Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 21 Dec 2003

By SpaceRef Editor

December 21, 2003

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 2003 Dec 21 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 355 Issued at 2200Z on 21 Dec 2003

IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was low. Occasional low C-class flares
were observed in Regions 525 (N09E05) and 528 (N09E37). Both regions
continue in a slow growth phase with some weak mixed polarities
noted. New Region 530 (S20E64) was numbered today.

IB. Solar Activity Forecast: Solar activity is expected to continue
at low levels. There is a small chance for an M-class flare from
Regions 525 and 528.

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was unsettled to active. This disturbance is
due to elevated solar wind from an elongated transequatorial coronal
hole which rotated into a geoeffective position on 20 December.
Solar wind speed now exceeds 600 km/s, but predominantly northward
IMF Bz is thwarting a more significant response in the geomagnetic
field.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to continue at unsettled to active levels through 22
December. The coronal hole high speed solar wind flow in progress
now is expected to subside by 23 December. Quiet to unsettled
condition are likely on 23-24 December.

III. Event Probabilities 22 Dec-24 Dec