:Product: 0417RSGA.txt
:Issued: 2021 Apr 17 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 107 Issued at 2200Z on 17 Apr 2021

IA.  Analysis of Solar Active Regions and Activity from 16/2100Z to
17/2100Z: Solar activity has been at very low levels for the past 24
hours. There are currently 2 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 (18 Apr,
19 Apr, 20 Apr).

IIA.  Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at unsettled to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 612 km/s at 17/0527Z. Total IMF
reached 12 nT at 16/2217Z. The maximum southward component of Bz reached
-10 nT at 16/2158Z.  Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 1092 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on days one and two (18 Apr, 19 Apr) and
quiet to unsettled levels on day three (20 Apr).

III.  Event probabilities 18 Apr-20 Apr
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           17 Apr 075
Predicted   18 Apr-20 Apr 078/078/075
90 Day Mean        17 Apr 076

V.  Geomagnetic A Indices
Observed Afr/Ap 16 Apr  015/019
Estimated Afr/Ap 17 Apr  020/030
Predicted Afr/Ap 18 Apr-20 Apr  012/016-010/012-009/008

VI.  Geomagnetic Activity Probabilities 18 Apr-20 Apr
A.  Middle Latitudes
Active                35/35/20
Minor Storm           15/15/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                10/10/20
Minor Storm           25/25/25
Major-severe storm    50/50/25