:Product: 0421RSGA.txt
:Issued: 2024 Apr 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 112 Issued at 2200Z on 21 Apr 2024

IA.  Analysis of Solar Active Regions and Activity from 20/2100Z to
21/2100Z: Solar activity has been at moderate levels for the past 24
hours. The largest solar event of the period was a M2 event observed at
21/1514Z from Region 3638 (S18W35). There are currently 17 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be moderate
with a slight chance for an X-class flare on days one, two, and three
(22 Apr, 23 Apr, 24 Apr).

IIA.  Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic
field has been at unsettled to active levels for the past 24 hours.
Solar wind speed reached a peak of 539 km/s at 21/2029Z. Total IMF
reached 7 nT at 21/1705Z. The maximum southward component of Bz reached
-6 nT at 21/1705Z.  Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 754 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one and three (22 Apr, 24
Apr) and quiet to active levels on day two (23 Apr). Protons have a
slight chance of crossing threshold on days one, two, and three (22 Apr,
23 Apr, 24 Apr).

III.  Event probabilities 22 Apr-24 Apr
Class M    75/75/75
Class X    20/20/20
Proton     20/20/20
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 Apr 217
Predicted   22 Apr-24 Apr 215/215/200
90 Day Mean        21 Apr 161

V.  Geomagnetic A Indices
Observed Afr/Ap 20 Apr  010/012
Estimated Afr/Ap 21 Apr  015/019
Predicted Afr/Ap 22 Apr-24 Apr  009/010-011/015-009/010

VI.  Geomagnetic Activity Probabilities 22 Apr-24 Apr
A.  Middle Latitudes
Active                25/25/25
Minor Storm           05/15/05
Major-severe storm    01/05/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/25/25
Major-severe storm    30/45/30