:Product: 0521RSGA.txt
:Issued: 2021 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 2021

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 C4 event observed at
21/1928Z from Region 2824 (N20E27). There are currently 1 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be very low
with a chance for a C-class flares 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 to active levels for the past 24 hours. Solar
wind speed reached a peak of 598 km/s at 21/0541Z.  Electrons greater
than 2 MeV at geosynchronous orbit reached a peak level of 819 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on day one (22 May) and quiet levels
on days two and three (23 May, 24 May).

III.  Event probabilities 22 May-24 May
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 May 074
Predicted   22 May-24 May 075/075/075
90 Day Mean        21 May 076

V.  Geomagnetic A Indices
Observed Afr/Ap 20 May  017/019
Estimated Afr/Ap 21 May  008/010
Predicted Afr/Ap 22 May-24 May  008/008-006/005-006/005

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