:Product: Report of Solar-Geophysical Activity
:Issued: 2026 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 2026

IA.  Analysis of Solar Active Regions and Activity from 20/2100Z to
21/2100Z: Solar activity has been at low levels for the past 24 hours.
There are currently 4 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be low with
a slight chance for an M-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 quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 603 km/s at 21/1727Z. Total IMF
reached 9 nT at 20/2154Z. The maximum southward component of Bz reached
-7 nT at 21/0003Z.  Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 4986 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one, two, and three (22 Apr,
23 Apr, 24 Apr).

III.  Event probabilities 22 Apr-24 Apr
Class M    10/10/10
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           21 Apr 112
Predicted   22 Apr-24 Apr 115/120/120
90 Day Mean        21 Apr 131

V.  Geomagnetic A Indices
Observed Afr/Ap 20 Apr  013/024
Estimated Afr/Ap 21 Apr  014/019
Predicted Afr/Ap 22 Apr-24 Apr  007/008-007/008-009/008

VI.  Geomagnetic Activity Probabilities 22 Apr-24 Apr
A.  Middle Latitudes
Active                20/20/20
Minor Storm           05/05/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/25/25
Major-severe storm    25/25/25