 and 671 km/s, the planetary A index was 48.
Wednesday, October 15: The geomagnetic field was at unsettled to severe storm levels. These effects are the result of a coronal hole high speed stream. Solar wind speed ranged between 583 and 944 km/s, the planetary A index was 42.
Thursday, October 16: The geomagnetic field ranged from unsettled to minor storm levels. Solar wind data show the continuation of a high speed stream associated with a favorably positioned coronal hole. Solar wind speed ranged between 542 and 622 km/s, the planetary A index was 26.
Friday, October 17: The geomagnetic field ranged from quiet to minor storm levels. The earth continues to be under the influence of a high speed solar wind stream. The interplanetary magnetic field showed regular oscillations and had a weakly negative Bz component on average. Solar wind speed ranged between 488 and 583 km/s, the planetary A index was 31.
Saturday, October 18: The geomagnetic field ranged from unsettled to minor storm levels as the high speed solar wind stream continues. The interplanetary magnetic field Z-component fluctuated between -7 nT and + 5 nT but was weakly negative on average. Solar wind speed ranged between 479 and 588 km/s, the planetary A index was 27.
Sunday, October 19: The geomagnetic field ranged from unsettled to minor storm levels. A jump in solar wind velocity from 540 km/s to 600 km/s was observed around 22:00 UTC. However, the solar wind signatures continue to be consistent with a high speed coronal driven wind stream. The Bz component of the interplanetary magnetic field continues to oscillate around an average value of about -5 nT. Solar wind speed ranged between 532 and 658 km/s, the planetary A index was 32.
Monday, October 20: The geomagnetic field has been at unsettled to minor storm levels. Another favorably positioned coronal hole is perpetuating the high speed solar wind stream, and is continuing to keep the geomagnetic field disturbed. Solar wind speed ranged between 494 and 700 km/s, the planetary A index was 30.
Tuesday, October 21: The geomagnetic field has been at active to minor storm levels. A favorably positioned coronal hole is supporting a high speed solar wind stream, which is in turn supporting elevated magnetic activity at Earth. Solar wind speed ranged between 577 and 765 km/s, the planetary A index was 39.
Wednesday, October 22: The geomagnetic field ranged from quiet to major storm levels. The effects from a halo CME observed on October 19 dominated the solar wind all day, perhaps with the exception of the first few hours when some influence from a high speed coronal stream may still have been present. The interplanetary magnetic field has been northwards since 18:00 UTC and the geomagnetic field has consequently become quiet. Solar wind speed ranged between 467 and 773 km/s, the planetary A index was 33.
Thursday, October 23: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 375 and 584 km/s, generally decreasing all day. The interplanetary magnetic field was northwards all day. The planetary A index was 7.
Friday, October 24: The geomagnetic field has been at quiet to severe storm levels. A fairly strong solar wind shock was observed at SOHO at 14:47 UTC with a sudden increase in solar wind speed from 450 to 620 km/sec. The sudden impulse was followed by about two hours of severe geomagnetic storm activity, and produced a magnetopause crossing at the GOES 12 satellite. The total field of the interplanetary magnetic field (IMF) was impressively strong, however, having initially been moderately southwards, the IMF was mostly northwards after 18:00 UTC. This caused a decrease in the geomagnetic disturbance levels. Solar wind speed ranged between 384 and 658 km/s, the planetary A index was 34.
Saturday, October 25: The geomagnetic field has been quiet to active. Residual effects from yesterday's transient arrival continue to cause occasional active conditions. Solar wind speed has decreased steadily to about 500 km/s, and Bz continues to maintain a consistent northward orientation. Solar wind speed ranged between 441 and 615 km/s, the planetary A index was 14.
Sunday, October 26: The geomagnetic field has been quiet to active. Two solar wind shocks were recorded during the day. The first was observed at SOHO at 07:49 UTC, probably the arrival of a halo CME associated with a flare on October 23. The interplanetary magnetic field was continuously northwards after the arrival of this CME and therefore the CME did not become geoeffective. The second shock was noted at SOHO at 18:35 UTC. While the IMF was initially northwards, the IMF has become gradually more southwards and a geomagnetic disturbance began late on October 26. The source of the second shock was likely a CME observed after an M7 long duration event on October 24 in region 486. Solar wind speed ranged between 356 and 640 km/s, the planetary A index was 10.
Tuesday, October 28: The geomagnetic field was at unsettled to active levels. A CME was observed to pass the ACE spacecraft at around 01:30 UTC. Solar wind speed rose to near 800 km/s, but Bz stayed northward, thwarting a significant geomagnetic response. This shock was likely related to the arrival of the halo CME observed after an X1 flare in region 486 on October 26. Solar wind speed ranged between 459 and 808 km/s, the planetary A index was 20.
Wednesday, October 29: The geomagnetic field was at unsettled to extremely severe storm levels. The powerful CME from the X17/4b flare at 11:10 UTC on October 18, impacted the Earth's magnetic field at 06:13 UTC. The transit time for this CME was around 19 hours, making it one of the fastest on record (only a CME in 1859 is believed to have taken only 17 hours). The sudden impulse measured 140 nT on the Boulder magnetometer. Strong southward IMF Bz initiated severe (K9) storming at middle and high latitudes in the 06:00 - 09:00 period (maximum attainable level of 400 for the planetary A index during the 06-09h UTC interval). Mostly northward Bz occurred from 09:00 - 18:00 UTC; however, major to severe storming persisted. A sharp southward turn in the Bz occurred at around 18:00 UTC ending the SEC/NOAA period with K8-9 severe storming (IMF stayed very strongly southwards for the remainder of the day). Solar wind speed ranged between 572 and 1004 km/s (SOHO solar wind data during the 07-18h UTC interval was invalid due to the radiation storm and the solar storm. Solar wind speed probably exceeded 1200 km/sec during the early part of the disturbance). The planetary A index was 189. This geomagnetic storm is the strongest observed during solar cycle 23.
