Joint USAF/NOAA Report of Solar and Geophysical Activity 12 Feb 2004

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.

Updated 2004 Feb 12 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 043 Issued at 2200Z on 12 Feb 2004

IA. Analysis of Solar Active Regions and Activity from 11/2100Z
to 12/2100Z: Solar activity has been very low. X-ray flux remains
steady at background levels, with very little fluxuation. No new
regions were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be very
low. Regions 551 (S08W68) and 554 (S10E12) may produce C-class
flares.

IIA. Geophysical Activity Summary 11/2100Z to 12/2100Z:
The geomagnetic field has been at unsettled to minor storm
conditions. Solar wind speed increased to around 700 km/s during
the period, and has been steady for the past 12 hours. The greater
than 2 MeV electron flux at geosynchronous orbit reached high levels
for a brief period today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at unsettled to minor storm conditions through 13
February, under the influence of a geoeffective coronal hole high
speed solar wind stream. A decrease in geomagnetic activity is
expected 14 and 15 February as the coronal hole rotates out of
geoeffective position.

III. Event Probabilities 13 Feb-15 Feb

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

IV. Penticton 10.7 cm Flux

• Observed 12 Feb 112
• Predicted 13 Feb-15 Feb 110/110/110
• 90 Day Mean 12 Feb 12

1

• V. Geomagnetic A Indices
• Observed Afr/Ap 11 Feb 012/026
• Estimated Afr/Ap 12 Feb 012/026
• Predicted Afr/Ap 13 Feb-15 Feb 015/020-015/020-012/020

VI. Geomagnetic Activity Probabilities 13 Feb-15 Feb

A. Middle Latitudes

• Active 40/30/30
• Minor storm 20/15/15
• Major-severe storm 05/05/01

B. High Latitudes

• Active 45/45/45
• Minor storm 30/30/30
• Major-severe storm 10/10/10