:Product: 0521RSGA.txt
:Issued: 2013 May 21 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 141 Issued at 2200Z on 21 May 2013

IA.  Analysis of Solar Active Regions and Activity from 20/2100Z to
21/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C1 event observed at
21/0012Z from Region 1751 (S23W57). 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 (22 May, 23 May, 24 May).

IIA.  Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, reached a peak speed of 570 km/s at
21/1900Z. Total IMF reached 6 nT at 21/1855Z. The maximum southward
component of Bz reached -5 nT at 21/0515Z. Protons greater than 10 MeV
at geosynchronous orbit reached a peak level of 2 pfu at 20/2145Z.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one and three (22 May, 24
May) and unsettled to active levels on day two (23 May). Protons have a
slight chance of crossing threshold on days one, two, and three (22 May,
23 May, 24 May).

III.  Event probabilities 22 May-24 May
Class M    50/50/50
Class X    20/20/20
Proton     20/20/20
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 May 125
Predicted   22 May-24 May 120/120/125
90 Day Mean        21 May 121

V.  Geomagnetic A Indices
Observed Afr/Ap 20 May  006/008
Estimated Afr/Ap 21 May  007/008
Predicted Afr/Ap 22 May-24 May  011/012-012/015-007/008

VI.  Geomagnetic Activity Probabilities 22 May-24 May
A.  Middle Latitudes
Active                20/30/15
Minor Storm           05/10/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/30/25
Major-severe storm    30/40/20