:Product: Report of Solar-Geophysical Activity
:Issued: 2025 Oct 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 290 Issued at 2200Z on 17 Oct 2025

IA.  Analysis of Solar Active Regions and Activity from 16/2100Z to
17/2100Z: Solar activity has been at high levels for the past 24 hours.
There are currently 8 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 and two (18 Oct,
19 Oct) and expected to be low with a chance for M-class flares on day
three (20 Oct).

IIA.  Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 440 km/s at 16/2119Z. Total IMF reached 13
nT at 17/1025Z. The maximum southward component of Bz reached -8 nT at
17/0935Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 3331 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on days one and two (18 Oct, 19 Oct) and
unsettled to active levels on day three (20 Oct). Protons greater than
10 Mev have a slight chance of crossing threshold on days one and two
(18 Oct, 19 Oct).

III.  Event probabilities 18 Oct-20 Oct
Class M    60/60/40
Class X    15/15/05
Proton     10/10/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           17 Oct 164
Predicted   18 Oct-20 Oct 165/155/160
90 Day Mean        17 Oct 154

V.  Geomagnetic A Indices
Observed Afr/Ap 16 Oct  003/004
Estimated Afr/Ap 17 Oct  013/016
Predicted Afr/Ap 18 Oct-20 Oct  013/016-012/012-012/014

VI.  Geomagnetic Activity Probabilities 18 Oct-20 Oct
A.  Middle Latitudes
Active                35/35/35
Minor Storm           15/10/10
Major-severe storm    01/01/01
B.  High Latitudes
Active                10/15/10
Minor Storm           25/30/30
Major-severe storm    50/45/45