Joint USAF/NOAA Report of Solar and Geophysical Activity 21 Apr 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Apr 21 2200 UTC
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 111 Issued at 2200Z on 21 Apr 2007

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity was very low. The visible solar disk remains spotless.

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

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field was quiet.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled with possible active periods at high latitudes on 22 April due to a recurrent coronal hole high speed stream. Expect quiet to unsettled conditions on 23 – 24 April.

III. Event Probabilities 22 Apr-24 Apr

• Class M 01/01/01
• Class X 01/01/01
• Proton 01/01/01
• PCAF Green

IV. Penticton 10.7 cm Flux

• Observed 21 Apr 069
• Predicted 22 Apr-24 Apr 070/070/070
• 90 Day Mean 21 Apr 075

V. Geomagnetic A Indices

• Observed Afr/Ap 20 Apr 002/003
• Estimated Afr/Ap 21 Apr 005/010
• Predicted Afr/Ap 22 Apr-24 Apr 010/015-008/008-005/005

VI. Geomagnetic Activity Probabilities 22 Apr-24 Apr

A. Middle Latitudes

• Active 25/20/15
• Minor storm 10/10/05
• Major-severe storm 01/01/01

B. High Latitudes

• Active 35/25/25
• Minor storm 20/15/15
• Major-severe storm 05/01/01