:Product: 0418RSGA.txt
:Issued: 2024 Apr 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 109 Issued at 2200Z on 18 Apr 2024

IA.  Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: Solar activity has been at moderate levels for the past 24
hours. The largest solar event of the period was a M2 event observed at
18/0248Z from Region 3638 (S18E03). There are currently 14 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be moderate
with a slight chance for an X-class flare on days one, two, and three
(19 Apr, 20 Apr, 21 Apr).

IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed
reached a peak of 530 km/s at 18/0613Z. Total IMF reached 9 nT at
17/2308Z. The maximum southward component of Bz reached -3 nT at
18/2041Z.  Electrons greater than 2 MeV at geosynchronous orbit reached
a peak level of 135 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on day one (19 Apr), quiet to unsettled levels on
day two (20 Apr) and quiet to active levels on day three (21 Apr).
Protons have a slight chance of crossing threshold on days one, two, and
three (19 Apr, 20 Apr, 21 Apr).

III.  Event probabilities 19 Apr-21 Apr
Class M    75/75/75
Class X    20/20/20
Proton     20/20/20
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           18 Apr 227
Predicted   19 Apr-21 Apr 225/220/220
90 Day Mean        18 Apr 160

V.  Geomagnetic A Indices
Observed Afr/Ap 17 Apr  008/007
Estimated Afr/Ap 18 Apr  005/006
Predicted Afr/Ap 19 Apr-21 Apr  007/006-007/010-011/012

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