:Product: 0520RSGA.txt
:Issued: 2023 May 20 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 140 Issued at 2200Z on 20 May 2023

IA.  Analysis of Solar Active Regions and Activity from 19/2100Z to
20/2100Z: 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
20/1235Z from Region 3311 (N18E47). There are currently 8 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be moderate
with a chance for X-class flares on days one, two, and three (21 May, 22
May, 23 May).

IIA.  Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic
field has been at unsettled to major storm levels for the past 24 hours.
Solar wind speed reached a peak of 607 km/s at 20/2018Z. Total IMF
reached 20 nT at 20/0323Z. The maximum southward component of Bz reached
-17 nT at 20/0900Z.  Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 146 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on days one and two (21 May, 22 May) and
quiet to minor storm levels on day three (23 May). Protons have a slight
chance of crossing threshold on days one, two, and three (21 May, 22
May, 23 May).

III.  Event probabilities 21 May-23 May
Class M    75/75/75
Class X    35/35/35
Proton     15/15/15
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           20 May 170
Predicted   21 May-23 May 168/160/155
90 Day Mean        20 May 153

V.  Geomagnetic A Indices
Observed Afr/Ap 19 May  010/008
Estimated Afr/Ap 20 May  024/034
Predicted Afr/Ap 21 May-23 May  010/012-011/012-014/018

VI.  Geomagnetic Activity Probabilities 21 May-23 May
A.  Middle Latitudes
Active                30/30/35
Minor Storm           10/15/20
Major-severe storm    01/01/05
B.  High Latitudes
Active                15/20/15
Minor Storm           30/25/20
Major-severe storm    40/25/20