:Product: 0518RSGA.txt
:Issued: 2024 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 139 Issued at 2200Z on 18 May 2024

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 C7 event observed at
18/0538Z from Region 3679 (S08W07). There are currently 9 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is likely to be moderate
with a chance for X-class flares 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 minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 517 km/s at 17/2145Z. Total IMF
reached 11 nT at 17/2213Z. The maximum southward component of Bz reached
-9 nT at 17/2203Z.  Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 222 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on day one (19 May), quiet to minor
storm levels on day two (20 May) and unsettled to active levels on day
three (21 May). Protons have a slight chance of crossing threshold on
days one, two, and three (19 May, 20 May, 21 May).

III.  Event probabilities 19 May-21 May
Class M    55/55/55
Class X    25/25/25
Proton     10/10/10
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           18 May 194
Predicted   19 May-21 May 195/200/200
90 Day Mean        18 May 167

V.  Geomagnetic A Indices
Observed Afr/Ap 17 May  016/028
Estimated Afr/Ap 18 May  010/012
Predicted Afr/Ap 19 May-21 May  013/018-016/024-014/016

VI.  Geomagnetic Activity Probabilities 19 May-21 May
A.  Middle Latitudes
Active                35/40/30
Minor Storm           15/25/10
Major-severe storm    01/05/01
B.  High Latitudes
Active                10/05/15
Minor Storm           25/20/25
Major-severe storm    50/65/40