:Product: 0518RSGA.txt
:Issued: 2021 May 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 138 Issued at 2200Z on 18 May 2021

IA.  Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C1 event observed at
18/0209Z from Region 2824 (N19E65). There are currently 2 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
May, 20 May, 21 May).

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 410 km/s at 18/0316Z. Total IMF reached 10
nT at 18/0142Z. The maximum southward component of Bz reached -9 nT at
18/0130Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 177 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on days one and two (19 May, 20 May) and
quiet to unsettled levels on day three (21 May).

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

IV.  Penticton 10.7 cm Flux
Observed           18 May 076
Predicted   19 May-21 May 075/074/073
90 Day Mean        18 May 076

V.  Geomagnetic A Indices
Observed Afr/Ap 17 May  006/006
Estimated Afr/Ap 18 May  012/014
Predicted Afr/Ap 19 May-21 May  015/016-012/012-008/008

VI.  Geomagnetic Activity Probabilities 19 May-21 May
A.  Middle Latitudes
Active                35/25/15
Minor Storm           15/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                10/15/15
Minor Storm           25/30/25
Major-severe storm    50/30/20