:Product: Report of Solar-Geophysical Activity
:Issued: 2024 Apr 26 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 117 Issued at 2200Z on 26 Apr 2024

IA.  Analysis of Solar Active Regions and Activity from 25/2100Z to
26/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C6 event observed at
26/0636Z from Region 3639 (N30W90). There are currently 11 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 day one (27 Apr) and likely
to be moderate on day two (28 Apr) and expected to be low with a chance
for M-class flares on day three (29 Apr).

IIA.  Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 387 km/s at 26/0116Z. Total IMF
reached 13 nT at 26/1515Z. The maximum southward component of Bz reached
-11 nT at 26/1253Z.  Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 825 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at unsettled to active levels on day one (27 Apr), quiet to active
levels on day two (28 Apr) and quiet to unsettled levels on day three
(29 Apr). Protons greater than 10 Mev have a slight chance of crossing
threshold on day one (27 Apr).

III.  Event probabilities 27 Apr-29 Apr
Class M    75/55/35
Class X    15/05/05
Proton     15/05/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           26 Apr 153
Predicted   27 Apr-29 Apr 145/135/130
90 Day Mean        26 Apr 163

V.  Geomagnetic A Indices
Observed Afr/Ap 25 Apr  003/002
Estimated Afr/Ap 26 Apr  013/018
Predicted Afr/Ap 27 Apr-29 Apr  015/018-013/015-008/010

VI.  Geomagnetic Activity Probabilities 27 Apr-29 Apr
A.  Middle Latitudes
Active                35/30/20
Minor Storm           20/15/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                10/15/15
Minor Storm           30/30/25
Major-severe storm    50/45/30