Joint USAF/NOAA Report of Solar and Geophysical Activity 18 Sep 2006

Product: Report of Solar-Geophysical Activity
Issued: 2006 Sep 18 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 261 Issued at 2200Z on 18 Sep 2006

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity was low. Newly numbered Region 910 (S08E49) produced a C1 flare at 18/1945Z.

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

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to minor storm levels. Two minor storm periods from 18/0000Z – 18/0600Z were likely the result of elevated solar wind speed from the coronal hole high speed stream. Solar wind speed remains elevated at time of issue at approximately 650 km/s. The greater than 2 MeV electron flux reached high levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled with a chance for active periods on 19 September as the coronal hole rotates out of a geoeffective position. Expect mostly quiet conditions on 20 – 21 September.

III. Event Probabilities 19 Sep-21 Sep

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

IV. Penticton 10.7 cm Flux

• Observed 18 Sep 074
• Predicted 19 Sep-21 Sep 075/075/075
• 90 Day Mean 18 Sep 077

V. Geomagnetic A Indices

• Observed Afr/Ap 17 Sep 009/016
• Estimated Afr/Ap 18 Sep 018/020
• Predicted Afr/Ap 19 Sep-21 Sep 010/012-005/008-005/005

VI. Geomagnetic Activity Probabilities 19 Sep-21 Sep A. Middle Latitudes

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

B. High Latitudes

• Active 25/20/15
• Minor storm 10/05/05
• Major-severe storm 01/01/01