Thursday, October 30: The geomagnetic field was at predominantly minor to severe storm levels. The intense geomagnetic storm that began at 06:11 UTC on October 29 continued through the first half of this period. Severe (K8-9) levels were observed from 21:00 - 03:00 UTC. A short-lived "lull" (K5-6) in activity preceded the onset of another severe geomagnetic storm. The very fast CME from the X10 flare on October 29 impacted the magnetic field at around 16:00 UTC - a remarkably fast 19-hour transit from Sun to Earth. GOES-10,11, and 12 geosynchronous satellites have experienced magnetopause crossings and in fact have been outside the magnetopause for much of the time since the onset of this severe storm. Sustained southward IMF Bz in the -15 to -30 Nt range is assuring a severe response.
Friday, October 31: The geomagnetic field ranged from active to severe storm levels. The intense geomagnetic storm that began at around 16:00 UTC on October 30, continued well into this period. Severe storm levels persisted from 21:00 UTC through 09:00 UTC. Mostly active to major storm periods occurred through the latter half of the period. Solar radiation contamination on the ACE SWEPAM instrument finally ended at 00:52 UTC. Solar wind speed was at an exceptionally high 1200 km/s, but has been in a gradual decline, ending the period at over 800 km/s. The prolonged periods of southward IMF Bz that occurred early in the period have ended. Bz has been mostly northward since 02:00 UTC. The greater than 100 MeV proton event in progress since 11:45 UTC on October 30 ended at 01:45 UTC. This prolonged high energy proton event was actually two distinct events associated with the X17 and X10 flares on October 28 and 29 respectively.

September 2003
Monday, September 1: The geomagnetic field was quiet to active. Solar wind speed ranged between 361 and 582 km/s. The first part of the disturbance associated with a high speed coronal stream arrived at ACE just before 04:00 UTC. Initially the interplanetary magnetic field was moderately southwards, then mostly northwards between 07:00 and 16:00 UTC. After 16:00 UTC a fairly weak coronal hole stream dominated the solar wind. The planetary A index was 14.
Tuesday, September 2: The geomagnetic field has been quiet to active. Solar wind speed ranged between 467 and 612 km/s under the influence of a high speed coronal stream. The planetary A index was 12.
Wednesday, September 3: The geomagnetic field has been quiet to active. Solar wind speed ranged between 467 and 567 km/s under the influence of a high speed coronal stream. The planetary A index was 17.
Thursday, September 4: The geomagnetic field was unsettled to active. Solar wind speed ranged between 524 and 778 km/s under the influence of a high speed coronal stream. The planetary A index was 19.
Friday, September 5: The geomagnetic field was quiet to active. Solar wind speed ranged between 563 and 765 km/s under the influence of a high speed coronal stream. Wind speed decreased during the day and the disturbance associated with the coronal hole stream appeared to be ending late in the day. The planetary A index was 16.
Saturday, September 6: The geomagnetic field was quiet to unsettled with very isolated active periods. Solar wind speed ranged between 548 and 659 km/s under the weakening influence of a high speed coronal stream. The planetary A index was 12.
Sunday, September 7: The geomagnetic field was quiet to unsettled. Solar wind speed ranged between 387 and 549 km/s, the planetary A index was 10.
Monday, September 8: The geomagnetic field was quiet to unsettled. A high speed coronal stream began influencing the geomagnetic field after 17:00 UTC. Solar wind speed ranged between 363 and 487 km/s, the planetary A index was 9.
Tuesday, September 9: The geomagnetic field was quiet to active. Solar wind speed ranged between 444 and 717 km/s under the influence of a high speed coronal stream. The planetary A index was 19.
Wednesday, September 10: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 569 and 808 km/s under the influence of a high speed coronal stream. The planetary A index was 19.
Thursday, September 11: The geomagnetic field was at quiet to minor storm levels. Solar wind speed ranged between 561 and 743 km/s under the decreasing influence of a high speed coronal stream. The planetary A index was 15.
Friday, September 12: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 551 and 630 km/s, the planetary A index was 11.
Saturday, September 13: The geomagnetic field was at quiet to unsettled levels. The high speed stream of the past few days has ended. Solar wind speed ranged between 450 and 597 km/s, the planetary A index was 11.
Sunday, September 14: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 360 and 475 km/s, the planetary A index was 7.
Monday, September 15: The geomagnetic field was quiet to unsettled. A disturbance arrived at ACE at approximately 18:00 UTC. The most likely source of the disturbance is a CME observed early on September 12. Solar wind speed ranged between 347 and 383 km/s, the planetary A index was 6.
Tuesday, September 16: The geomagnetic field varied from unsettled to major storm conditions. The disturbance which began after 18:00 UTC on September 15 intensified as the interplanetary magnetic field at times was strongly southwards. A high speed coronal stream began to dominate the solar wind towards the end of the day. Solar wind speed ranged between 349 and 562 km/s, the planetary A index was 37.
Wednesday, September 17: The geomagnetic field was at active to severe storm levels. Solar wind speed ranged between 484 and 895 km/s under the influence of a strong high speed coronal stream. The planetary A index was 61.
Thursday, September 18: The geomagnetic field was at active to major storm levels. The effects of the high speed solar wind continue again today. Solar wind speed ranged between 753 and 965 km/s, the planetary A index was 40.
Friday, September 19: The geomagnetic field ranged from active to minor storm levels. This activity was due to the continued influence of a high speed solar wind stream associated with a favorably positioned coronal hole. Solar wind speed ranged between 595 and 874 km/s, the planetary A index was 32.
Saturday, September 20: The geomagnetic field was at unsettled to minor storm levels with an isolated major storm period at some locations between 03:00-06:00 UTC. Solar wind speed ranged between 580 and 865 km/s under the influence of a high speed coronal stream. The planetary A index was 25.
Sunday, September 21: The geomagnetic field ranged from quiet to active levels, with a period of minor storm at high latitudes from 12:00-15:00 UTC. A high speed solar wind from a coronal hole continues to drive the activity. Solar wind speed ranged between 475 and 671 km/s, the planetary A index was 21.
