:Product: 0417RSGA.txt
:Issued: 2024 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 108 Issued at 2200Z on 17 Apr 2024

IA.  Analysis of Solar Active Regions and Activity from 16/2100Z to
17/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C9 event observed at
17/2004Z from Region 3638 (S17E15). There are currently 12 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is likely to be moderate
with a slight chance for an X-class flare 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 quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 505 km/s at 16/2135Z. Total IMF
reached 10 nT at 16/2101Z. The maximum southward component of Bz reached
-9 nT at 16/2101Z.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (18 Apr) and quiet to
unsettled levels on days two and three (19 Apr, 20 Apr). Protons have a
slight chance of crossing threshold on days one, two, and three (18 Apr,
19 Apr, 20 Apr).

III.  Event probabilities 18 Apr-20 Apr
Class M    65/65/65
Class X    10/15/10
Proton     10/10/10
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           17 Apr 217
Predicted   18 Apr-20 Apr 210/200/190
90 Day Mean        17 Apr 160

V.  Geomagnetic A Indices
Observed Afr/Ap 16 Apr  017/030
Estimated Afr/Ap 17 Apr  008/009
Predicted Afr/Ap 18 Apr-20 Apr  015/020-010/010-007/010

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