:Product: 0917RSGA.txt
:Issued: 2024 Sep 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 261 Issued at 2200Z on 17 Sep 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
16/2357Z from Region 3825 (S16E20). There are currently 7 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 and two (18 Sep,
19 Sep) and expected to be low with a chance for M-class flares and a
slight chance for an X-class flare on day three (20 Sep).

IIA.  Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic
field has been at active to severe storm levels for the past 24 hours.
Solar wind speed reached a peak of 650 km/s at 17/0700Z. Total IMF
reached 19 nT at 17/0143Z. The maximum southward component of Bz reached
-18 nT at 17/0039Z.  Protons greater than 10 MeV at geosynchronous orbit
reached a peak level of 33 pfu at 17/1050Z. Electrons greater than 2 MeV
at geosynchronous orbit reached a peak level of 2394 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (18 Sep), quiet to
unsettled levels on day two (19 Sep) and quiet levels on day three (20
Sep). Protons have a chance of crossing threshold on day one (18 Sep)
and have a slight chance of crossing threshold on days two and three (19
Sep, 20 Sep).

III.  Event probabilities 18 Sep-20 Sep
Class M    55/55/50
Class X    20/15/10
Proton     30/10/10
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           17 Sep 165
Predicted   18 Sep-20 Sep 162/162/155
90 Day Mean        17 Sep 216

V.  Geomagnetic A Indices
Observed Afr/Ap 16 Sep  019/023
Estimated Afr/Ap 17 Sep  045/072
Predicted Afr/Ap 18 Sep-20 Sep  011/015-007/008-005/005

VI.  Geomagnetic Activity Probabilities 18 Sep-20 Sep
A.  Middle Latitudes
Active                35/20/10
Minor Storm           20/05/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                10/15/15
Minor Storm           25/20/15
Major-severe storm    50/25/15