Issued: 2007 Apr 19 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 109 Issued at 2200Z on 19 Apr 2007 IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity was very low. No flares were observed during the past 24 hours, and the visible disk was spotless.

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

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z:

The geomagnetic field was quiet to unsettled.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to range from quiet to active for the next three days

(20-22 April). Isolated minor storm conditions are possible at high latitudes on 20 April due to a favorably positioned coronal hole.

III. Event Probabilities 20 Apr-22 Apr

Class M 01/01/01

Class X 01/01/01

Proton 01/01/01

PCAF Green

IV. Penticton 10.7 cm Flux

Observed 19 Apr 068

Predicted 20 Apr-22 Apr 070/070/070

90 Day Mean 19 Apr 075

V. Geomagnetic A Indices

Observed Afr/Ap 18 Apr 006/009

Estimated Afr/Ap 19 Apr 008/010

Predicted Afr/Ap 20 Apr-22 Apr 015/015-008/010-008/008 VI. Geomagnetic Activity Probabilities 20 Apr-22 Apr A. Middle Latitudes

Active 30/25/20

Minor storm 20/10/05

Major-severe storm 05/01/01

B. High Latitudes

Active 35/30/25

Minor storm 25/15/10

Major-severe storm 10/05/01

http://www.sec.noaa.gov/SWN/

http://www.sec.noaa.gov/alerts/

NOAA Space Weather Scale descriptions can be found at www.sec.noaa.gov/NOAAscales