:Product: 1221RSGA.txt
:Issued: 2021 Dec 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 355 Issued at 2200Z on 21 Dec 2021

IA.  Analysis of Solar Active Regions and Activity from 20/2100Z to
21/2100Z: Solar activity has been at moderate levels for the past 24
hours. The largest solar event of the period was a M1 event observed at
21/1144Z from Region 2916 (S18E82). There are currently 10 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares on days one, two, and three (22 Dec, 23 Dec,
24 Dec).

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 638 km/s at 20/2225Z. Total IMF reached 6
nT at 20/2106Z. The maximum southward component of Bz reached -5 nT at
21/0049Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 962 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on day one (22 Dec) and quiet to
active levels on days two and three (23 Dec, 24 Dec).

III.  Event probabilities 22 Dec-24 Dec
Class M    25/25/25
Class X    05/05/05
Proton     05/05/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 Dec 137
Predicted   22 Dec-24 Dec 136/134/134
90 Day Mean        21 Dec 090

V.  Geomagnetic A Indices
Observed Afr/Ap 20 Dec  013/011
Estimated Afr/Ap 21 Dec  009/011
Predicted Afr/Ap 22 Dec-24 Dec  008/008-012/016-016/018

VI.  Geomagnetic Activity Probabilities 22 Dec-24 Dec
A.  Middle Latitudes
Active                25/35/35
Minor Storm           05/20/25
Major-severe storm    01/05/05
B.  High Latitudes
Active                15/10/10
Minor Storm           30/25/25
Major-severe storm    30/55/60