Report of Solar and Geophysical Activity

This message is a joint product of the NOAA Space Weather Prediction Center(SWPC) and the USAF Space Weather Flight.

:Product: Report of Solar-Geophysical Activity
:Issued: 2024 Apr 19 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 110 Issued at 2200Z on 19 Apr 2024

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IA.  Analysis of Solar Active Regions and Activity from 18/2100Z to
19/2100Z: 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
19/0453Z from Region 3647 (S13E00). There are currently 14 numbered
sunspot regions on the disk.
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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
(20 Apr, 21 Apr, 22 Apr).

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IIA.  Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic
field has been at quiet to severe storm levels for the past 24 hours.
Solar wind speed reached a peak of 515 km/s at 19/2034Z. Total IMF
reached 18 nT at 19/1418Z. The maximum southward component of Bz reached
-16 nT at 19/1549Z.  Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 118 pfu.
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IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one and three (20 Apr, 22
Apr) and quiet to active levels on day two (21 Apr). Protons have a
slight chance of crossing threshold on days one, two, and three (20 Apr,
21 Apr, 22 Apr).

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III.  Event probabilities 20 Apr-22 Apr
Class M    75/75/75
Class X    20/20/20
Proton     20/20/20
PCAF       green

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IV.  Penticton 10.7 cm Flux
Observed           19 Apr 213
Predicted   20 Apr-22 Apr 220/220/215
90 Day Mean        19 Apr 161

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V.  Geomagnetic A Indices
Observed Afr/Ap 18 Apr  005/004
Estimated Afr/Ap 19 Apr  024/043
Predicted Afr/Ap 20 Apr-22 Apr  007/010-011/012-008/008

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VI.  Geomagnetic Activity Probabilities 20 Apr-22 Apr
A.  Middle Latitudes
Active                25/35/20
Minor Storm           10/15/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/30/25
Major-severe storm    35/50/25
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:NWRA: File downloaded/formatted: Fri Apr 19 22:41:22 UTC 2024