Joint USAF/NOAA Report of Solar and Geophysical Activity 10 Apr 2003

SDF Number 100 Issued at 2200Z on 10 Apr 2003

IA. Analysis of Solar Active Regions and Activity from 09/2100Z
to 10/2100Z: Solar activity reached moderate levels. Rapidly growing
Region 326 (S12W91) produced an impulsive M2/1f flare at 09/2329
UTC. This event included a narrow CME as well as a weak Type II. The
region has since quietly rotated beyond the limb. New Region 334
(S08E69) rotated fully into view.

IB. Solar Activity Forecast: Solar activity is expected to be low.

IIA. Geophysical Activity Summary 09/2100Z to 10/2100Z:
The geomagnetic field was at mostly active to minor storm levels. A
high-speed solar wind stream has been buffeting the magnetosphere
all day, with speeds in the 700 km/s range. Southward IMF of 10 nT
has occurred for short periods.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to persist at active to minor storm conditions for another
24 hours. Unsettled to active conditions are anticipated the last 2
days of the interval.

III. Event Probabilities 11 Apr-13 Apr

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

IV. Penticton 10.7 cm Flux

• Observed 10 Apr 103
• Predicted 11 Apr-13 Apr 105/100/095
• 90 Day Mean 10 Apr 131

V. Geomagnetic A Indices

• Observed Afr/Ap 09 Apr 014/025
• Estimated Afr/Ap 10 Apr 020/024
• Predicted Afr/Ap 11 Apr-13 Apr 020/020-015/015-015/015

VI. Geomagnetic Activity Probabilities 11 Apr-13 Apr

A. Middle Latitudes

• Active 40/30/30
• Minor storm 25/20/20
• Major-severe storm 10/10/10

B. High Latitudes

• Active 50/40/40
• Minor storm 30/25/25
• Major-severe storm 10/10/10