:Product: 0527RSGA.txt
:Issued: 2025 May 27 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 147 Issued at 2200Z on 27 May 2025

IA.  Analysis of Solar Active Regions and Activity from 26/2100Z to
27/2100Z: 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 likely to be moderate
with a slight chance for an X-class flare on days one, two, and three
(28 May, 29 May, 30 May).

IIA.  Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 517 km/s at 27/2015Z. Total IMF reached 13
nT at 27/1919Z. The maximum southward component of Bz reached -8 nT at
27/2043Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 461 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (28 May) and quiet to
active levels on days two and three (29 May, 30 May). Protons have a
slight chance of crossing threshold on days one, two, and three (28 May,
29 May, 30 May).

III.  Event probabilities 28 May-30 May
Class M    55/55/55
Class X    15/15/15
Proton     10/10/10
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           27 May 137
Predicted   28 May-30 May 133/130/130
90 Day Mean        27 May 154

V.  Geomagnetic A Indices
Observed Afr/Ap 26 May  008/ 008
Estimated Afr/Ap 27 May  013/015
Predicted Afr/Ap 28 May-30 May  018/025-015/016-009/012

VI.  Geomagnetic Activity Probabilities 28 May-30 May
A.  Middle Latitudes
Active                40/35/30
Minor Storm           30/15/10
Major-severe storm    05/01/01
B.  High Latitudes
Active                10/10/15
Minor Storm           25/30/30
Major-severe storm    65/50/40
