Joint USAF/NOAA Report of Solar and Geophysical Activity 18 Jul 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 Jul 18 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 200 Issued at 2200Z on 18 Jul 2008

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity was at very low levels. New Region 1000 (S13E24) was numbered during the period.

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

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field was at mostly quiet levels. Solar wind speed, as measured at the ACE spacecraft, continued its gradual decrease in velocities from about 460 km/s at the beginning of the period, to about 350 km/s by forecast issue time. 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 for the next three days (19 – 21 July).

III. Event Probabilities 19 Jul-21 Jul

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

IV. Penticton 10.7 cm Flux

• Observed 18 Jul 067
• Predicted 19 Jul-21 Jul 066/066/066
• 90 Day Mean 18 Jul 066

V. Geomagnetic A Indices

• Observed Afr/Ap 17 Jul 003/005
• Estimated Afr/Ap 18 Jul 005/005
• Predicted Afr/Ap 19 Jul-21 Jul 005/005-005/005-005/005

VI. Geomagnetic Activity Probabilities 19 Jul-21 Jul

A. Middle Latitudes

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

B. High Latitudes

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