Monday, September 22: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 496 and 642 km/s under the influence of a high speed coronal stream. The planetary A index was 18.
Tuesday, September 23: The geomagnetic field was at unsettled to active levels. A coronal hole induced high speed stream continues to be geoeffective, causing minor disruptions in the Earth's magnetic field. Solar wind speed ranged between 467 and
549 km/s, the planetary A index was 17.
Wednesday, September 24: The geomagnetic field has been at active to minor storm levels. Solar wind speed ranged between 506 and 751 km/s under the influence of a high speed coronal stream. The planetary A index was 33.
Thursday, September 25: The geomagnetic field was at unsettled to minor storm levels. A favorably positioned high speed coronal hole stream is responsible for the elevated conditions. Solar wind speed ranged between 586 and 787 km/s, the planetary A index was 28.
Friday, September 26: The geomagnetic field was at unsettled to active levels. A coronal hole, which has induced a high-speed solar wind stream for the last few days, is in its final stages, but continues to impact the Earth's magnetic field. Solar wind speed ranged between 531 and 652 km/s, the planetary A index was 17.
Saturday, September 27: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 439 and 546 km/s, the planetary A index was 9.
Sunday, September 28: The geomagnetic field was at very quiet to slightly unsettled levels. Solar wind speed ranged between 346 and 441 km/s, the planetary A index was 6.
Monday, September 29: The geomagnetic field was at very quiet to slightly unsettled levels. Solar wind speed ranged between 346 and 441 km/s, the planetary A index was 6.
Tuesday, September 30: The geomagnetic field was at quiet to unsettled levels. The interplanetary magnetic field was weakly to moderately southwards most of the day, however, this didn't cause a noticeable increase in geomagnetic disturbance levels. Solar wind speed ranged between 275 and 364 km/s, the planetary A index was 7.

August 2003
Friday, August 1: The geomagnetic field has been at active to minor storm levels. A high speed solar wind stream flowing from a large coronal hole - combined with a series of periods where the interplanetary magnetic field has been oriented Southward - is responsible for the elevated activity.
Saturday, August 2: The geomagnetic field has been at unsettled to minor storm levels. The high speed stream associated with a significant coronal hole has been steady at approximately 720 km/s, making the geomagnetic field susceptible to variations in the interplanetary magnetic field.
Sunday, August 3: The geomagnetic field has been at unsettled to active levels. The coronal hole driven high speed stream has passed beyond geoeffective range.
Monday, August 4: The geomagnetic field was quiet to active. Solar wind speed continues to show a steady decline as the large southern coronal hole rotates out of a geoeffective position. Occasional periods of southward Bz account for the active levels.
Tuesday, August 5: The geomagnetic field was quiet to active. Solar wind speeds continued a steady decrease as the coronal hole moves out of geoeffective position.
Wednesday, August 6: The geomagnetic field was at quiet to severe storm levels. ACE satellite data indicated a consistent southward Bz at 02:00 UTC, with increasing solar wind speed thereafter, up to a maximum of 600 km/s. ACE data is consistent with the arrival of a co-rotating interaction region and associated high speed solar wind from an equatorial coronal hole moving into geoeffective position.
Thursday, August 7: The geomagnetic field has been at quiet to active levels. High solar wind speeds (up to 700 km/s), associated with a coronal hole in geoeffective position, are the likely cause of active conditions late in the period.
Friday, August 8: The geomagnetic field was at active to major storm levels. Periods of southward Bz near -8 nT produced major and minor storm periods early in the day. Solar wind speed increased from 600 km/s to near 800 km/s at 06:00 UTC and has remained elevated.
Saturday, August 9: The geomagnetic field was unsettled to active. The high speed solar wind stream is subsiding as the large equatorial coronal hole rotates out of a geoeffective position. Wind speed began the period near 750 km/s, but has gradually declined to near 650 km/s.
Sunday, August 10: The geomagnetic field was quiet to active. A declining high speed stream with very low density and weak northward IMF Bz continues to buffet the Earth's magnetic field. Solar wind speed declined from near 700 km/s to below 600 km/s by 21:00 UTC.
Monday, August 11: The geomagnetic field was at quiet to unsettled levels.
Tuesday, August 12: The geomagnetic field was at unsettled to minor storm levels. A recurrent high speed coronal hole stream that became effective early in the period is believed to be responsible for the elevated conditions.
Wednesday, August 13: The geomagnetic field ranged from quiet to minor storm levels. The elevated conditions are in response to a favorably positioned coronal hole.
Thursday, August 14: The geomagnetic field was at quiet to active levels. Sustained periods of southward Bz during night side regions allowed for active conditions.
Friday, August 15: The geomagnetic field was at quiet to active levels. Two periods of active conditions were observed. Solar wind speed remains elevated near 600 km/s and Bz was mostly northward.
Saturday, August 16: The geomagnetic field was at mostly unsettled to active conditions. Two periods of isolated active conditions were observed. Solar wind speed has decreased to below 500 km/s.
Sunday, August 17: The geomagnetic field was at quiet to minor storm levels.
A moderately strong solar wind shock passed the NASA/ACE spacecraft at 13:40 UTC with a 100 km/s increase in solar wind speed to 540 km/s and an increase in B-total to over 20 nT. The interplanetary magnetic field was mostly northwards for the remainder of the day. Solar wind speed ranged between 444 and 558 km/s, the planetary A index was 15.
Monday, August 18: The geomagnetic field was at minor to very severe storm levels. Around 01:00 UTC the Bz component of the interplanetary magnetic field turned southward to -15 nT with a peak near -25 nT. This shift in Bz resulted in sustained minor to severe storm levels until 15:00 UTC. Solar wind data are consistent with an interplanetary transient. Re-analysis of solar data for the past few days indicate activity in Region 431 (near center disk) late on August 14 as a possible source of this storm. Solar wind speed ranged between 444 and 636 km/s, the planetary A index was 86.
Tuesday, August 19: The geomagnetic field ranged from quiet to major storm levels.
