Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 18 August 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 230 Issued at 2200Z on 18 Aug 2013

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C1 event observed at
18/1131Z. There are currently 9 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 (19 Aug, 20 Aug,
21 Aug).

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: 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 650 km/s at
17/2126Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 4650 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on day one (19 Aug), quiet to active levels on day
two (20 Aug) and unsettled to active levels on day three (21 Aug).
Protons have a chance of crossing threshold on days one, two, and three
(19 Aug, 20 Aug, 21 Aug).

III. Event probabilities 19 Aug-21 Aug
Class M 25/25/25
Class X 05/05/05
Proton 25/25/25
PCAF green

IV. Penticton 10.7 cm Flux
Observed 18 Aug 126
Predicted 19 Aug-21 Aug 130/125/120
90 Day Mean 18 Aug 113

V. Geomagnetic A Indices
Observed Afr/Ap 17 Aug 009/008
Estimated Afr/Ap 18 Aug 006/006
Predicted Afr/Ap 19 Aug-21 Aug 006/005-010/018-018/025

VI. Geomagnetic Activity Probabilities 19 Aug-21 Aug
A. Middle Latitudes
Active 15/25/45
Minor Storm 01/05/15
Major-severe storm 01/01/05
B. High Latitudes
Active 20/20/10
Minor Storm 35/35/35
Major-severe storm 25/30/55