:Product: 1220RSGA.txt
:Issued: 2023 Dec 20 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 354 Issued at 2200Z on 20 Dec 2023

IA.  Analysis of Solar Active Regions and Activity from 19/2100Z to
20/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C8 event observed at
20/0854Z from Region 3521 (N11E03). There are currently 9 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 (21 Dec, 22 Dec,
23 Dec).

IIA.  Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 618 km/s at 19/2107Z. Total IMF reached 7
nT at 20/0027Z. The maximum southward component of Bz reached -7 nT at
20/0050Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 852 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on day one (21 Dec), quiet levels on
day two (22 Dec) and quiet to active levels on day three (23 Dec).

III.  Event probabilities 21 Dec-23 Dec
Class M    35/35/35
Class X    05/05/05
Proton     05/05/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           20 Dec 195
Predicted   21 Dec-23 Dec 190/188/186
90 Day Mean        20 Dec 149

V.  Geomagnetic A Indices
Observed Afr/Ap 19 Dec  010/008
Estimated Afr/Ap 20 Dec  013/015
Predicted Afr/Ap 21 Dec-23 Dec  007/010-005/005-010/012

VI.  Geomagnetic Activity Probabilities 21 Dec-23 Dec
A.  Middle Latitudes
Active                15/10/25
Minor Storm           05/01/10
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           15/15/20
Major-severe storm    10/10/25