Joint USAF/NOAA Report of Solar and Geophysical Activity 20 Jul 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 Jul 20 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 20 Jul 2008
SDF Number 202 Issued at 2200Z on 20 Jul 2008

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity was at very low levels. Region 1000 (S12W05) remained quiet and stable.

IB. Solar Activity Forecast: Solar activity is expected to remain at very low levels.

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field was quiet. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels again today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly quiet to unsettled all three days of the forecast period (21 – 23 July) with isolated active periods possible on day three. The forecasted increase in activity is a result of a recurrent coronal hole high speed stream that is expected to rotate into a geoeffective position.

III. Event Probabilities 21 Jul-23 Jul

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

IV. Penticton 10.7 cm Flux

• Observed 20 Jul 066
• Predicted 21 Jul-23 Jul 066/066/066
• 90 Day Mean 20 Jul 067

V. Geomagnetic A Indices

• Observed Afr/Ap 19 Jul 001/003
• Estimated Afr/Ap 20 Jul 003/005
• Predicted Afr/Ap 21 Jul-23 Jul 008/008-010/010-015/015

VI. Geomagnetic Activity Probabilities 21 Jul-23 Jul

A. Middle Latitudes

• Active 15/15/45
• Minor storm 05/05/20
• Major-severe storm 01/01/05

B. High Latitudes

• Active 20/20/50
• Minor storm 05/10/20
• Major-severe storm 01/01/05