Joint USAF/NOAA Report of Solar and Geophysical Activity 16 May 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 May 16 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 136 Issued at 2200Z on 16 May 2007

IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity remained at low levels. Region 956 (N02E35) produced a C2/Sf flare at 16/1741Z along with multiple B-class flares during the past 24 hours. This region continues to show rapid growth in sunspot area and is now magnetically classified a Dkc beta-gamma-delta sunspot group. Region 955 (S07W77) continues to decay and is currently an Axx alpha sunspot group. New Region 957 (S04W34) was numbered today and is depicting several umbra.

IB. Solar Activity Forecast: Solar activity is expected to be at low to moderate levels. Isolated M-class flares are possible due to the magnetic complexities of Region 956.

IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic field was at predominantly quiet levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at predominantly quiet levels on 17 and 18 May. A recurrent coronal hole high speed stream is expected to become geoeffective on 19 May. Unsettled to active conditions are expected with isolated minor storm periods possible, as the coronal hole becomes favorably positioned.

III. Event Probabilities 17 May-19 May

• Class M 35/35/40
• Class X 10/10/15
• Proton 01/01/05
• PCAF Green

IV. Penticton 10.7 cm Flux

• Observed 16 May 077
• Predicted 17 May-19 May 080/075/075
• 90 Day Mean 16 May 074

V. Geomagnetic A Indices

• Observed Afr/Ap 15 May 004/006
• Estimated Afr/Ap 16 May 005/005
• Predicted Afr/Ap 17 May-19 May 005/005-005/005-010/010

VI. Geomagnetic Activity Probabilities 17 May-19 May

A. Middle Latitudes

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

B. High Latitudes

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