Joint USAF/NOAA Report of Solar and Geophysical Activity 18 Aug 2005

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

Updated 2005 Aug 18 2204 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 230 Issued at 2200Z on 18 Aug 2005

IA. Analysis of Solar Active Regions and Activity from 17/2100Z
to 18/2100Z: Solar activity was very low. Newly numbered Region 799
(S12W56) was responsible for several B-class flares. LASCO imagery
showed a CME at 18/1654 UTC directed towards the southwest which was
likely associated with a B2 flare which occurred from Region 799 at
18/1605 UTC.

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

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field was quiet to active due to the continued
influence of a coronal hole high speed stream. Solar wind speed at
ACE has gradually decreased from approximately 700 km/s to 620 km/s.
The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled with a chance of isolated active
periods on 19 August as the coronal hole high speed stream moves out
of geoeffective position. Quiet to unsettled conditions are expected
on 20 – 21 August.

III. Event Probabilities 19 Aug-21 Aug

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

IV. Penticton 10.7 cm Flux

• Observed 18 Aug 083
• Predicted 19 Aug-21 Aug 085/085/085
• 90 Day Mean 18 Aug 093

V. Geomagnetic A Indices

• Observed Afr/Ap 17 Aug 011/018
• Estimated Afr/Ap 18 Aug 010/015
• Predicted Afr/Ap 19 Aug-21 Aug 008/010-004/007-004/007

VI. Geomagnetic Activity Probabilities 19 Aug-21 Aug

A. Middle Latitudes

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

B. High Latitudes

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