Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 26 August 2018

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast

SDF Number 238 Issued at 2200Z on 26 Aug 2018

IA.  Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: 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 and two (27 Aug, 28 Aug) and expected to be very low on day three (29 Aug).

IIA.  Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic field has been at active to severe storm levels for the past 24 hours. Solar wind speed reached a peak of 553 km/s at 26/1838Z. Total IMF reached 21 nT at 26/1227Z. The maximum southward component of Bz reached -17 nT at 26/0231Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 5893 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (27 Aug) and quiet to unsettled levels on days two and three (28 Aug, 29 Aug).

III.  Event probabilities 27 Aug-29 Aug

Class M    01/01/01

Class X    01/01/01

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           26 Aug 071

Predicted   27 Aug-29 Aug 069/069/069

90 Day Mean        26 Aug 071

V.  Geomagnetic A Indices

Observed Afr/Ap 25 Aug  012/009

Estimated Afr/Ap 26 Aug  046/078

Predicted Afr/Ap 27 Aug-29 Aug  013/016-006/008-007/008

VI.  Geomagnetic Activity Probabilities 27 Aug-29 Aug

A.  Middle Latitudes

Active                35/20/25

Minor Storm           20/05/05

Major-severe storm    05/01/01

B.  High Latitudes

Active                10/15/20

Minor Storm           25/25/30

Major-severe storm    50/30/30