Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 25 August 2018

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast

SDF Number 237 Issued at 2200Z on 25 Aug 2018

IA.  Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 2 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is expected to be very low

with a slight chance for a C-class flare on days one, two, and three (26 Aug, 27 Aug, 28 Aug).

IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 463 km/s at 25/1304Z. Total IMF reached 15 nT at 25/2028Z. The maximum southward component of Bz reached -11 nT at 25/2028Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1929 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (26 Aug) and quiet levels on days two and three (27 Aug, 28 Aug).

III.  Event probabilities 26 Aug-28 Aug

Class M    01/01/01

Class X    01/01/01

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           25 Aug 072

Predicted   26 Aug-28 Aug 072/072/072

90 Day Mean        25 Aug 071

V.  Geomagnetic A Indices

Observed Afr/Ap 24 Aug  007/007

Estimated Afr/Ap 25 Aug  006/007

Predicted Afr/Ap 26 Aug-28 Aug  009/010-006/005-006/005

VI.  Geomagnetic Activity Probabilities 26 Aug-28 Aug

A.  Middle Latitudes

Active                30/15/15

Minor Storm           10/05/05

Major-severe storm    01/01/01

B.  High Latitudes

Active                15/15/15

Minor Storm           30/20/20

Major-severe storm    40/20/20