Joint USAF/NOAA Report of Solar and Geophysical Activity 19 Apr 2004

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

Updated 2004 Apr 19 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 110 Issued at 2200Z on 19 Apr 2004

IA. Analysis of Solar Active Regions and Activity from 18/2100Z
to 19/2100Z: Solar activity has been low. Region 596 (S09E44) has
produced two C-class events in the last 24 hours. This region has
shown some minor mixing along with significant growth in both area
and sunspot count.

IB. Solar Activity Forecast: Solar activity is expected to be low.
Region 596 is expected to produce additional C-class flares with a
slight chance for an isolated M-class event.

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field has been quiet to unsettled.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels.

III. Event Probabilities 20 Apr-22 Apr

• Class M 20/20/20
• Class X 05/05/05
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 19 Apr 113
• Predicted 20 Apr-22 Apr 115/120/120
• 90 Day Mean 19 Apr 107

V. Geomagnetic A Indices

• Observed Afr/Ap 18 Apr 006/011
• Estimated Afr/Ap 19 Apr 006/010
• Predicted Afr/Ap 20 Apr-22 Apr 005/010-005/010-010/010

VI. Geomagnetic Activity Probabilities 20 Apr-22 Apr

A. Middle Latitudes

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

B. High Latitudes

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