:Product: 1217RSGA.txt
:Issued: 2025 Dec 17 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 351 Issued at 2200Z on 17 Dec 2025

IA.  Analysis of Solar Active Regions and Activity from 16/2100Z to
17/2100Z: Solar activity has been at low levels for the past 24 hours.
There are currently 5 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 (18
Dec, 19 Dec, 20 Dec).

IIA.  Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 744 km/s at 17/2030Z. Total IMF reached 8
nT at 17/1801Z. The maximum southward component of Bz reached -7 nT at
17/1241Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 1632 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on day one (18 Dec) and quiet to
unsettled levels on days two and three (19 Dec, 20 Dec).

III.  Event probabilities 18 Dec-20 Dec
Class M    15/15/15
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           17 Dec 119
Predicted   18 Dec-20 Dec 118/115/110
90 Day Mean        17 Dec 150

V.  Geomagnetic A Indices
Observed Afr/Ap 16 Dec  006/012
Estimated Afr/Ap 17 Dec  010/014
Predicted Afr/Ap 18 Dec-20 Dec  014/015-009/010-008/008

VI.  Geomagnetic Activity Probabilities 18 Dec-20 Dec
A.  Middle Latitudes
Active                35/25/20
Minor Storm           15/10/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                10/15/15
Minor Storm           25/25/25
Major-severe storm    50/35/25
