NOAA SEC Report of Solar-Geophysical Activity 5 Apr 2001
:Product: Report of Solar-Geophysical Activity :Issued: 2001 Apr 05 2200 UT # Prepared jointly by the U.S. Dept. of Commerce, NOAA, #Space Environment Center and the U.S. Air Force. # Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 095 Issued at 2200Z on 05 Apr 2001 IA. Analysis of Solar Active Regions and Activity from 04/2100Z to 05/2100Z: Solar activity was high. Two major flares were observed during the past 24 hours. The first was a long-duration M8 that peaked at 0922Z, originating from Region 9393 behind the west limb. This flare was associated with a CME which gives every indication of moving in a westward direction, perpendicular to the Earth-Sun line. The second was an M5/2n at 1725Z from Region 9415 (S21E47). This event had an extended maximum and a slow decay profile. An associated CME was just entering the C2 field of view at forecast issue time and did not appear to have any earthward component. Region 9415 appears to have formed a delta configuration in the leader portion of the group. Region 9417 (S08E27) grew rapidly during the last 24 hours and produced an M1/Sn flare at 0834Z. Today's 10.7 cm background flux of 210 SFU had to be estimated due to greatly enhanced radio noise levels occurring with today's long-duration flare activity. IB. Solar Activity Forecast: Solar activity is expected to be mostly moderate during the next three days. There is a fair chance, however, for additional major flares from Region 9415. IIA. Geophysical Activity Summary 04/2100Z to 05/2100Z: The geomagnetic field was predominantly quiet to active during the past 24 hours. The first nine hours of the period were quiet, but activity increased to mostly active from 0600-2100Z. There was a minor storm period at high latitudes from 0900-1200Z. The greater than 10 MeV proton event continues in progress with a continued slow decline in flux levels. The flux at 05/2100Z was 25 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly unsettled tomorrow, with a chance for some isolated active periods. Predominantly unsettled levels should prevail for the second and third days. III. Event Probabilities 06 Apr-08 Apr Class M 75/75/75 Class X 20/20/20 Proton 99/20/20 PCAF in progress IV. Penticton 10.7 cm Flux Observed 05 Apr 210 Predicted 06 Apr-08 Apr 210/210/205 90 Day Mean 05 Apr 167 V. Geomagnetic A Indices Observed Afr/Ap 04 Apr 012/015 Estimated Afr/Ap 05 Apr 015/015 Predicted Afr/Ap 06 Apr-08 Apr 015/015-012/008-012/008 VI. Geomagnetic Activity Probabilities 06 Apr-08 Apr A. Middle Latitudes Active 30/25/20 Minor storm 15/10/10 Major-severe storm 10/05/05 B. High Latitudes Active 30/25/20 Minor storm 20/15/10 Major-severe storm 15/10/10