The CME-induced disturbance that occurred yesterday appears to have ended. The field has been at unsettled to quiet levels since about 06:00 UTC. Solar wind speed ranged between 391 and 511 km/s, the planetary A index was 21.
Wednesday, August 20: The geomagnetic field was at quiet to active levels. Solar wind density increased slowly all day and peaked near 22:00 UTC. At this time a high speed coronal stream began dominating the solar wind. Solar wind speed ranged between 386 and 561 km/s, the planetary A index was 15.
Thursday, August 21: The geomagnetic field ranged from unsettled to severe storm levels. The most disturbed period was from 06:00 to 09:00 UTC. ACE solar wind data indicates the gradual onset of a coronal hole high-speed-stream over the past 24 hours. Solar wind speed ranged between 507 and 864 km/s, the planetary A index was 53.
Friday, August 22: The geomagnetic field ranged from unsettled to major storm levels. The high speed stream induced disturbance continues. Solar wind speed ranged between 749 and 944 km/s, the planetary A index was 43.
Saturday, August 23: The geomagnetic field ranged from unsettled to severe storm levels. Solar wind speed ranged between 673 and 887 km/s under the influence of a high speed coronal stream. The planetary A index was 44.
Sunday, August 24: The geomagnetic field was at unsettled to minor storm levels. One period of minor storm conditions was observed at 15:00 UTC. Solar wind speed ranged between 550 and 766 km/s under the influence of a decaying high speed stream. The planetary A index was 24.
Monday, August 25: The geomagnetic field ranged from unsettled to minor storm levels. Today's activity was initially at active levels in response to a high speed solar wind stream. Activity increased to minor storm levels from 06:00-09:00 UTC, but then backed off to mostly unsettled levels from 09:00 UTC through the end of the day. Solar wind speed ranged between 552 and 749 km/s, the planetary A index was 21.
Tuesday, August 26: The geomagnetic field was quiet to active. Solar wind speed ranged between 471 and 572 km/s, the planetary A index was 14.
Wednesday, August 27: The geomagnetic field was quiet to active. Solar wind speed ranged between 418 and 532 km/s, the planetary A index was 13.
Thursday, August 28: The geomagnetic field was unsettled to active. Solar wind speed ranged between 400 and 489 km/s, probably under the influence of a weak coronal stream. The planetary A index was 18.
Friday, August 29: The geomagnetic field was quiet to active. Solar wind speed ranged between 427 and 677 km/s under the influence of a high speed coronal stream. The planetary A index was 15.
Saturday, August 30: The geomagnetic field was quiet to minor storm. Solar wind speed ranged between 485 and 641 km/s, the planetary A index was 17.

July 2003
Tuesday, July 1: The geomagnetic field was at mostly quiet to unsettled levels, but there was an active period from 03:00-06:00 UTC. Solar wind speed ranged between 538 and 735 km/s under the weakening influence of a high speed coronal stream. The planetary A index was 13.
Wednesday, July 2: The geomagnetic field was at quiet to active levels. Solar wind conditions were nominal until about 18:00 UTC when an increase was observed in speed and temperature and a decrease was observed in density. This might indicate the onset of the anticipated high speed solar wind stream. Solar wind speed ranged between 452 and 617 km/s, the planetary A index was 15.
Thursday, July 3: The geomagnetic field ranged from quiet to active levels. Solar wind speeds increased up to around 600 km/s at 23:00 UTC on July 2, but dropped down to 500-550 km/s from 01:00-19:00 UTC. However, there appears to be another solar wind speed increase in progress at this time. Solar wind speed ranged between 478 and
690 km/s, the planetary A index was 17.
Friday, July 4: The geomagnetic field ranged from unsettled to minor storm levels. Two periods of minor storming occurred one at 06:00 UTC and another at 12:00 UTC. Solar wind speed ranged between 649 and 815 km/s under the influence of a high speed coronal stream. The planetary A index was 25.
Saturday, July 5: The geomagnetic field has been at unsettled to active levels. Solar wind speed ranged between 645 and 802 km/s under the influence of a high speed coronal stream. A sudden increase in solar wind speed near 10:10 UTC at ACE and atypical (for a high speed stream) development of other solar wind data - including the total field of the interplanetary magnetic field - indicate the presence of a CME embedded within the coronal hole flow. The most likely origin would be a CME associated with the M3 flare in region 397 on July 2. The planetary A index was 17.
Sunday, July 6: The geomagnetic field has been at quiet to unsettled levels. Solar wind speed ranged between 616 and 750 km/s. A solar wind disturbance was observed at
12:25 UTC at ACE. Initially there was only a minor increase in solar wind speed and a more distinct increase in the total field of the interplanetary magnetic field. The source of the disturbance is uncertain but does not appear to be a coronal hole flow. The planetary A index was 12.
Monday, July 7: The geomagnetic field was at quiet to active levels. Elevated solar wind speeds and periods of sustained southward Bz allowed for the observed intervals of isolated active conditions. Solar wind speed ranged between 457 and 738 km/s, generally decreasing all day. The planetary A index was 14.
Tuesday, July 8: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 439 and 545 km/s, the planetary A index was 5.
Wednesday, July 9: The geomagnetic field was quiet. Solar wind speed ranged between 379 and 485 km/s. A weak solar wind disturbance was observed at ACE after
18:00 UTC. Between 18:00 and 19:00 UTC solar wind speed increased from 380 to
450 km/s and solar wind density increased from 3 to 10 particles/cm3. While density has since stayed near 10 p/cm3, solar wind speed has decreased and is early on July 10 near 360 km/s. The planetary A index was 6.
Thursday, July 10: The geomagnetic field was at quiet to unsettled levels. The solar wind disturbance which began after 18:00 UTC on July 9 intensified after 16:00 UTC and the interplanetary magnetic field has since been moderately strongly southwards. The planetary A index was 8.
