NOAA SEC Report of Solar-Geophysical Activity 29 Mar 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Mar 29 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 088 Issued at 2200Z on 29 Mar 2001
IA.  Analysis of Solar Active Regions and Activity from  28/2100Z
to 29/2100Z:  Solar activity was high.  Region 9393 (N17W18) produced
an X1/1N event at 29/1015Z.  This event had an associated Type IV
radio sweep, a tenflare of 4700 sfu, and a full halo CME was
reported from LASCO/SOHO imagery.  This earth-directed CME occurred
at approximately 29/1030Z.  Region 9393 also produced numerous minor
M-class events during the period.  Region 9393 has shown slight
growth in area since yesterday and is currently over 2400 millionths
in white light.  No new regions were numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be high.
Region 9393 still has the best potential to produce a major flare.
IIA.  Geophysical Activity Summary 28/2100Z to 29/2100Z:
The geomagnetic field was quiet to minor storm.  The greater than 10
MeV protons crossed the 10 pfu event threshold at 29/1635Z and has
not yet peaked (highest flux observed so far was 18 pfu at
29/2050Z).
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to increase during the first day of the period to active to
major storms levels due to a CME passage.  The passage of a faster
CME, from the X1 event today, may occur later on the first day. 
With the passage of the second CME, conditions are expected to be at
active to major storm levels with isolated severe conditions
possible.  During the last half of the period, conditions are
expected to decrease to unsettled to active conditions.  CME passage
could increase the strength and duration of the 10 MeV proton event
currently in progress.  Another proton event is possible, and likely
stronger, if Region 9393 produces another major flare as it transits
the solar western hemisphere.
III.  Event Probabilities 30 Mar-01 Apr
Class M    80/80/80
Class X    30/30/30
Proton     99/30/30
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           29 Mar 262
Predicted   30 Mar-01 Apr  260/255/250
90 Day Mean        29 Mar 163
V.  Geomagnetic A Indices
Observed Afr/Ap 28 Mar  019/031
Estimated Afr/Ap 29 Mar  020/025
Predicted Afr/Ap 30 Mar-01 Apr  045/050-045/050-025/030
VI.  Geomagnetic Activity Probabilities 30 Mar-01 Apr
A.  Middle Latitudes
Active                30/20/40
Minor storm           40/50/30
Major-severe storm    20/25/15
B.  High Latitudes
Active                20/10/30
Minor storm           40/40/40
Major-severe storm    30/40/20