Joint USAF/NOAA Report of Solar and Geophysical Activity 22 Apr 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 Apr 22 2200 UTC
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Weather Prediction Center and the U.S. Air Force.

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 113 Issued at 2200Z on 22 Apr 2008

IA. Analysis of Solar Active Regions and Activity from 21/2100Z to 22/2100Z: Solar activity was very low. No flares occurred during the past 24 hours. New Region 992 (N13W01) emerged today as a small, C-type sunspot group.

IB. Solar Activity Forecast: Solar activity is expected to be very low for the next three days (23-25 April).

IIA. Geophysical Activity Summary 21/2100Z to 22/2100Z: The geomagnetic field was quiet from the beginning of the period through about 1500Z. Since then activity has been unsettled. Real-time solar wind data from ACE indicate a possible solar sector boundary from ‘away’ orientation (positive) to ‘towards’ orientation (negative) at about 1410Z.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly unsettled with a chance for isolated active periods for the first and second days (23-24 April). The elevated activity is expected in response to a coronal hole which should be in a favorable position on those days. Activity is expected to decline to quiet to unsettled for the third day (25 April).

III. Event Probabilities 23 Apr-25 Apr

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

IV. Penticton 10.7 cm Flux

• Observed 22 Apr 071
• Predicted 23 Apr-25 Apr 075/075/075
• 90 Day Mean 22 Apr 072

V. Geomagnetic A Indices

• Observed Afr/Ap 21 Apr 003/004
• Estimated Afr/Ap 22 Apr 007/008
• Predicted Afr/Ap 23 Apr-25 Apr 012/015-012/012-007/008

VI. Geomagnetic Activity Probabilities 23 Apr-25 Apr

A. Middle Latitudes

• Active 40/40/15
• Minor storm 10/10/05
• Major-severe storm 05/05/01

B. High Latitudes

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