Friday, July 11: The geomagnetic field was at quiet to major storm levels. An extended period of southward Bz(-10 nT) led to the elevated conditions. A high speed coronal stream arrived at ACE at about 13:00 UTC. Until about 18:00 UTC the solar wind disturbance was a combination of the early effects from the coronal hole flow and the prior strong disturbance. The low speed disturbance which dominated the first half of the day intensified gradually and peaked at major storm levels between 08:00 and
09:00 UTC. Taking into account the low solar wind speed and events over the recent days, the most likely source of the disturbance may have been a large filament eruption (and CME) near the northwest limb, or an M-class flare with an associated CME in Region 400, both events occurred on July 6. Solar wind speed ranged between 347 and 706 km/s, the planetary A index was 46.
Tuesday, July 15: The geomagnetic field ranged from unsettled to minor storm levels. An initially active geomagnetic field reached minor storm levels from 00:00-06:00 UTC. Active to minor storm levels were also observed between 09:00-12:00 UTC. Conditions have been unsettled since 12:00 UTC. A solar wind disturbance which was observed beginning at ACE at 21:50 UTC on July 14 intensified early on June 15. Its most likely source is a filament eruption and an associated CME observed on July 11. A high speed coronal stream arrived at approximately 19:00 UTC on June 15 at ACE. Solar wind speed ranged between 548 and 612 km/s, the planetary A index was 27.
Wednesday, July 16: The geomagnetic field ranged from active to major storm levels. An initially active field attained storm levels after 03:00 UTC and continued at storm levels through 15:00 UTC. Conditions returned to active levels from 15:00 UTC through the end of the period. The increase in activity was associated with a slight increase in solar wind speed (600 to 650 km/s) and a noticeable increase in total magnetic field in the solar wind (ranging from 10 to 15 nT). The solar wind signatures are consistent for the most part with a high speed solar wind stream originating from a favorably positioned coronal hole. There may have been other sources contributing to the disturbance as well, particularly between 06:00 and 19:00 UTC when ACE solar wind data was somewhat atypical for a high speed stream. Solar wind speed ranged between 531 and 708 km/s, the planetary A index was 48.
Thursday, July 17: The geomagnetic field ranged from unsettled to minor storm levels. Today's solar wind continues to show the presence of a high speed coronal hole solar wind stream. Solar wind speed ranged between 567 and 771 km/s, the planetary A index was 22.
Monday, July 21: The geomagnetic field was at quiet to active levels. The field responded to the declining solar wind speed by returning to mostly quiet levels. Solar wind speed ranged between 400 and 668 km/s, the planetary A index was 12.
Tuesday, July 22: The geomagnetic field has been at quiet to unsettled levels. Solar wind speed ranged between 407 and 505 km/s, the planetary A index was 9.
Wednesday, July 23: The geomagnetic field has been at quiet to active levels. A fairly weak disturbance was observed at ACE beginning at 14:00 UTC when the interplanetary magnetic field suddenly swung moderately southwards and remained weakly to moderately southwards to the end of the day. The arrival of this disturbance was associated with an increase in solar wind speed from approximately 400 km/s to above 500 km/s. A possible source could be the partial halo CME observed on July 19. Solar wind speed ranged between 366 and 573 km/s, the planetary A index was 11.
Friday, July 25: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 311 and 388 km/s, the planetary A index is estimated at 11.
Saturday, July 26: The geomagnetic field was at quiet to minor storm levels. Solar wind speeds began to increase today after 18:30 UTC from around 400 km/s to above
560 km/s, with a sustained southward Bz. The probable source of this high speed stream is a E-W oriented coronal hole which is now rotating into a geoeffective location.
Sunday, July 27: The geomagnetic field was at quiet to minor storm levels. A recurrent high speed coronal hole stream and a sustained southward Bz are believed responsible for the elevated activity. The solar wind speed exceeded 800 km/s at approximately
06:00 UTC. NASA/ACE data also indicates a possible transient passage very early in the period. Solar wind speed ranged between 591 and 851 km/s, the planetary A index was 24.
Monday, July 28: The geomagnetic field was at quiet to minor storm levels. A recurrent high speed coronal hole stream is believed to be responsible for the elevated conditions. Solar wind speed ranged between 521 and 839 km/s, the planetary A index was 17.
Tuesday, July 29: The geomagnetic field was at predominantly active to minor storm levels. Solar wind speed ranged between 695 and 917 km/s, the planetary A index
was 36. A period of major storm conditions were observed at the Boulder magnetometer between 03:00 and 06:00 UTC. The elevated activity is in response to a recurrent coronal hole high speed solar wind stream. This coronal hole has been with us at least since October 2002 in various shapes. During this solar rotation it is at its most impressive with an exceptionally high maximum solar wind speed.
Wednesday, July 30: The geomagnetic field was at unsettled to minor storm levels. A recurrent high speed coronal hole stream remains geoeffective. Solar wind speed ranged between 701 and 980 km/s, the planetary A index was 29.
Thursday, July 31: The geomagnetic field was at predominantly active to minor storm levels. The recurrent high speed coronal hole stream continues to be geoeffective. Solar wind speed ranged between 752 and 962 km/s, the planetary A index was 32.

June 2003
Sunday, June 1: The geomagnetic field was at quiet to active levels. A high speed coronal stream arrived early in the day and strengthened gradually. Solar wind speed ranged between 560 and 708 km/s, the planetary A index was 19.
Monday, June 2: The geomagnetic field ranged from unsettled to major storm levels. The most disturbed periods were from 06:00 to 12:00 UTC. Solar wind speed ranged between 586 and 767 km/s under the influence of a high speed coronal stream. The planetary A index was 39.
Tuesday, June 3: The geomagnetic field was mostly unsettled to active. Isolated minor storm periods occurred from 09:00-12:00 UTC and from 21:00-24:00 UTC. Solar wind data continue to indicate the presence of a high speed wind stream, which is due to a favorably positioned coronal hole. Solar wind speed ranged between 690 and 881 km/s, the planetary A index was 26.
Wednesday, June 4: The geomagnetic field was at unsettled to active levels. Solar wind speed ranged between 668 and 854 km/s under the influence of a high speed coronal stream. The planetary A index was 21.
