:Product: 0918RSGA.txt
:Issued: 2021 Sep 18 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 261 Issued at 2200Z on 18 Sep 2021

IA.  Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C2 event observed at
18/0827Z from Region 2871 (S28E73). There are currently 1 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 (19 Sep,
20 Sep, 21 Sep).

IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 426 km/s at 18/0408Z. Total IMF
reached 15 nT at 17/2125Z. The maximum southward component of Bz reached
-5 nT at 18/0738Z.  Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 179 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one and three (19 Sep, 21
Sep) and quiet levels on day two (20 Sep).

III.  Event probabilities 19 Sep-21 Sep
Class M    05/05/05
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           18 Sep 074
Predicted   19 Sep-21 Sep 076/076/076
90 Day Mean        18 Sep 082

V.  Geomagnetic A Indices
Observed Afr/Ap 17 Sep  019/021
Estimated Afr/Ap 18 Sep  010/011
Predicted Afr/Ap 19 Sep-21 Sep  006/008-006/005-007/008

VI.  Geomagnetic Activity Probabilities 19 Sep-21 Sep
A.  Middle Latitudes
Active                20/10/20
Minor Storm           05/01/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                20/15/20
Minor Storm           30/20/30
Major-severe storm    25/20/25