:Product: 20020419RSGA.txt
:Issued: 2002 Apr 19 2200 UTC
# 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 109 Issued at 2200Z on 19 Apr 2002
IA.  Analysis of Solar Active Regions and Activity from  18/2100Z
to 19/2100Z:  Solar activity was low. Region 9906 (S14W66) produced
several C-class subflares during the past day. The largest was a
C3/Sf at 19/1822 UTC. This region continues to decay slowly but
retains appreciable size and magnetic complexity. New Regions 9913
(S15E23) and 9914 (N04E72) were numbered.
IB.  Solar Activity Forecast:  Solar activity is expected to be
moderate. Region 9906 appears to be capable of M-class activity,
including an isolated major flare.
IIA.  Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field ranged from unsettled to major storm. A shock
was observed at ACE at 19/0804 UTC and was followed by an SI at
ground magnetometers (36 nT at Boulder) at 19/0836 UTC. This shock
is believed to be associated with the LDE M2/CME that occurred on 17
April.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at active to major storm levels for about the next 12
hours as the current CME passes. The field is expected to return to
quiet to unsettled conditions by the end of the 3-day forecast
period. A greater than 10 MeV proton event is possible if Region
9906 produces a major flare.
III.  Event Probabilities 20 Apr-22 Apr
Class M    50/30/30
Class X    05/01/01
Proton     05/01/01
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           19 Apr 180
Predicted   20 Apr-22 Apr  175/170/170
90 Day Mean        19 Apr 201
V.  Geomagnetic A Indices
Observed Afr/Ap 18 Apr  035/054
Estimated Afr/Ap 19 Apr  030/040
Predicted Afr/Ap 20 Apr-22 Apr  030/040-012/015-008/015
VI.  Geomagnetic Activity Probabilities 20 Apr-22 Apr
A.  Middle Latitudes
Active                60/30/10
Minor storm           30/10/05
Major-severe storm    10/05/01
B.  High Latitudes
Active                45/40/15
Minor storm           40/15/05
Major-severe storm    15/10/01