:Product: 0418RSGA.txt
:Issued: 2021 Apr 18 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 108 Issued at 2200Z on 18 Apr 2021

IA.  Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: Solar activity has been at very low levels for the past 24
hours. There are currently 1 numbered sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be very low
with a slight chance for a C-class flare on days one, two, and three (19
Apr, 20 Apr, 21 Apr).

IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed reached a peak of 668 km/s at 17/2136Z. Total IMF reached 6
nT at 18/0050Z. The maximum southward component of Bz reached -5 nT at
18/0337Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 14078 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on day one (19 Apr), quiet to unsettled
levels on day two (20 Apr) and quiet levels on day three (21 Apr).

III.  Event probabilities 19 Apr-21 Apr
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           18 Apr 078
Predicted   19 Apr-21 Apr 078/075/075
90 Day Mean        18 Apr 076

V.  Geomagnetic A Indices
Observed Afr/Ap 17 Apr  020/024
Estimated Afr/Ap 18 Apr  011/014
Predicted Afr/Ap 19 Apr-21 Apr  012/012-009/008-006/005

VI.  Geomagnetic Activity Probabilities 19 Apr-21 Apr
A.  Middle Latitudes
Active                40/25/15
Minor Storm           15/10/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                10/15/15
Minor Storm           25/30/20
Major-severe storm    50/40/20