Thursday, June 5: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 461 and 750 km/s under the influence of a high speed coronal stream. The planetary A index was 13.
Friday, June 6: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 482 and 703 km/s under the influence of a high speed coronal stream. The planetary A index was 13.
Saturday, June 7: The geomagnetic field was at active to minor storm levels. Solar wind speed ranged between 573 and 758 km/s under the influence of a high speed coronal stream. The planetary A index was 24.
Sunday, June 8: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 609 and 767 km/s under the influence of a high speed coronal stream. The planetary A index was 27.
Monday, June 9: The geomagnetic field was at unsettled to major storm levels. Solar wind speed ranged between 577 and 754 km/s, mainly under the influence of a high speed coronal stream. A CME embedded within the coronal hole flow may have arrived after 11:00 UTC and caused an increase in geomagnetic activity late in the day. The planetary A index was 28.
Tuesday, June 10: The geomagnetic field was at unsettled to major storm levels. Solar wind speed ranged between 600 and 764 km/s under the influence of a high speed coronal stream. The planetary A index was 27.
Wednesday, June 11: The geomagnetic field was at unsettled to active levels. Solar wind speed ranged between 561 and 751 km/s under the influence of a high speed coronal stream until about 16:00 UTC when the stream appeared to be ending. The planetary A index was 15.
Thursday, June 12: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 456 and 567 km/s, the planetary A index was 11.
Friday, June 13: The geomagnetic field has been at quiet to minor storm levels. Solar wind speed began increasing after 17:00 UTC as a high coronal speed stream began to dominate the solar wind. Solar wind speed ranged between 370 and 476 km/s, the planetary A index was 11.
Saturday, June 14: The geomagnetic field was at active to major storm levels. The onset of the expected coronal hole was marked by a co-rotating interacting region with solar wind speed increasing to near 600 km/s and a 12 hour period of minor storm levels. Late in the period indications of a possible shock passage at the NASA/ACE spacecraft coincided with a major storm period. The interplanetary magnetic field was mostly northwards for the remainder of the day. Solar wind speed ranged between 447 and
621 km/s, the planetary A index was 32.
Sunday, June 15: The geomagnetic field was at unsettled to minor storm levels. The high speed coronal stream ended early in the evening. At about 19:00 UTC a new and short lived disturbance arrived as solar wind speed increased and ACE EPAM data indicated the arrival of a CME. This disturbance has not been particularly geoeffective so far with the interplanetary magnetic field nearly constantly northwards. Solar wind speed ranged between 473 and 583 km/s, the planetary A index was 20.
Monday, June 16: The geomagnetic field was at quiet to major storm levels. While the disturbance which arrived at approximately 19:00 UTC on June 15 was not very impressive during the first hours after its arrival, the geomagnetic effects increased early on June 16 with minor storming observed. Activity decreased after noon but then another disturbance arrived. Both solar wind speed and the total field of the interplanetary magnetic field increased suddenly near 16:45 UTC. By 19:00 UTC solar wind speed had increased from 450 to 550 km/s and later on leveled out between 520 and 540 km/s. The new disturbance caused an increase in geomagnetic activity levels with major storming observed late in the day. Solar wind speed ranged between 430 and 578 km/s, the planetary A index was 32.
Tuesday, June 17: The geomagnetic field was at active to major storm levels. A six-hour period of southward Bz, from 06:00 - 09:00 UTC combined with elevated solar wind speed near 510 km/s produced minor and major storm levels. Solar wind speed ranged between 453 and 554 km/s, the planetary A index was 50.
Wednesday, June 18: The geomagnetic field was at predominantly minor to major storm levels with an isolated period of severe storm conditions seen at high latitudes between 06:00 and 09:00 UTC. A moderately strong solar wind shock was observed at SOHO at 04:44 UTC. The interplanetary magnetic field was mostly moderately to strongly southwards for several hours after the shock and this caused major to severe geomagnetic storming lasting until noon. The source of this shock is likely the full halo CME observed on June 15/16. A high speed coronal stream dominated the solar wind after 15:00 UTC. Solar wind speed ranged between 417 and 665 km/sec, the planetary
A index was 54.
Thursday, June 19: The geomagnetic field was at quiet to minor storm levels. Minor storm conditions were observed at both middle and high latitudes between 00:00 and 03:00 UTC due to the influence of a recurrent high speed coronal hole stream. Solar wind speed ranged between 489 and 644 km/s, the planetary A index was 18.
Friday, June 20: The geomagnetic field was at quiet to unsettled levels. A weak solar wind shock was observed at SOHO at 07:59 UTC. This was likely the arrival of the full halo CME observed on June 17. Just after the arrival of the CME the interplanetary magnetic field swung southwards for a short time but then returned northwards and stayed mostly northwards for the remainder of the day. Solar wind speed ranged between 475 and 604 km/s, the planetary A index was 12.
Saturday, June 21: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 472 and 564 km/s under the influence of a high speed coronal stream. Sustained periods of southward Bz along with elevated solar wind speeds led to the occasional storming conditions. The planetary A index was 23.
Sunday, June 22: The geomagnetic field was unsettled to active on June 22. Solar wind speed ranged between 453 and 581 km/s under the influence of a high speed coronal stream. The planetary A index was 16.
Monday, June 23: The geomagnetic field was at unsettled to active levels with an isolated minor storm period between 03:00-06:00 UTC. Solar wind speed ranged between 453 and 583 km/s under the influence of a high speed coronal stream. The planetary A index was 20.
Tuesday, June 24: The geomagnetic field ranged from quiet to minor storm levels. Active to minor storm levels were predominant during local nighttime hours. Solar wind speed ranged between 467 and 580 km/s under the influence of a high speed stream. The planetary A index was 31.
Wednesday, June 25: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 510 and 576 km/s under the influence of a high speed coronal stream. The planetary A index was 19.
Thursday, June 26: The geomagnetic field was at unsettled to active levels. Solar wind speed ranged between 477 and 686 km/s. A high speed coronal stream arrived at ACE just before noon with solar wind speed increasing to near 700 km/s. The planetary A index was 19.
