Joint USAF/NOAA Report of Solar and Geophysical Activity 21 May 2003
SDF Number 141 Issued at 2200Z on 21 May 2003
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was at low levels. Region 362 (S12W03)
produced a C1 flare at 0604Z and continues to exhibit a beta gamma
magnetic configuration. A nine-degree solar filament disappeared
near N19W05 at 20/0005Z. No Earth directed CME was observed in
LASCO imagery.
IB. Solar Activity Forecast: Solar activity is expected to be at
low levels. Regions 362 and 364 have the potential for C-class
flares.
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was at quiet to active levels. Periods of
southward Bz near -10 nT resulted in two active periods during the
day. Solar wind speed began a steady increase, most likely due to
the onset of an equatorial coronal hole high speed flow. Wind speed
increased from 400 km/s to over 600 km/s and continues to rise.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to active levels. The coronal hole high
speed flow is expected to produce active conditions during the
period with a chance of isolated minor storming particularly at the
higher latitudes.
III. Event Probabilities 22 May-24 May
Class M 10/15/15
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 21 May 119
Predicted 22 May-24 May 125/135/140
90 Day Mean 21 May 124
V. Geomagnetic A Indices
Observed Afr/Ap 20 May 009/012
Estimated Afr/Ap 21 May 015/015
Predicted Afr/Ap 22 May-24 May 015/020-015/020-015/020
VI. Geomagnetic Activity Probabilities 22 May-24 May
A. Middle Latitudes
Active 30/35/40
Minor storm 10/15/20
Major-severe storm 01/05/05
B. High Latitudes
Active 40/50/50
Minor storm 20/25/25
Major-severe storm 10/15/15