Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 18 Sep 2004

By SpaceRef Editor

September 18, 2004

Filed under Space Weather Prediction Center (NOAA), Space Weather Solar-Geophysical Activity, US

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.

Updated 2004 Sep 18 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 262 Issued at 2200Z on 18 Sep 2004

IA. Analysis of Solar Active Regions and Activity from 17/2100Z
to 18/2100Z: Solar activity was low. Region 673 (S13E35) produced
the only C-class activity of the period, a single C1 flare at
18/1609Z. Occasional B-class flares were also observed from this
region and from Region 672 (N06W45). Region 673 is a moderate size
beta group that exhibited little change this period. Region 672 has
decayed considerably over the past 48 hours. No other significant
activity or changes were noted.

IB. Solar Activity Forecast: Solar activity is expected to be low
to very low. Isolated C-class activity is possible from Regions 672
and 673.

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field ranged from quiet to minor storm levels with a
period of major storming between 18/0000 – 0300Z. The storm levels
were in response to a prolonged period of southward IMF Bz and solar
wind speeds near 500 km/s. The geomagnetic field was predominantly
quiet to end the period as the solar wind speed declined to 420 km/s
and IMF Bz was sustained north. 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 quiet to unsettled with isolated active periods at
high latitudes.

III. Event Probabilities 19 Sep-21 Sep