Friday, June 27: The geomagnetic field was at unsettled to major storm levels. Solar wind speed ranged between 611 and 768 km/s under the influence of a high speed coronal stream. The planetary A index was 28.
Saturday, June 28: The geomagnetic field was at unsettled to major storm levels. The magnetosphere remained under the influence of a high speed stream emanating from the large coronal hole in the western solar hemisphere. Solar wind speed ranged between 609 and 763 km/s, the planetary A index was 32.
Sunday, June 29: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 655 and 779 km/s under the influence of a high speed coronal stream. The planetary A index was 26.
Monday, June 30: The geomagnetic field ranged from unsettled to minor storm levels. The disturbance is due to a high speed solar wind stream associated with a well-positioned solar coronal hole. Solar wind speed ranged between 673 and 791 km/s, the planetary A index was 20.

May 2003
Thursday, May 1: The geomagnetic field was at unsettled to major storm levels. Periods of southward Bz combined with the elevated wind speed has produce minor storming and one period of major storm levels. Solar wind speed ranged between 575 and
715 km/s under the influence of a high speed coronal stream. The stream was weakening slowly towards the end of the day. The planetary A index was 40.
Friday, May 2: The geomagnetic field was at mostly quiet to unsettled levels with a single minor storm interval 03:00-06:00 UTC. Solar wind speed ranged between 480 and 611 km/s under the decreasing influence of a high speed coronal stream. The planetary A index was 17.
Saturday, May 3: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 445 and 552 km/s, the planetary A index was 10.
Sunday, May 4: The geomagnetic field has been at quiet to unsettled levels. The apparent onset of a high speed coronal hole stream was observed at ACE near
14:30 UTC. The interplanetary magnetic field has since been mostly northwards or weakly southwards. The major part of the disturbance has not yet arrived. Solar wind speed ranged between 350 and 449 km/s, the planetary A index was 7.
Monday, May 5: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 413 and 679 km/s, increasingly under the influence of a high speed coronal stream. The planetary A index was 12.
Tuesday, May 6: The geomagnetic field was at quiet to minor storm levels. Solar wind speed ranged between 566 and 780 km/s under the influence of a high speed coronal stream. The planetary A index was 23.
Wednesday, May 7: The geomagnetic field was at unsettled to major storm levels. Solar wind speed ranged between 600 and 769 km/s under the influence of a high speed coronal stream. The planetary A index was 36.
Thursday, May 8: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 639 and 786 km/s under the influence of a high speed coronal stream. The planetary A index was 30.
Friday, May 9: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 665 and 986 km/s. Early in the day a high speed coronal stream dominated the solar wind, then, at 04:49 UTC at SOHO, an unusual disturbance arrived. Solar wind speed in the 750 to near 1000 km/s range was recorded until about 11:00 UTC. The source of this disturbance is at this time not obvious. The geomagnetic disturbance intensified strongly early on May 10 and reached major storm level. The planetary A index was 29.
Saturday, May 10: The geomagnetic field was at quiet to major storm levels. Solar wind speed ranged between 505 and 769 km/s. The disturbance which began on May 9 decreased in intensity after 11:00 UTC and was gradually replaced by a high speed coronal stream. While the source of the disturbance is not obvious, close examination of SXI images on May 7 revealed a filament eruption beginning at approximately
14:00 UTC. The planetary A index was 43.
Sunday, May 11: The geomagnetic field was at unsettled to major storm levels. Solar wind speed ranged between 552 and 712 km/s under the influence of a high speed coronal stream. The planetary A index was 31.
Monday, May 12: The geomagnetic field was at unsettled to active levels. Solar wind speed ranged between 584 and 760 km/s under the influence of a high speed coronal stream. The planetary A index was 18.
Tuesday, May 13: The geomagnetic field was mostly active on May 13 with a single unsettled interval 03:00-06:00 UTC and a minor storm interval 09:00-12:00 UTC. Solar wind speed ranged between 607 and 787 km/s under the influence of a high speed coronal stream. The planetary A index was 27.
Wednesday, May 14: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 630 and 776 km/s under the influence of a high speed coronal stream. The planetary A index was 27.
Thursday, May 15: The geomagnetic field was at unsettled to active levels. Solar wind speed ranged between 586 and 751 km/s under the influence of a slowly diminishing high speed coronal stream. The planetary A index was 23.
Friday, May 16: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 504 and 656 km/s, the high speed coronal stream ended early in the day. The planetary A index was 9.
Saturday, May 17: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 449 and 563 km/s, the planetary A index was 9.
Sunday, May 18: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 383 and 468 km/s. A slow increase in solar wind speed was observed after 15:00 UTC as a fairly weak high speed coronal stream began to dominate the solar wind. The planetary A index was 10.
Monday, May 19: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 382 and 448 km/s under the influence of a fairly weak high speed coronal stream. The planetary A index was 12.
Tuesday, May 20: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 379 and 454 km/s under the influence of a weak high speed coronal stream. The planetary A index was 12.
Wednesday, May 21: The geomagnetic field was at quiet to minor storm levels. Solar wind speed ranged between 353 and 563 km/s. A high speed coronal stream arrived at approximately 11:00 UTC at ACE and dominated the solar wind for the remainder of the day. The planetary A index was 20.
Thursday, May 22: The geomagnetic field was at quiet to minor storm levels. Solar wind speed ranged between 451 and 528 km/s under the influence of a high speed coronal stream. The planetary A index was 25.
Friday, May 23: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 443 and 509 km/s under the influence of a high speed coronal stream. The planetary A index was 21.
Saturday, May 24: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 431 and 581 km/s under the influence of a high speed coronal stream. The planetary A index was 23.
Sunday, May 25: The geomagnetic field was at quiet to minor storm levels. Solar wind speed ranged between 473 and 631 km/s, peaking early in the day under the influence of a high speed coronal stream. The coronal hole flow appeared to be ending late on
May 25. The planetary A index was 22.
