:Product: 0421RSGA.txt
:Issued: 2025 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 111 Issued at 2200Z on 21 Apr 2025

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. 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 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 quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 745 km/s at 21/1336Z. Total IMF
reached 18 nT at 21/0733Z. The maximum southward component of Bz reached
-14 nT at 21/0803Z.  Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 452 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at unsettled to major storm levels on day one (22 Apr), quiet to
minor storm levels on day two (23 Apr) and quiet to active levels on day
three (24 Apr).

III.  Event probabilities 22 Apr-24 Apr
Class M    40/40/40
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 Apr 163
Predicted   22 Apr-24 Apr 163/160/160
90 Day Mean        21 Apr 173

V.  Geomagnetic A Indices
Observed Afr/Ap 20 Apr  011/ 14
Estimated Afr/Ap 21 Apr  028/039
Predicted Afr/Ap 22 Apr-24 Apr  020/032-016/020-014/018

VI.  Geomagnetic Activity Probabilities 22 Apr-24 Apr
A.  Middle Latitudes
Active                35/40/30
Minor Storm           40/30/15
Major-severe storm    20/10/01
B.  High Latitudes
Active                05/05/15
Minor Storm           15/20/30
Major-severe storm    80/75/45
