:Product: Report of Solar-Geophysical Activity
:Issued: 2026 Aug 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 239 Issued at 2200Z on 27 Aug 2026

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 5 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 (28 Aug, 29 Aug, 30 Aug).

IIA.  Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed
reached a peak of 274 km/s at 27/0133 UTC. Total IMF reached 5 nT at
27/1953 UTC. The maximum southward component of Bz reached 1 nT at
27/0846 UTC. Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 1732 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to major storm levels on days one and two (28 Aug, 29
Aug) and quiet to active levels on day three (30 Aug). Protons have a
slight chance of crossing threshold on days one, two, and three (28 Aug,
29 Aug, 30 Aug).

III.  Event probabilities 28 Aug-30 Aug
Class M    45/45/45
Class X    10/10/10
Proton     10/10/10
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           27 Aug 122
Predicted   28 Aug-30 Aug 122/125/120
90 Day Mean        27 Aug 131

V.  Geomagnetic A Indices
Observed Afr/Ap 26 Aug  004/003
Estimated Afr/Ap 27 Aug  005/008
Predicted Afr/Ap 28 Aug-30 Aug  024/034-019/025-014/016

VI.  Geomagnetic Activity Probabilities 28 Aug-30 Aug
A.  Middle Latitudes
Active                30/30/35
Minor Storm           35/35/10
Major-severe storm    25/15/01
B.  High Latitudes
Active                05/15/15
Minor Storm           20/20/35
Major-severe storm    75/30/35