Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 26 May 2021
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 146 Issued at 2200Z on 26 May 2021
IA. Analysis of Solar Active Regions and Activity from 25/2100Z to
26/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C3 event observed at
26/2037Z from Region 2826 (N24W60). There are currently 2 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be very low
with a chance for a C-class flares and a slight chance for an M-class
flare on days one and two (27 May, 28 May) and expected to be very low
with a slight chance for a C-class flare on day three (29 May).
IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic
field has been at quiet to minor storm levels for the past 24 hours.
Solar wind speed reached a peak of 405 km/s at 26/1813Z. Total IMF
reached 16 nT at 26/1627Z. The maximum southward component of Bz reached
-14 nT at 26/1707Z. Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 1150 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to minor storm levels on day one (27 May), quiet to
unsettled levels on day two (28 May) and quiet levels on day three (29
May).
III. Event probabilities 27 May-29 May
Class M 10/10/01
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 26 May 088
Predicted 27 May-29 May 073/072/072
90 Day Mean 26 May 076
V. Geomagnetic A Indices
Observed Afr/Ap 25 May 003/003
Estimated Afr/Ap 26 May 014/019
Predicted Afr/Ap 27 May-29 May 015/020-008/010-005/005
VI. Geomagnetic Activity Probabilities 27 May-29 May
A. Middle Latitudes
Active 35/20/10
Minor Storm 25/05/01
Major-severe storm 05/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 30/30/20
Major-severe storm 55/30/10
