:Product: 20010406RSGA.txt
:Issued: 2001 Apr 06 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 096 Issued at 2200Z on 06 Apr 2001
IA.  Analysis of Solar Active Regions and Activity from  05/2100Z
to 06/2100Z:  Solar activity has been high during the past 24 hours.
Region 9415 (S21E33) produced an X5/Sf flare at 1921Z (Please note
that the optical class could only be measured well after the x-ray
flare maximum due to weather hampering observations). Coronagraph
observations from SOHO/LASCO showed a CME associated with this event
just entering the C2 field of view at 1930Z. Region 9415 is the
dominant region on the disk with 820 millionths area in an Eko,
beta-gamma-delta configuration. The only other solar flares of note
today were a few C-class subflares. Coronagraph data also showed
that yesterday's CME, associated with the long-duration M5 event,
could be classified as a full-halo event. Nonetheless the sequence
of images give the impression that the center of the CME is not
headed directly at the Earth. Note that today's 10.7 cm flux had to
be estimated from the morning reading because intense solar radio
burst activity interfered with the normal noontime reading.
IB.  Solar Activity Forecast:  Solar activity is expected to be
moderate to high during the next three days. Region 9415 is clearly
the dominant region on the disk to watch for energetic flare
activity, although regions 9417 and 9418 might possibly contribute a
low-level M-class event.
IIA.  Geophysical Activity Summary 05/2100Z to 06/2100Z:
The geomagnetic field was mostly quiet to unsettled during the past
24 hours. Solar wind speeds continue to decline and solar wind
density remains low. The greater than 10 MeV proton event continued
to decline during the past 24 hours. As of 06/2100Z the fluxes were
fluctuating below and above the threshold of 10 PFU, with a reading
of 10.2 PFU at 2100Z.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be unsettled for the next 24 hours. An increase to
active levels is expected on the second and third days as a response
to a glancing blow from the halo CME associated with yesterday's M5
flare and possible additional influence from the CME associated with
today's X5 event. There is a fair chance for an increase in the
greater than 10 MeV proton fluxes sometime in the next 24 hours in
response to today's X5 event as well, although the fluxes are likely
to increase rather gradually with peak fluxes in the low 100's of
PFU, and the spectrum will probably be relatively soft.
III.  Event Probabilities 07 Apr-09 Apr
Class M    80/80/80
Class X    25/25/25
Proton     60/25/25
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           06 Apr 192
Predicted   07 Apr-09 Apr  200/195/190
90 Day Mean        06 Apr 167
V.  Geomagnetic A Indices
Observed Afr/Ap 05 Apr  011/019
Estimated Afr/Ap 06 Apr  012/015
Predicted Afr/Ap 07 Apr-09 Apr  012/012-025/025-025/025
VI.  Geomagnetic Activity Probabilities 07 Apr-09 Apr
A.  Middle Latitudes
Active                20/35/35
Minor storm           10/20/20
Major-severe storm    05/25/30
B.  High Latitudes
Active                25/40/40
Minor storm           15/25/25
Major-severe storm    05/15/30