Monday, May 26: The geomagnetic field was at unsettled to active levels. Solar wind speed ranged between 440 and 539 km/s. A high speed coronal stream was observed beginning at ACE at approximately 23:30 UTC. The planetary A index was 18.
Tuesday, May 27: The geomagnetic field was at unsettled to minor storm levels. Solar wind speed ranged between 452 and 646 km/s under the influence of a high speed coronal stream. The planetary A index was 26.
Wednesday, May 28: The geomagnetic field was at active to major storm levels. Solar wind speed ranged between 585 and 716 km/s under the influence of a high speed coronal stream. The stream weakened during the latter half of the day. The planetary
A index was 36.
Thursday, May 29: The geomagnetic field was at unsettled to very severe storm levels on May 29. A recurrent coronal hole was responsible for the initial elevated conditions.
A solar wind shock was observed at 11:52 UTC at SOHO with a sudden increase in solar wind speed from 567 to 689 km/s. The source of this disturbance was likely a full halo CME (transit time: 53 hours) observed after a long duration M1.6 event on May 27. Another and very strong solar wind shock was observed at 18:34 UTC when solar wind speed increased abruptly from 691 to 763 km/s. This shock was caused by the arrival of the 2 halo CME's (transit time: 43-44 hours) observed after the X1 flare late on May 27 and X3 flare early on May 28. The interplanetary magnetic field was soon after the arrival of this disturbance extremely strongly southwards and caused very severe geomagnetic storm conditions with the planetary A index for the 21-24h UTC interval reaching 231. Solar wind speed ranged between 565 and 814 km/s, the planetary A index was 89.
Friday, May 30: The geomagnetic field ranged from unsettled to very severe storm levels. The field was mostly unsettled to active since about 06:00 UTC with a single minor storm period from 15:00-18:00 UTC. The CME associated with the X1 flare early on 29 May was apparently observed to encounter the ACE spacecraft at about
16:00 UTC with an abrupt increase in solar wind speed from 610 to 770 km/s. The shock in solar wind parameters was not strong and an SI was not clearly observed by ground magnetometers. The interplanetary magnetic field, having been mostly northwards since 02:00 UTC, swung strongly southwards at first, then became northwards again and weakened towards the end of the day. Solar wind speed ranged between 558 and
782 km/s, the planetary A index was 49.
Saturday, May 31: The geomagnetic field ranged from quiet to major storm levels. The most disturbed period occurred from 03:00-06:00 UTC and has since been quiet to unsettled at most locations. Solar wind speed ranged between 555 and 775 km/s, the planetary A index was 17.

April 2003
Tuesday, April 1: The geomagnetic field was at quiet to minor storm levels, with occasional major storming at high latitudes. The high speed stream that began early on March 30 continued during the period. Solar wind speed ranged between 452 and
561 km/s, the planetary A index was 12.
Wednesday, April 2: The geomagnetic field was at quiet to active levels. The high speed stream that began on March 30 has gained slightly in strength to nearly 580 km/s. Intermittently southward Bz has generated disturbed periods. Solar wind speed ranged between 446 and 555 km/s, the planetary A index was 20.
Thursday, April 3: The geomagnetic field was at quiet to active levels. The high speed stream which began on March 30 is subsiding, but continued instability in the interplanetary magnetic field is maintaining our unsettled activity levels. Solar wind speed ranged between 435 and 482 km/s, the planetary A index was 14.
Friday, April 4: The geomagnetic field has been at quiet to active levels with periods of minor storming due to the continued influence of a high-speed solar wind stream. Solar wind speed ranged between 459 and 509 km/s, the planetary A index was 26.
Saturday, April 5: The geomagnetic field was at unsettled to active levels with one period of minor storm conditions. Solar wind speed ranged between 443 and 541 km/s under the influence of a high speed coronal stream. The planetary A index was 23.
Sunday, April 6: The geomagnetic field was at quiet to unsettled conditions. High speed stream effects have diminished. Solar wind speed ranged between 369 and 550 km/s, slowly decreasing all day. The planetary A index was 9.
Monday, April 7: The geomagnetic field was at quiet to unsettled levels. Solar wind speed ranged between 349 and 378 km/s. The planetary A index was 6.
Tuesday, April 8: The geomagnetic field was at quiet to minor storm levels. A solar wind shock was observed at SOHO at 00:03 UTC. The source of this shock is likely a CME observed after an M2 event on April 4. The interplanetary magnetic field was moderately southwards after the shock and this caused an increase in geomagnetic disturbance levels to minor storm. Solar wind speed ranged between 353 and 481 km/s, the planetary A index was 20.
Wednesday, April 9: The geomagnetic field was at quiet to minor storm levels. A high speed coronal stream began to dominate the solar wind after 17:00 UTC, prior to that the disturbance which began on April 8 appears to have mixed with another high speed coronal stream. Solar wind speed ranged between 393 and 510 km/s, the planetary
A index was 25.
Thursday, April 10: The geomagnetic field was at mostly active to minor storm levels. Solar wind speed ranged between 496 and 722 km/s, gradually increasing all day under the influence of a high speed coronal stream. The planetary A index was 26.
Friday, April 11: The geomagnetic field was at quiet to active levels. Solar wind speed ranged between 536 and 748 km/s under the influence of a high speed coronal stream. Wind speed generally decreased throughout the day. The planetary A index was 14.
Saturday, April 12: The geomagnetic field was quiet to unsettled. Solar wind speed ranged between 509 and 690 km/s under the influence of a fairly benign high speed coronal stream. The planetary A index was 7.
Sunday, April 13: The geomagnetic field was quiet to unsettled. Solar wind speed ranged between 444 and 561 km/s, the planetary A index was 10.
Monday, April 14: The geomagnetic field ranged from quiet to active levels, with a period of minor storm conditions at high latitudes from 12:00-15:00 UTC. The enhanced activity was associated with an extended interval of moderately strong (-5 to -10 nT) southward orientation of the interplanetary magnetic field Bz component between 11:00-15:00 UTC. Solar wind speed and temperature showed a gradual increasing t