Joint USAF/NOAA Report of Solar and Geophysical Activity 17 May 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 May 17 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 137 Issued at 2200Z on 17 May 2007

IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity decreased to very low levels. Region 956 (N02E21) was limited to the production of multiple B-class flares during the past 24 hours. The sunspot area and magnetic complexity underwent further enhancement today. Region analysis continues to depict a Dkc beta-gamma-delta sunspot group. Regions 955 (S09W92) and 957 (S04W47) were spotless over the past 24 hours. No new regions were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be at low levels. There is a slight chance of an isolated M-class flare from Region 956.

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field was at predominantly quiet levels.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at predominantly quiet levels on 17 May. Predominantly unsettled to active conditions with isolated minor storm periods are possible on 19 and 20 May, due to a recurrent coronal hole high speed stream.

III. Event Probabilities 18 May-20 May

• Class M 25/25/25
• Class X 05/05/05
• Proton 01/01/05
• PCAF Green

IV. Penticton 10.7 cm Flux

• Observed 17 May 077
• Predicted 18 May-20 May 075/075/075
• 90 Day Mean 17 May 074

V. Geomagnetic A Indices

• Observed Afr/Ap 16 May 003/004
• Estimated Afr/Ap 17 May 005/005
• Predicted Afr/Ap 18 May-20 May 005/005-010/010-010/020

VI. Geomagnetic Activity Probabilities 18 May-20 May

A. Middle Latitudes

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

B. High Latitudes

• Active 15/25/45
• Minor storm 05/15/25
• Major-severe storm 01/05/15