:Product: 1220RSGA.txt
:Issued: 2025 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 2025

IA.  Analysis of Solar Active Regions and Activity from 19/2100Z to
20/2100Z: Solar activity has been at moderate levels for the past 24
hours. There are currently 6 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be low with
a slight chance for an M-class flare 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 levels for the past 24 hours. Solar wind speed
reached a peak of 511 km/s at 19/2100Z. Total IMF reached 5 nT at
20/1752Z. The maximum southward component of Bz reached -3 nT at
20/1236Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 7317 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on day one (21 Dec), quiet to minor storm levels
on day two (22 Dec) and unsettled to minor storm levels on day three (23
Dec).

III.  Event probabilities 21 Dec-23 Dec
Class M    10/10/20
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           20 Dec 120
Predicted   21 Dec-23 Dec 120/120/125
90 Day Mean        20 Dec 148

V.  Geomagnetic A Indices
Observed Afr/Ap 19 Dec  004/006
Estimated Afr/Ap 20 Dec  006/006
Predicted Afr/Ap 21 Dec-23 Dec  005/005-015/022-022/030

VI.  Geomagnetic Activity Probabilities 21 Dec-23 Dec
A.  Middle Latitudes
Active                10/35/35
Minor Storm           01/30/30
Major-severe storm    01/10/10
B.  High Latitudes
Active                15/10/05
Minor Storm           20/25/20
Major-severe storm    10/65/70
