Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 051 Issued at 2200Z on 20 Feb 2005
IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity decreased to very low levels. A long
duration B-class flare was observed at 20/1628Z from just beyond the
solar west limb. This event is believed to be from Region 732 (N08
L=188) which rotated out of view on 18 February. Region 735
(S09W58) has changed little since yesterday and remains a magnetic
beta-gamma group. Region 736 (N13W50) is a weak beta magnetic
region that was numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be at
very low to low levels. Region 735 continues to show enough
complexity to possibly produce isolated C-class flare activity.
IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was at predominantly quiet to unsettled levels.
An isolated active period did occur between 20/2400 and 0300Z that
appears to be due to a recurrent high speed coronal hole stream.
The coronal hole has been waning throughout the period and current
solar wind speeds have dropped to near 400 km/s. The greater than 2
MeV electron flux at geosynchronous orbit reached high levels again
today.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at predominantly quiet to unsettled levels throughout
the period.
III. Event Probabilities 21 Feb-23 Feb
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 20 Feb 096
Predicted 21 Feb-23 Feb 095/095/090
90 Day Mean 20 Feb 101
V. Geomagnetic A Indices
Observed Afr/Ap 19 Feb 008/014
Estimated Afr/Ap 20 Feb 006/010
Predicted Afr/Ap 21 Feb-23 Feb 005/005-007/010-007/012
VI. Geomagnetic Activity Probabilities 21 Feb-23 Feb
A. Middle Latitudes
Active 15/15/15
Minor storm 01/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/20/25
Minor storm 05/05/05
Major-severe storm 01/01/01
73 & GUD DX,
Thomas F. Giella, KN4LF
Retired Space & Atmospheric Weather Forecaster
Plant City, FL, USA
Grid Square EL87WX
Lat & Long 27 58 33.6397 N 82 09 52.4052 W
kn4lf@arrl.net
Contesting Propagation eReflector:
http://lists.contesting.com/mailman/listinfo/propagation
HC-DX Propagation Channel:
http://www.hard-core-dx.com/index.php?topic=Propagation
KN4LF Daily Solar Space Weather & Geomagnetic Data Archive:
http://www.kn4lf.com/kn4lf5.htm
KN4LF Daily LF/MF/HF Radio Propagation Outlook:
http://www.kn4lf.com/kn4lf6.htm
KN4LF HF/MF Radio Propagation Theory Notes: http://www.kn4lf.com/kn4lf8.htm
KN4LF Amateur & SWL Radio History: http://www.kn4lf.com/index.htm
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