:Product: Report of Solar-Geophysical Activity
:Issued: 2026 Sep 27 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 270 Issued at 2200Z on 27 Sep 2026

IA.  Analysis of Solar Active Regions and Activity from 26/2100Z to
27/2100Z: Solar activity has been at low levels for the past 24 hours.
There are currently 4 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is likely to be low with a
slight chance for an M-class flare on day one (28 Sep) and expected to
be very low with a chance for a C-class flares on days two and three (29
Sep, 30 Sep).

IIA.  Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 477 km/s at 26/2142Z. Total IMF reached 5
nT at 26/2103Z. The maximum southward component of Bz reached -4 nT at
27/0618Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 3060 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on days one, two, and three (28 Sep, 29 Sep, 30
Sep).

III.  Event probabilities 28 Sep-30 Sep
Class M    10/05/05
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           27 Sep 097
Predicted   28 Sep-30 Sep 098/100/105
90 Day Mean        27 Sep 121

V.  Geomagnetic A Indices
Observed Afr/Ap 26 Sep  011/013
Estimated Afr/Ap 27 Sep  010/010
Predicted Afr/Ap 28 Sep-30 Sep  006/005-006/005-006/005

VI.  Geomagnetic Activity Probabilities 28 Sep-30 Sep
A.  Middle Latitudes
Active                05/10/10
Minor Storm           01/01/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           15/15/25
Major-severe storm    10/15/20