Joint USAF/NOAA Report of Solar and Geophysical Activity 21 Feb 2005

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Feb 21 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 052 Issued at 2200Z on 21 Feb 2005

IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was at very low levels. Region 735
(S09W71) was limited to minor B-class flares today. This region
underwent little change and retains the beta-gamma magnetic
classification. Region 736 (N13W63) showed an increase in penumbral
coverage over the past 24 hours and produced several minor B-class
flares. No new regions were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be at
very low to low levels. Both Region 735 and 736 have the potential
of producing isolated C-class flares.

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was at quiet to unsettled levels. The greater
than 2 MeV electron flux at geosynchronous orbit reached high levels
today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels. High latitudes may
experience isolated active conditions with the influence of a
recurrent high speed coronal hole stream beginning late on 23
February.

III. Event Probabilities 22 Feb-24 Feb

• Class M 10/10/05
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 21 Feb 095
• Predicted 22 Feb-24 Feb 095/090/085
• 90 Day Mean 21 Feb 100

V. Geomagnetic A Indices

• Observed Afr/Ap 20 Feb 006/012
• Estimated Afr/Ap 21 Feb 005/008
• Predicted Afr/Ap 22 Feb-24 Feb 007/010-007/012-010/012

VI. Geomagnetic Activity Probabilities 22 Feb-24 Feb

A. Middle Latitudes

• Active 15/15/20
• Minor storm 01/01/05
• Major-severe storm 01/01/01

B. High Latitudes

• Active 20/25/25
• Minor storm 05/10/10
• Major-severe storm 01/05/05