:Product: Report of Solar-Geophysical Activity
:Issued: 2025 Apr 01 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 91 Issued at 2200Z on 01 Apr 2025

IA.  Analysis of Solar Active Regions and Activity from 31/2100Z to
01/2100Z: Solar activity has been at high levels for the past 24 hours.
There are currently 7 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 (02 Apr, 03
Apr, 04 Apr).

IIA.  Geophysical Activity Summary 31/2100Z to 01/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed
reached a peak of 526 km/s at 31/2142Z. Total IMF reached 14 nT at
01/1933Z. The maximum southward component of Bz reached -7 nT at
01/1357Z.  Protons greater than 10 MeV at geosynchronous orbit reached a
peak level of 146 pfu at 01/0425Z. Electrons greater than 2 MeV at
geosynchronous orbit reached a peak level of 3630 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on day one (02 Apr), quiet levels on day
two (03 Apr) and quiet to minor storm levels on day three (04 Apr).
Protons are likely to cross threshold on day one (02 Apr) and have a
chance of crossing threshold on days two and three (03 Apr, 04 Apr).

III.  Event probabilities 02 Apr-04 Apr
Class M    75/75/75
Class X    25/25/25
Proton     60/25/25
PCAF       yellow

IV.  Penticton 10.7 cm Flux
Observed           01 Apr 182
Predicted   02 Apr-04 Apr 180/176/176
90 Day Mean        01 Apr 179

V.  Geomagnetic A Indices
Observed Afr/Ap 31 Mar  008/009
Estimated Afr/Ap 01 Apr  005/006
Predicted Afr/Ap 02 Apr-04 Apr  011/012-006/005-013/018

VI.  Geomagnetic Activity Probabilities 02 Apr-04 Apr
A.  Middle Latitudes
Active                25/05/40
Minor Storm           10/01/25
Major-severe storm    01/01/05
B.  High Latitudes
Active                15/15/10
Minor Storm           25/15/25
Major-severe storm    35/10/60