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Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 107 Issued at 2200Z on 17 Apr 2023

By Keith Cowing
Status Report
NOAA SWPC
April 17, 2023
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 107 Issued at 2200Z on 17 Apr 2023
space weather
NOAA SWPC

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 C7 event observed at 17/0633Z from Region 3281 (S22E14). There are currently 9 numbered sunspot regions on the disk

IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and 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 levels for the past 24 hours. Solar wind speed reached a peak of 532 km/s at 17/1637Z. Total IMF reached 9 nT at 17/1144Z. The maximum southward component of Bz reached -8 nT at 17/1144Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 141 pfu

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one, two, and three (18 Apr, 19 Apr, 20 Apr).

III. Event probabilities 18 Apr-20 Apr
Class M 45/45/45
Class X 10/10/10
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 17 Apr 167
Predicted 18 Apr-20 Apr 170/168/168
90 Day Mean 17 Apr 163

V. Geomagnetic A Indices
Observed Afr/Ap 16 Apr 004/005
Estimated Afr/Ap 17 Apr 005/005
Predicted Afr/Ap 18 Apr-20 Apr 006/005-005/005-005/005

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

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