:Product: Report of Solar-Geophysical Activity
:Issued: 2021 Apr 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 106 Issued at 2200Z on 16 Apr 2021

IA.  Analysis of Solar Active Regions and Activity from 15/2100Z to
16/2100Z: Solar activity has been at very 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 very low
with a chance for a C-class flares on days one, two, and three (17 Apr,
18 Apr, 19 Apr).

IIA.  Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 490 km/s at 16/1213Z. Total IMF reached 13
nT at 16/1558Z. The maximum southward component of Bz reached -10 nT at
16/1806Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 134 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (17 Apr) and quiet to
active levels on days two and three (18 Apr, 19 Apr).

III.  Event probabilities 17 Apr-19 Apr
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           16 Apr 077
Predicted   17 Apr-19 Apr 078/078/078
90 Day Mean        16 Apr 076

V.  Geomagnetic A Indices
Observed Afr/Ap 15 Apr  011/010
Estimated Afr/Ap 16 Apr  016/020
Predicted Afr/Ap 17 Apr-19 Apr  015/020-015/018-011/012

VI.  Geomagnetic Activity Probabilities 17 Apr-19 Apr
A.  Middle Latitudes
Active                35/35/35
Minor Storm           25/15/15
Major-severe storm    05/01/01
B.  High Latitudes
Active                10/10/10
Minor Storm           25/25/25
Major-severe storm    65/50/50