NOAA SEC Report of Solar-Geophysical Activity 9 Apr 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Apr 09 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 099 Issued at 2200Z on 09 Apr 2001
IA.  Analysis of Solar Active Regions and Activity from  08/2100Z
to 09/2100Z:  Solar activity increased to high levels. Region 9415
(S22W07) produced an M7/2B flare at 09/1534 UTC associated with a
1600 SFU Tenflare, Type II and IV radio sweeps, and a full-halo CME.
Region 9415 remained a large, magnetically complex group with a
strong, persistent magnetic delta configuration within the large
leader spot. The remaining regions were simply-structured and showed
no significant changes. New Region 9425 (S25W26) was numbered.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
moderate to high levels. Region 9415 could produce another major
flare during the period.
IIA.  Geophysical Activity Summary 08/2100Z to 09/2100Z:
Geomagnetic field activity ranged from quiet to minor storm levels as
CME effects gradually subsided. The greater than 10 MeV proton flux
began to rise after today's major flare and was gradually increasing
as the period ended. A greater than 100 MeV proton flux enhancement
also followed the flare, but did not reach event levels.
IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is
expected to decrease to quiet to unsettled levels on 10 April. The
CME associated with today's flare is expected to reach Earth during
the early hours of 11 April. Active to major storm levels will be
possible during 11 - 12 April as the CME passes Earth. The greater
than 10 MeV proton flux may increase to event levels early on 10
April.
III.  Event Probabilities 10 Apr-12 Apr
Class M    80/80/80
Class X    25/25/25
Proton     70/25/25
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           09 Apr 165
Predicted   10 Apr-12 Apr  165/160/160
90 Day Mean        09 Apr 167
V.  Geomagnetic A Indices
Observed Afr/Ap 08 Apr  033/041
Estimated Afr/Ap 09 Apr  018/025
Predicted Afr/Ap 10 Apr-12 Apr  012/015-030/035-025/025
VI.  Geomagnetic Activity Probabilities 10 Apr-12 Apr
A.  Middle Latitudes
Active                25/30/40
Minor storm           10/30/20
Major-severe storm    05/25/05
B.  High Latitudes
Active                30/20/40
Minor storm           15/35/15
Major-severe storm    05/20/10