Viewing archive of Sunday, 18 July 2004

Solar activity report

Report of Solar-Geophysical Activity 2004 Jul 18 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 200 Issued at 2200Z on 18 Jul 2004

IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z

Solar activity remained at high levels today. Region 649 (S10E00) produced five M-class events, all of which occurred in a constricted area around the delta structure in the trailing portion of the spot group. The M-class flares chronologically occurred with an M2/1f at 17/2131Z, an M1 x-ray at 17/2308Z, an M2/1f at 18/0035Z, an M1/Sf at 18/0257Z, and an M1/1f at 18/1713Z. Weak radio bursts accompanied many of today's events while LASCO imagery depicted only faint CME signatures in association with the flare activity observed during the period. Magnetically, Region 649 remains a beta-gamma-delta spot group. Region 652 (N05E58) has fully rotated into view today and is currently measured in white light at over 1300 millionths of spot area coverage. Several C-class flares were observed during the period and a strong delta structure is evident in the intermediate cluster of spots. No new regions were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be at moderate to high levels. Region 649 and 652 are both capable of producing major flare level activity.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was at quiet to unsettled levels.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at predominantly unsettled levels throughout the period. Isolated active to minor storm conditions are possible on 19 and 20 July mostly at higher latitudes due to the potential for transient passages from the major flare activity seen from Region 649 during the past several days.
III. Event Probabilities 19 Jul to 21 Jul
Class M80%80%80%
Class X40%40%40%
IV. Penticton 10.7 cm Flux
  Observed       18 Jul 155
  Predicted   19 Jul-21 Jul  150/150/145
  90 Day Mean        18 Jul 098
V. Geomagnetic A Indices
  Observed Afr/Ap 17 Jul  013/024
  Estimated     Afr/Ap 18 Jul  008/010
  Predicted    Afr/Ap 19 Jul-21 Jul  010/015-010/015-008/012
VI. Geomagnetic Activity Probabilities 19 Jul to 21 Jul
A. Middle Latitudes
Minor storm10%10%05%
Major-severe storm05%05%01%
B. High Latitudes
Minor storm15%15%10%
Major-severe storm10%10%05%

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