:Product: Report of Solar-Geophysical Activity
:Issued: 2026 Mar 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 87 Issued at 2200Z on 28 Mar 2026

IA.  Analysis of Solar Active Regions and Activity from 27/2100Z to
28/2100Z: Solar activity has been at moderate 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 Mar, 30 Mar, 31 Mar).

IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 434 km/s at 27/2114Z. Total IMF reached 7
nT at 28/2057Z. The maximum southward component of Bz reached -7 nT at
28/2057Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 1596 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on day one (29 Mar), quiet to minor
storm levels on day two (30 Mar) and quiet to active levels on day three
(31 Mar).

III.  Event probabilities 29 Mar-31 Mar
Class M    50/50/50
Class X    10/10/10
Proton     05/05/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           28 Mar 162
Predicted   29 Mar-31 Mar 160/158/155
90 Day Mean        28 Mar 140

V.  Geomagnetic A Indices
Observed Afr/Ap 27 Mar  006/007
Estimated Afr/Ap 28 Mar  009/009
Predicted Afr/Ap 29 Mar-31 Mar  007/008-013/018-010/012

VI.  Geomagnetic Activity Probabilities 29 Mar-31 Mar
A.  Middle Latitudes
Active                20/40/30
Minor Storm           05/25/10
Major-severe storm    01/05/01
B.  High Latitudes
Active                15/10/15
Minor Storm           25/25/25
Major-severe storm    25/60/40