Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 February 2013


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 52 Issued at 2200Z on 21 Feb 2013

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to
21/2100Z: 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
21/0505Z from Region 1678 (N10W66). There are currently 5 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares and a slight chance for an X-class flare on
days one and two (22 Feb, 23 Feb) and expected to be very low with a
chance for a C-class flares and a slight chance for an M-class flare on
day three (24 Feb).

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: 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 454 km/s at
21/0100Z. Total IMF reached 9 nT at 21/0432Z. The maximum southward
component of Bz reached -7 nT at 21/0026Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on days one and two (22 Feb, 23 Feb)
and quiet levels on day three (24 Feb). Protons greater than 10 Mev have
a slight chance of crossing threshold on days one and two (22 Feb, 23
Feb).

III. Event probabilities 22 Feb-24 Feb
Class M 40/40/10
Class X 10/10/01
Proton 10/10/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 21 Feb 109
Predicted 22 Feb-24 Feb 105/105/100
90 Day Mean 21 Feb 115

V. Geomagnetic A Indices
Observed Afr/Ap 20 Feb 006/006
Estimated Afr/Ap 21 Feb 005/006
Predicted Afr/Ap 22 Feb-24 Feb 007/008-010/010-007/008

VI. Geomagnetic Activity Probabilities 22 Feb-24 Feb
A. Middle Latitudes
Active 15/20/15
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/20/15
Minor Storm 25/30/20
Major-severe storm 25/25/20

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