:Product: 1221RSGA.txt
:Issued: 2023 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 2023

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 M4 event observed at
21/0538Z from Region 3519 (S12W72). There are currently 8 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 unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 440 km/s at 21/2136Z.  Electrons greater
than 2 MeV at geosynchronous orbit reached a peak level of 1273 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on day one (22 Dec), quiet to active levels on day
two (23 Dec) and quiet to unsettled levels on day three (24 Dec).

III.  Event probabilities 22 Dec-24 Dec
Class M    40/40/40
Class X    05/05/05
Proton     05/05/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 Dec 194
Predicted   22 Dec-24 Dec 194/190/190
90 Day Mean        21 Dec 149

V.  Geomagnetic A Indices
Observed Afr/Ap 20 Dec  007/009
Estimated Afr/Ap 21 Dec  004/005
Predicted Afr/Ap 22 Dec-24 Dec  005/005-010/012-008/008

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