:Product: Report of Solar-Geophysical Activity
:Issued: 2026 May 16 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 136 Issued at 2200Z on 16 May 2026

IA.  Analysis of Solar Active Regions and Activity from 15/2100Z to
16/2100Z: Solar activity has been at moderate levels for the past 24
hours. There are currently 6 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares on days one, two, and three (17 May, 18 May,
19 May).

IIA.  Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic
field has been at quiet to major storm levels for the past 24 hours.
Solar wind speed reached a peak of 823 km/s at 16/0336Z. Total IMF
reached 15 nT at 15/2213Z. The maximum southward component of Bz reached
-11 nT at 15/2149Z.  Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 1420 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (17 May), unsettled to
minor storm levels on day two (18 May) and quiet to active levels on day
three (19 May).

III.  Event probabilities 17 May-19 May
Class M    40/40/40
Class X    05/05/05
Proton     05/05/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           16 May 109
Predicted   17 May-19 May 105/106/110
90 Day Mean        16 May 124

V.  Geomagnetic A Indices
Observed Afr/Ap 15 May  022/035
Estimated Afr/Ap 16 May  027/038
Predicted Afr/Ap 17 May-19 May  014/018-016/020-013/015

VI.  Geomagnetic Activity Probabilities 17 May-19 May
A.  Middle Latitudes
Active                40/40/35
Minor Storm           30/30/15
Major-severe storm    10/10/01
B.  High Latitudes
Active                05/05/15
Minor Storm           25/25/30
Major-severe storm    70/70/40