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

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 79 Issued at 2200Z on 20 Mar 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 C5 event observed at
20/0102Z from Region 1698 (S19, L=119). There are currently 5 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low with
a slight chance for an M-class flare on day one (21 Mar) and likely to
be low with a slight chance for an M-class flare on day two (22 Mar) and
expected to be very low with a chance for a C-class flares on day three
(23 Mar).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
711 km/s at 20/1711Z. Total IMF reached 11 nT at 20/1858Z. The maximum
southward component of Bz reached -7 nT at 20/1453Z. Electrons greater
than 2 MeV at geosynchronous orbit reached a peak level of 1516 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on day one (21 Mar) and quiet to
unsettled levels on days two and three (22 Mar, 23 Mar).

III. Event probabilities 21 Mar-23 Mar
Class M 15/10/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Mar 108
Predicted 21 Mar-23 Mar 105/105/100
90 Day Mean 20 Mar 116

V. Geomagnetic A Indices
Observed Afr/Ap 19 Mar 004/003
Estimated Afr/Ap 20 Mar 007/007
Predicted Afr/Ap 21 Mar-23 Mar 008/010-007/008-008/008

VI. Geomagnetic Activity Probabilities 21 Mar-23 Mar
A. Middle Latitudes
Active 20/15/15
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 20/15/15
Minor Storm 35/20/20
Major-severe storm 30/20/20