Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 20 Jan 2004

By SpaceRef Editor

January 20, 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 Jan 20 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 020 Issued at 2200Z on 20 Jan 2004

IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity was high. Region 540 (S14W22) produced
an M6/2n flare at 20/0743Z. Radio bursts associated with this flare
included a 4500 sfu burst on 245 MHz and Type II sweep with a shock
speed of 950 km/s. A CME was visible on LASCO imagery. Region 540
also produced an impressive long duration C5 flare that occurred
between 19/2202Z through 20/0229Z, peaking at 20/0045Z. A full halo
CME was observed with this event. Soon after the eruption in Region
540, segments of the large circular filament in the northwest
quadrant also erupted. Region 540 maintains a weak delta
configuration in its trailing spots, but further decay in total area
was also noted. The trailing spots in Region 542 (N10W03) have been
identified as a separate region and were numbered as Region 544.

IB. Solar Activity Forecast: Solar activity is expected to be low
to moderate. Though in decay, Region 540 still maintains potential
for isolated M-class flares. The remaining three spot groups on the
visible disk have potential for C-class activity.

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was quiet to active. Solar wind speed is in
gradual decline as a large transequatorial coronal hole rotates out
of a geoeffective position. Solar wind speed decreased to near 500
km/s, but periods of southward Bz generated occasional active
periods. The greater than 2 MeV electron flux at geosynchronous
orbit reached high levels again today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to range from quiet to major storming over the next three
days. Quiet to active periods are expected on 21 January. The full
halo CME observed on LASCO imagery at 20/0006Z will likely impact
the geomagnetic field early on 22 January. Active to major storm
periods are possible. Unsettled to active conditions are expected on
January 23 as the storm subsides.

III. Event Probabilities 21 Jan-23 Jan