:Product: Report of Solar-Geophysical Activity
:Issued: 2026 Sep 15 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 258 Issued at 2200Z on 15 Sep 2026

IA.  Analysis of Solar Active Regions and Activity from 14/2100Z to
15/2100Z: Solar activity has been at very low levels for the past 24
hours. There are currently 2 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be very low
with a chance for a C-class flares on days one, two, and three (16 Sep,
17 Sep, 18 Sep).

IIA.  Geophysical Activity Summary 14/2100Z to 15/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 814 km/s at 15/1133 UTC. Total IMF reached
17 nT at 15/1716 UTC. The maximum southward component of Bz reached -13
nT at 15/1852.  Protons greater than 10 MeV at geosynchronous orbit
reached a peak level of 3 pfu at 14/2100Z. Electrons greater than 2 MeV
at geosynchronous orbit reached a peak level of 427 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at unsettled to minor storm levels on days one and two (16 Sep, 17
Sep) and quiet to active levels on day three (18 Sep).

III.  Event probabilities 16 Sep-18 Sep
Class M    05/05/05
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           15 Sep 107
Predicted   16 Sep-18 Sep 110/105/100
90 Day Mean        15 Sep 126

V.  Geomagnetic A Indices
Observed Afr/Ap 14 Sep  008/011
Estimated Afr/Ap 15 Sep  010/014
Predicted Afr/Ap 16 Sep-18 Sep  017/020-018/022-010/012

VI.  Geomagnetic Activity Probabilities 16 Sep-18 Sep
A.  Middle Latitudes
Active                35/40/20
Minor Storm           05/10/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           20/20/20
Major-severe storm    20/20/25