NOAA SEC Report of Solar-Geophysical Activity 22 Apr 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Apr 22 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 112 Issued at 2200Z on 22 Apr 2001
IA.  Analysis of Solar Active Regions and Activity from  21/2100Z
to 22/2100Z:  Solar activity was moderate due to an M3/1N flare at
22/2044 UTC in Region 9433 (N17E26). The flare was associated with a
tenflare of 270 sfu and a weak type II sweep. This Region remains a
large F-type sunspot group with mixed spot polarities. Spot growth
has resulted in the formation of at least two small delta
configurations in the central and leading sunspots.
IB.  Solar Activity Forecast:  Solar activity is expected to be
moderate. Additional M-class flares are likely in Region 9433. The
possibility of a major flare is increasing as sunspot growth and
magnetic complexity develops.
IIA.  Geophysical Activity Summary 21/2100Z to 22/2100Z:
The geomagnetic field ranged from quiet to minor storm levels. This
activity is most likely related to the passage of one of the CMEs
observed over the northwest limb earlier this week.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at active to minor storm levels becoming unsettled to
active within the next 24 hours. There is a chance of an energetic
proton event if a major flare occurs in Region 9433.
III.  Event Probabilities 23 Apr-25 Apr
Class M    75/75/75
Class X    10/10/10
Proton     05/05/05
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           22 Apr 193
Predicted   23 Apr-25 Apr  205/210/210
90 Day Mean        22 Apr 166
V.  Geomagnetic A Indices
Observed Afr/Ap 21 Apr  007/007
Estimated Afr/Ap 22 Apr  030/030
Predicted Afr/Ap 23 Apr-25 Apr  015/010-010/010-010/010
VI.  Geomagnetic Activity Probabilities 23 Apr-25 Apr
A.  Middle Latitudes
Active                15/10/10
Minor storm           10/05/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                25/15/10
Minor storm           20/10/05
Major-severe storm    10/05/01