:Product: 0517RSGA.txt
:Issued: 2025 May 17 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 137 Issued at 2200Z on 17 May 2025

IA.  Analysis of Solar Active Regions and Activity from 16/2100Z to
17/2100Z: Solar activity has been at low levels for the past 24 hours.
There are currently 3 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 (18 May, 19 May, 20 May).

IIA.  Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at unsettled to major storm levels for the past 24 hours.
Solar wind speed reached a peak of 761 km/s at 17/1957Z. Total IMF
reached 22 nT at 17/0426Z. The maximum southward component of Bz reached
-18 nT at 17/0320Z.  Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 339 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at active to minor storm levels on days one and two (18 May, 19
May) and unsettled to active levels on day three (20 May).

III.  Event probabilities 18 May-20 May
Class M    35/35/35
Class X    10/10/10
Proton     05/05/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           17 May 117
Predicted   18 May-20 May 118/120/115
90 Day Mean        17 May 161

V.  Geomagnetic A Indices
Observed Afr/Ap 16 May  011/013
Estimated Afr/Ap 17 May  032/050
Predicted Afr/Ap 18 May-20 May  021/030-021/032-015/016

VI.  Geomagnetic Activity Probabilities 18 May-20 May
A.  Middle Latitudes
Active                40/40/35
Minor Storm           25/30/15
Major-severe storm    05/10/01
B.  High Latitudes
Active                10/10/15
Minor Storm           25/25/30
Major-severe storm    60/65/50
