:Product: 0517RSGA.txt
:Issued: 2021 May 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 137 Issued at 2200Z on 17 May 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 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 and two (18 May, 19
May) and expected to be very low on day three (20 May).

IIA.  Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed
reached a peak of 433 km/s at 17/1057Z. Total IMF reached 8 nT at
17/1954Z. The maximum southward component of Bz reached -7 nT at
17/1921Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 414 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (18 May), unsettled to
active levels on day two (19 May) and quiet to active levels on day
three (20 May).

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

IV.  Penticton 10.7 cm Flux
Observed           17 May 075
Predicted   18 May-20 May 076/075/074
90 Day Mean        17 May 076

V.  Geomagnetic A Indices
Observed Afr/Ap 16 May  004/005
Estimated Afr/Ap 17 May  008/012
Predicted Afr/Ap 18 May-20 May  013/018-017/020-012/012

VI.  Geomagnetic Activity Probabilities 18 May-20 May
A.  Middle Latitudes
Active                40/30/25
Minor Storm           25/15/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                10/10/15
Minor Storm           25/25/30
Major-severe storm    60/40/30