:Product: 0921RSGA.txt
:Issued: 2023 Sep 21 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 264 Issued at 2200Z on 21 Sep 2023

IA.  Analysis of Solar Active Regions and Activity from 20/2100Z to
21/2100Z: Solar activity has been at high levels for the past 24 hours.
The largest solar event of the period was a M8 event observed at
21/1254Z from Region 3435 (N08E16). There are currently 11 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, two, and three
(22 Sep, 23 Sep, 24 Sep).

IIA.  Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 474 km/s at 20/2119Z. Total IMF reached 5
nT at 21/0709Z. The maximum southward component of Bz reached -4 nT at
21/1239Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 1416 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on day one (22 Sep), unsettled to minor
storm levels on day two (23 Sep) and quiet to minor storm levels on day
three (24 Sep).

III.  Event probabilities 22 Sep-24 Sep
Class M    55/55/55
Class X    10/10/10
Proton     05/05/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 Sep 168
Predicted   22 Sep-24 Sep 162/162/165
90 Day Mean        21 Sep 161

V.  Geomagnetic A Indices
Observed Afr/Ap 20 Sep  015/020
Estimated Afr/Ap 21 Sep  008/009
Predicted Afr/Ap 22 Sep-24 Sep  011/015-016/022-018/022

VI.  Geomagnetic Activity Probabilities 22 Sep-24 Sep
A.  Middle Latitudes
Active                35/35/35
Minor Storm           15/25/20
Major-severe storm    01/05/05
B.  High Latitudes
Active                10/10/15
Minor Storm           30/25/20
Major-severe storm    55/65/30