:Product: Report of Solar-Geophysical Activity
:Issued: 2023 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 2023

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.
The largest solar event of the period was a C4 event observed at
27/0546Z. There are currently 8 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares and a slight chance for an X-class flare on
day one (28 Sep) and expected to be low with a chance for M-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 529 km/s at 26/2104Z. Total IMF reached 6
nT at 27/0456Z. The maximum southward component of Bz reached -4 nT at
27/1807Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 3755 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one and two (28 Sep, 29 Sep)
and quiet to active levels on day three (30 Sep). Protons greater than
10 Mev have a slight chance of crossing threshold on day one (28 Sep).

III.  Event probabilities 28 Sep-30 Sep
Class M    35/30/30
Class X    10/05/05
Proton     10/05/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           27 Sep 156
Predicted   28 Sep-30 Sep 160/158/155
90 Day Mean        27 Sep 162

V.  Geomagnetic A Indices
Observed Afr/Ap 26 Sep  026/032
Estimated Afr/Ap 27 Sep  014/016
Predicted Afr/Ap 28 Sep-30 Sep  007/008-007/008-010/012

VI.  Geomagnetic Activity Probabilities 28 Sep-30 Sep
A.  Middle Latitudes
Active                20/15/30
Minor Storm           05/05/10
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           20/20/30
Major-severe storm    20/20/40