:Product: 1218RSGA.txt
:Issued: 2025 Dec 18 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 352 Issued at 2200Z on 18 Dec 2025

IA.  Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: 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 (19
Dec, 20 Dec, 21 Dec).

IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 723 km/s at 18/0659Z. Total IMF
reached 7 nT at 17/2227Z. The maximum southward component of Bz reached
-7 nT at 17/2232Z.  Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 2693 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one and two (19 Dec, 20 Dec)
and quiet levels on day three (21 Dec).

III.  Event probabilities 19 Dec-21 Dec
Class M    15/15/15
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           18 Dec 116
Predicted   19 Dec-21 Dec 115/110/110
90 Day Mean        18 Dec 149

V.  Geomagnetic A Indices
Observed Afr/Ap 17 Dec  010/018
Estimated Afr/Ap 18 Dec  014/018
Predicted Afr/Ap 19 Dec-21 Dec  009/010-008/008-005/005

VI.  Geomagnetic Activity Probabilities 19 Dec-21 Dec
A.  Middle Latitudes
Active                25/20/10
Minor Storm           10/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/25/20
Major-severe storm    35/25/10
