NOAA SEC Report of Solar-Geophysical Activity 21 May 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 May 21 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 141 Issued at 2200Z on 21 May 2001
IA.  Analysis of Solar Active Regions and Activity from  20/2100Z
to 21/2100Z:  Solar activity was low. The largest event of the period
was a C9 flare from Region 9461 (N22W06). A CME was observed from
this flare with most material expelled northward. Region 9463
(N12E31) continues its growth phase and is now an "E" type group in
excess of 500 millionths of white light areal coverage. Three new
regions were numbered today - 9466 (S02E40), 9467 (S05E55), and 9468
(N07E65).
IB.  Solar Activity Forecast:  Solar activity is expected to be at
low to moderate levels. Regions 9461 and 9463 have potential
for isolated M-class flares.
IIA.  Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was quiet to unsettled. The greater than 10 MeV
proton flux at geosynchronous has been enhanced since the M6 flare
at 20/0603UT, but is slowly returning to background levels. The
greater than 2 MeV electron flux was at moderate to high levels.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to continue at quiet to unsettled levels through day one.
Active periods are possible on day two and three due to a high speed
coronal hole effects and a possible glancing blow from a CME
observed early on 20 May.
III.  Event Probabilities 22 May-24 May
Class M    25/30/30
Class X    05/05/05
Proton     05/05/05
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           21 May 150
Predicted   22 May-24 May  155/160/165
90 Day Mean        21 May 168
V.  Geomagnetic A Indices
Observed Afr/Ap 20 May  006/010
Estimated Afr/Ap 21 May  005/008
Predicted Afr/Ap 22 May-24 May  010/012-015/020-010/012
VI.  Geomagnetic Activity Probabilities 22 May-24 May
A.  Middle Latitudes
Active                20/25/20
Minor storm           10/15/10
Major-severe storm    05/10/05
B.  High Latitudes
Active                25/35/25
Minor storm           15/25/10
Major-severe storm    05/15/05