Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 22 April 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 112 Issued at 2200Z on 22 Apr 2013

IA. Analysis of Solar Active Regions and Activity from 21/2100Z to
22/2100Z: Solar activity has been at moderate levels for the past 24
hours. The largest solar event of the period was a M1 event observed at
22/1029Z from Region 1726 (N13W35). There are currently 3 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
day one (23 Apr) and expected to be low with a chance for M-class flares
on days two and three (24 Apr, 25 Apr).

IIA. Geophysical Activity Summary 21/2100Z to 22/2100Z: 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 302 km/s at
21/2237Z. Total IMF reached 6 nT at 22/1009Z. The maximum southward
component of Bz reached -4 nT at 22/0125Z. Protons greater than 10 MeV
at geosynchronous orbit reached a peak level of 2 pfu at 21/2315Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on days one and two (23 Apr, 24 Apr) and
quiet to minor storm levels on day three (25 Apr). Protons greater than
10 Mev have a slight chance of crossing threshold on day one (23 Apr).

III. Event probabilities 23 Apr-25 Apr
Class M 40/35/30
Class X 15/05/05
Proton 15/05/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 22 Apr 113
Predicted 23 Apr-25 Apr 115/115/115
90 Day Mean 22 Apr 111

V. Geomagnetic A Indices
Observed Afr/Ap 21 Apr 003/003
Estimated Afr/Ap 22 Apr 004/005
Predicted Afr/Ap 23 Apr-25 Apr 008/012-011/012-015/018

VI. Geomagnetic Activity Probabilities 23 Apr-25 Apr
A. Middle Latitudes
Active 25/25/30
Minor Storm 05/05/10
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/30/30
Major-severe storm 30/30/40