Report of Solar-Geophysical Activity

Issued: 2006 Apr 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 108 Issued at 2200Z on 18 Apr 2006 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity remained at very low levels. A small filament eruption occurred early in the period and a related CME was observed on LASCO imagery shortly there after. The CME does not appear to be Earth directed. Region 874 (N00E15) was numbered today.

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

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:

The geomagnetic field was at quiet to unsettled levels. The greater than 2 MeV electron flux at geosynchronous orbit reached very high levels again today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels.

III. Event Probabilities 19 Apr-21 Apr

Class M 01/01/01

Class X 01/01/01

Proton 01/01/01

PCAF green

IV. Penticton 10.7 cm Flux

Observed 18 Apr 074

Predicted 19 Apr-21 Apr 075/075/075

90 Day Mean 18 Apr 078

V. Geomagnetic A Indices

Observed Afr/Ap 17 Apr 004/006

Estimated Afr/Ap 18 Apr 005/008

Predicted Afr/Ap 19 Apr-21 Apr 005/008-005/008-005/008 VI. Geomagnetic Activity Probabilities 19 Apr-21 Apr A. Middle Latitudes

Active 15/15/15

Minor storm 01/01/01

Major-severe storm 01/01/01

B. High Latitudes

Active 20/20/20

Minor storm 05/05/05

Major-severe storm 01/01/01