Joint USAF/NOAA Report of Solar and Geophysical Activity 19 May 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 May 20 0011 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 139 Issued at 2200Z on 19 May 2007

IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity was very low. Region 956 (N02W06) produced several B-class flares during the past 24 hours, the largest of which was a B9 flare at 19/1302Z. A disappearing solar filament was observed from this region starting at 19/1231Z.

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

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field has been quiet to unsettled. The solar wind speed remains elevated at approximately 600 km/s due to the coronal hole high speed stream.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled with possible active periods during local nighttime hours on 20 May. Expect mostly quiet conditions on 21 – 22 May.

III. Event Probabilities 20 May-22 May

• Class M 10/10/10
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 19 May 075
• Predicted 20 May-22 May 075/075/075
• 90 Day Mean 19 May 074

V. Geomagnetic A Indices

• Observed Afr/Ap 18 May 015/018
• Estimated Afr/Ap 19 May 010/015
• Predicted Afr/Ap 20 May-22 May 008/010-005/005-005/005

VI. Geomagnetic Activity Probabilities 20 May-22 May

A. Middle Latitudes

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

B. High Latitudes

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