NOAA SEC Report of Solar-Geophysical Activity 16 Apr 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Apr 16 2210 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 106 Issued at 2200Z on 16 Apr 2001
IA.  Analysis of Solar Active Regions and Activity from  15/2100Z
to 16/2100Z:  Solar activity was moderate.  An optically uncorrelated
M1 event occurred at 16/0622 UTC.  New Region 9430 (S16W33) was
numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
to moderate.
IIA.  Geophysical Activity Summary 15/2100Z to 16/2100Z:
The geomagnetic field was quiet to unsettled.  The greater than 10
MeV and greater than 100 MeV proton events that started yesterday
are still in progress.  Peak flux for the greater than 10 MeV
protons was 951 pfu at 15/1920 UTC and the peak flux for the greater
than 100 MeV was 146 pfu at 15/1525 UTC.  The greater than 2 MeV
electrons at geosynchronous orbit were at high levels and remained
above threshold through the period.  The polar cap absorption (PCA)
event that started yesterday is still in progress.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be unsettled to active for April 17.  Active to minor
storm conditions are expected for April 18 as a result of the X14/2b
flare on April 15, and possible effects from a well positioned
coronal hole.  Unsettled to active conditions are expected to return
on April 19.  The greater than 10 MeV proton event is expected to
continue for most of the period, and the greater than 100 MeV proton
event is expected to go below threshold sometime on April 17.
III.  Event Probabilities 17 Apr-19 Apr
Class M    70/60/50
Class X    25/10/10
Proton     99/50/10
PCAF       in progress
IV.  Penticton 10.7 cm Flux
Observed           16 Apr 123
Predicted   17 Apr-19 Apr  130/140/150
90 Day Mean        16 Apr 165
V.  Geomagnetic A Indices
Observed Afr/Ap 15 Apr  009/013
Estimated Afr/Ap 16 Apr  010/012
Predicted Afr/Ap 17 Apr-19 Apr  015/020-020/035-015/030
VI.  Geomagnetic Activity Probabilities 17 Apr-19 Apr
A.  Middle Latitudes
Active                25/50/25
Minor storm           05/10/05
Major-severe storm    01/05/01
B.  High Latitudes
Active                35/60/50
Minor storm           10/15/15
Major-severe storm    05/10/10