:Product: 0528RSGA.txt
:Issued: 2025 May 28 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 148 Issued at 2200Z on 28 May 2025

IA.  Analysis of Solar Active Regions and Activity from 27/2100Z to
28/2100Z: Solar activity has been at low 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 and a slight chance for an X-class flare on
days one, two, and three (29 May, 30 May, 31 May).

IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 648 km/s at 28/0246Z. Total IMF reached 18
nT at 28/2040Z. The maximum southward component of Bz reached -9 nT at
27/2102Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 416 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on days one and two (29 May, 30
May) and quiet to active levels on day three (31 May). Protons have a
slight chance of crossing threshold on days one, two, and three (29 May,
30 May, 31 May).

III.  Event probabilities 29 May-31 May
Class M    50/50/50
Class X    10/10/10
Proton     10/10/10
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           28 May 144
Predicted   29 May-31 May 140/138/135
90 Day Mean        28 May 154

V.  Geomagnetic A Indices
Observed Afr/Ap 27 May  012/ 015
Estimated Afr/Ap 28 May  019/021
Predicted Afr/Ap 29 May-31 May  017/020-014/018-008/012

VI.  Geomagnetic Activity Probabilities 29 May-31 May
A.  Middle Latitudes
Active                40/40/30
Minor Storm           25/25/10
Major-severe storm    05/05/01
B.  High Latitudes
Active                10/10/15
Minor Storm           25/25/30
Major-severe storm    60/60/40
