Joint USAF/NOAA Report of Solar and Geophysical Activity 21 Aug 2003
SDF Number 233 Issued at 2200Z on 21 Aug 2003
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was low. A number of small x-ray flares
occurred in Region 431 (S10W90) from its location just beyond the
west limb. The largest was a C4 at 21/1522 UTC. The largest region
presently on the disk is 436 (N07E17) but it appears relatively
simple and has not flared today. New Regions 438 (S31W31), 439
(N08W23), 440 (S08E12), and 441 (N12E48) emerged on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low.
C-class flares are possible in Regions 431, 436, and an area not
yet numbered rotating around the east limb near S12E90.
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field ranged from unsettled to severe storm levels.
The most disturbed period was from 21/0600 to 0900 UTC. ACE solar
wind data indicates the gradual onset of a coronal hole
high-speed-stream over the past 24 hours. Current solar wind
parameters include speed at about 700 km/s, density from 1 to 5
p/cc, and Bz fluctuating between +/- 10 nT.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at mostly active to minor storm levels for the
duration of the forecast period as the high-speed-stream disturbance
continues.
III. Event Probabilities 22 Aug-24 Aug
- Class M 10/10/10
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 21 Aug 119
- Predicted 22 Aug-24 Aug 115/110/110
- 90 Day Mean 21 Aug 127
V. Geomagnetic A Indices
- Observed Afr/Ap 20 Aug 012/015
- Estimated Afr/Ap 21 Aug 040/052
- Predicted Afr/Ap 22 Aug-24 Aug 025/030-025/030-020/025
VI. Geomagnetic Activity Probabilities 22 Aug-24 Aug
A. Middle Latitudes
- Active 60/60/60
- Minor storm 20/20/20
- Major-severe storm 05/05/05
B. High Latitudes
- Active 65/65/65
- Minor storm 30/30/30
- Major-severe storm 05/05/05
