Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 31 January 2013 Corrected Copy


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 31 Issued at 2200Z on 31 Jan 2013

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IA. Analysis of Solar Active Regions and Activity from 30/2100Z to
31/2100Z: 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
31/0434Z from Region 1663 (S09W24). There are currently 4 numbered
sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be very low
with a chance for C-class flares on days one, two, and three (01 Feb, 02
Feb, 03 Feb).

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: 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 344 km/s at
31/2011Z. Total IMF reached 6.5 nT at 31/2045Z. The maximum southward
component of Bz reached -4.4 nT at 31/2023Z. Electrons greater than 2
MeV at geosynchronous orbit reached a peak level of 367 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on day one (01 Feb) increasing to
quiet to unsettled levels on day two (02 Feb) as a coronal hole
high-speed stream (CH HSS) becomes geoeffective. A further increase to
quiet to active levels is expected on day three (03 Feb) due to
continued CH HSS effects and a glancing blow from an earth-directed CME.

III. Event probabilities 01 Feb-03 Feb
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 31 Jan 103
Predicted 01 Feb-03 Feb 100/105/105
90 Day Mean 31 Jan 119

V. Geomagnetic A Indices
Observed Afr/Ap 30 Jan 002/001
Estimated Afr/Ap 31 Jan 002/002
Predicted Afr/Ap 01 Feb-03 Feb 005/005-007/012-012/018

VI. Geomagnetic Activity Probabilities 01 Feb-03 Feb
A. Middle Latitudes
Active 10/10/25
Minor Storm 01/01/10
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 15/20/25
Major-severe storm 10/10/35

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