Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 19 August 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 231 Issued at 2200Z on 19 Aug 2013

IA. Analysis of Solar Active Regions and Activity from 18/2100Z to
19/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C2 event observed at
19/0920Z from Region 1817 (S19W88). There are currently 10 numbered
sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares on days one, two, and three (20 Aug, 21 Aug,
22 Aug).

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, reached a peak speed of 550km/s at
18/2231Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 6050 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on day one (20 Aug), unsettled to
active levels on day two (21 Aug) and quiet to active levels on day
three (22 Aug). Protons greater than 10 Mev have a slight chance of
crossing threshold on day one (20 Aug).

III. Event probabilities 20 Aug-22 Aug
Class M 25/25/25
Class X 05/05/05
Proton 10/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 19 Aug 128
Predicted 20 Aug-22 Aug 125/120/115
90 Day Mean 19 Aug 113

V. Geomagnetic A Indices
Observed Afr/Ap 18 Aug 008/007
Estimated Afr/Ap 19 Aug 006/006
Predicted Afr/Ap 20 Aug-22 Aug 011/014-014/018-014/012

VI. Geomagnetic Activity Probabilities 20 Aug-22 Aug
A. Middle Latitudes
Active 10/25/20
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 20/20/20
Minor Storm 25/35/35
Major-severe storm 20/30/30