:Product: 1231RSGA.txt
:Issued: 2025 Dec 31 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 365 Issued at 2200Z on 31 Dec 2025

IA.  Analysis of Solar Active Regions and Activity from 30/2100Z to
31/2100Z: Solar activity has been at high levels for the past 24 hours.
There are currently 7 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is likely to be moderate
with a slight chance for an X-class flare on days one, two, and three
(01 Jan, 02 Jan, 03 Jan).

IIA.  Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 616 km/s at 31/1506Z. Total IMF reached 12
nT at 31/1458Z. The maximum southward component of Bz reached -6 nT at
31/1158Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 3898 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on days one and two (01 Jan, 02
Jan) and unsettled to major storm levels on day three (03 Jan). Protons
have a chance of crossing threshold on day one (01 Jan), have a slight
chance of crossing threshold on day two (02 Jan) and have a slight
chance of crossing threshold on day three (03 Jan).

III.  Event probabilities 01 Jan-03 Jan
Class M    55/55/55
Class X    20/20/20
Proton     40/20/10
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           31 Dec 171
Predicted   01 Jan-03 Jan 170/165/160
90 Day Mean        31 Dec 147

V.  Geomagnetic A Indices
Observed Afr/Ap 30 Dec  005/008
Estimated Afr/Ap 31 Dec  007/007
Predicted Afr/Ap 01 Jan-03 Jan  014/018-014/016-028/042

VI.  Geomagnetic Activity Probabilities 01 Jan-03 Jan
A.  Middle Latitudes
Active                40/40/30
Minor Storm           30/30/40
Major-severe storm    05/05/25
B.  High Latitudes
Active                05/05/05
Minor Storm           20/20/15
Major-severe storm    65/65/85
