Report of Solar-Geophysical Activity

Report of Solar-Geophysical Activity

Issued: 2008 Apr 24 2200 UTC

Prepared jointly by the U.S. Dept. of Commerce, NOAA,

Space Weather Prediction Center and the U.S. Air Force.

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 115 Issued at 2200Z on 24 Apr 2008

IA. Analysis of Solar Active Regions and Activity from 23/2100Z

to 24/2100Z: Solar activity was very low.

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

low.

IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z:

The geomagnetic field was at unsettled to active conditions due to

the continued influence of the recurrent coronal hole high speed

stream. Solar wind speeds, as measured from the ACE spacecraft,

remain around 600 km/s. The greater than 2 MeV electron flux at

geosynchronous orbit was at high levels.

IIB. Geophysical Activity Forecast: The geomagnetic field is

expected to be unsettled with isolated active periods for 25 April.

Predominantly quiet conditions are expected for 26-27 April.

III. Event Probabilities 25 Apr-27 Apr

Class M 01/01/01

Class X 01/01/01

Proton 01/01/01

PCAF Green

IV. Penticton 10.7 cm Flux

Observed 24 Apr 070

Predicted 25 Apr-27 Apr 070/070/070

90 Day Mean 24 Apr 072

V. Geomagnetic A Indices

Observed Afr/Ap 23 Apr 017/032

Estimated Afr/Ap 24 Apr 015/022

Predicted Afr/Ap 25 Apr-27 Apr 010/012-005/008-005/005

VI. Geomagnetic Activity Probabilities 25 Apr-27 Apr

A. Middle Latitudes

Active 25/10/10

Minor storm 05/05/05

Major-severe storm 01/01/01

B. High Latitudes

Active 30/10/10

Minor storm 10/05/05

Major-severe storm 01/01/01