Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 September 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 263 Issued at 2200Z on 20 Sep 2013

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to
20/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C3 event observed at
20/1153Z from Region 1850 (N09E62). There are currently 6 numbered
sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be low on days
one, two, and three (21 Sep, 22 Sep, 23 Sep).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: 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 569 km/s at
19/2253Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 2939 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on days one and two (21 Sep, 22 Sep) and quiet to
unsettled levels on day three (23 Sep).

III. Event probabilities 21 Sep-23 Sep
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Sep 109
Predicted 21 Sep-23 Sep 115/120/115
90 Day Mean 20 Sep 111

V. Geomagnetic A Indices
Observed Afr/Ap 19 Sep 014/013
Estimated Afr/Ap 20 Sep 006/007
Predicted Afr/Ap 21 Sep-23 Sep 005/005-005/005-008/002

VI. Geomagnetic Activity Probabilities 21 Sep-23 Sep
A. Middle Latitudes
Active 05/05/10
Minor Storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 15/15/25
Major-severe storm 05/05/10