NOAA SEC Report of Solar-Geophysical Activity 23 May 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 May 23 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 143 Issued at 2200Z on 23 May 2001
IA.  Analysis of Solar Active Regions and Activity from  22/2100Z
to 23/2100Z:  Solar activity was low. Isolated low C-class flares
were observed. Region 9463 (N07E04) has  doubled in size since
yesterday exceeding 750 millionths of white light areal coverage by
end of period. Despite its size, this region exhibits a fairly
simple beta configuration with no obvious complexity. Region 9468
(N05E39) also doubled in size exceeding 200 millionths with moderate
complexity. Two new regions were numbered today - 9471 (S13W02), and
9472 (N12E61).
IB.  Solar Activity Forecast:  Solar activity is expected to be low.
A very isolated chance exists for an M-class flare from Regions 9463
or 9468.
IIA.  Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field was quiet to active. The onset of a high speed
coronal hole stream occurred at approximately 23/0200Z. Solar wind
speed has gradually increased from 300 km/s to 450 km/s;
consequently, unsettled to active conditions were predominant during
the latter half of the period.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be unsettled to active through day one due to high speed
coronal hole flow. Quiet to unsettled conditions should return on
days two and three.
III.  Event Probabilities 24 May-26 May
Class M    40/40/40
Class X    05/05/05
Proton     05/05/05
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           23 May 159
Predicted   24 May-26 May  165/170/170
90 Day Mean        23 May 168
V.  Geomagnetic A Indices
Observed Afr/Ap 22 May  008/009
Estimated Afr/Ap 23 May  015/012
Predicted Afr/Ap 24 May-26 May  015/018-010/012-008/010
VI.  Geomagnetic Activity Probabilities 24 May-26 May
A.  Middle Latitudes
Active                40/25/20
Minor storm           15/10/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                50/40/30
Minor storm           25/15/10
Major-severe storm    05/05/01