:Product: 0523RSGA.txt
:Issued: 2013 May 23 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
#
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 143 Issued at 2200Z on 23 May 2013

IA.  Analysis of Solar Active Regions and Activity from 22/2100Z to
23/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C3 event observed at
23/1450Z from Region 1756 (S20E27). There are currently 7 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares and a slight chance for an X-class flare on
days one, two, and three (24 May, 25 May, 26 May).

IIA.  Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
475 km/s at 23/1933Z, however ACE/SWEPAM data became suspect due to
proton contamination from the 22 May M5 flare. Total IMF reached 8 nT at
23/1656Z. The maximum southward component of Bz reached -4 nT at
23/0949Z. Protons greater than 10 MeV at geosynchronous orbit reached a
peak level of 1660 pfu at 23/0650Z. Protons greater than 100 MeV at
geosynchronous orbit reached a peak level of 2 pfu at 22/2105Z and the
event ended at 23/0745Z. Electrons greater than 2 MeV at geosynchronous
orbit were also suspect due to proton contamination.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (24 May), quiet to
active levels on day two (25 May) and quiet to unsettled levels on day
three (26 May). Protons are expected to remain above threshold on day
one (24 May), are likely to cross threshold on day two (25 May) and have
a chance of crossing threshold on day three (26 May).

III.  Event probabilities 24 May-26 May
Class M    45/45/45
Class X    15/15/15
Proton     99/70/30
PCAF       red

IV.  Penticton 10.7 cm Flux
Observed           23 May 135
Predicted   24 May-26 May 135/135/130
90 Day Mean        23 May 122

V.  Geomagnetic A Indices
Observed Afr/Ap 22 May  010/012
Estimated Afr/Ap 23 May  008/008
Predicted Afr/Ap 24 May-26 May  011/015-014/020-008/012

VI.  Geomagnetic Activity Probabilities 24 May-26 May
A.  Middle Latitudes
Active                35/35/20
Minor Storm           20/15/05
Major-severe storm    05/05/01
B.  High Latitudes
Active                10/10/15
Minor Storm           25/30/25
Major-severe storm    55/50/25