Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 18 May 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 138 Issued at 2200Z on 18 May 2017

IA.  Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: 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 (19 May, 20 May, 21 May).

IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 458 km/s at 17/2148Z. Total IMF reached 9 nT at 18/1717Z. The maximum southward component of Bz reached -6 nT at 18/0338Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 149 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at active to major storm levels on day one (19 May), active to minor storm levels on day two (20 May) and quiet to active levels on day three (21 May).

III.  Event probabilities 19 May-21 May
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           18 May 072
Predicted   19 May-21 May 072/072/072
90 Day Mean        18 May 077

V.  Geomagnetic A Indices
Observed Afr/Ap 17 May  009/009
Estimated Afr/Ap 18 May  013/018
Predicted Afr/Ap 19 May-21 May  031/045-024/030-016/020

VI.  Geomagnetic Activity Probabilities 19 May-21 May
A.  Middle Latitudes
Active                30/40/20
Minor Storm           35/20/05
Major-severe storm    15/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           20/20/15
Major-severe storm    20/15/10