Viewing archive of Saturday, 21 August 1999
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 1999 Aug 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 233 Issued at 2200Z on 21 AUG 1999IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS HIGH. REGION 8674 (S24E66) PRODUCED
AN M9.8/1N EVENT WITH AN ACCOMPANYING TYPE II SWEEP (700 KM/S) AT
20/2310, AND A 480 SFU 10 CM BURST. REGION 8674 ALSO PRODUCED AN
M3/1B EVENT WITH AN ACCOMPANYING WEAK TYPE II (500 KM/S), AND A 290
SFU 10CM BURST AT 21/1634UT. THE ONLY OTHER REGION OF NOTE WAS
REGION 8668 (N22W11) WHICH PRODUCED A 7 DEGREE DISAPPEARING SOLAR
FILAMENT WITH AN OPTICAL SUBFLARE AT 21/1416UT.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE WITH AN ISOLATED CHANCE OF AN X-CLASS EVENT FROM REGION
8674.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. THE GREATER THAN 2 MEV
ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT WAS AT HIGH LEVELS FOR THE
ENTIRE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED.
III. Event Probabilities 22 AUG to 24 AUG
| Class M | 60% | 60% | 60% |
| Class X | 10% | 10% | 10% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 AUG 161 Predicted 22 AUG-24 AUG 165/170/175 90 Day Mean 21 AUG 163
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 AUG 022/033 ESTIMATED AFR/AP 21 AUG 010/010 PREDICTED AFR/AP 22 AUG-24 AUG 010/008-010/008-010/008
VI. Geomagnetic Activity Probabilities 22 AUG to 24 AUG
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 20% | 20% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
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