Viewing archive of Thursday, 19 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 19 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 231 Issued at 2200Z on 19 AUG 1999IA. Analysis of Solar Active Regions and Activity from 18-2100Z to 19-2100Z SOLAR ACTIVITY WAS MODERATE. REGION 8672 (N15W17)
PRODUCED AN M1/1N AT 1205Z, BUT LITTLE ELSE. REGION 8668 (N22E01)
STILL DOMINATES THE DISK, BUT WAS STABLE. NEWLY ASSIGNED REGION 8673
(S17E81) ROTATED INTO VIEW. THIS IS THE APPARENT RETURN OF OLD
REGION 8647, THE SITE OF M AND X CLASS ACTIVITY LAST ROTATION.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. MORE ISOLATED M-CLASS EVENTS MAY OCCUR FROM REGIONS
8668 AND 8673.
IIA. Geophysical Activity Summary 18-2100Z to 19-2100Z
THE GEOMAGNETIC FIELD WAS AT UNSETTLED TO MINOR STORM LEVELS DURING
THE DAY. THE SOLAR WIND IS STILL GUSTING TO SPEEDS NEAR 800 KM/S,
DRIVING THIS ELEVATED MAGNETIC ACTIVITY. THE GREATER THAN 2 MEV
ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT PERSISTED AT HIGH LEVELS
THROUGHOUT THE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE THE NEXT 24 HOURS. THE CURRENT
DISTURBANCE SHOULD SLOWLY WEAKEN AND YIELD TO UNSETTLED CONDITIONS
BY THE END OF THE INTERVAL.
III. Event Probabilities 20 AUG to 22 AUG
| Class M | 25% | 25% | 25% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 19 AUG 135 Predicted 20 AUG-22 AUG 140/145/150 90 Day Mean 19 AUG 163
V. Geomagnetic A Indices
OBSERVED AFR/AP 18 AUG 028/026 ESTIMATED AFR/AP 19 AUG 020/020 PREDICTED AFR/AP 20 AUG-22 AUG 015/020-015/015-010/010
VI. Geomagnetic Activity Probabilities 20 AUG to 22 AUG
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 30% | 20% |
| Minor storm | 15% | 10% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 50% | 40% | 30% |
| Minor storm | 20% | 15% | 10% |
| Major-severe storm | 05% | 01% | 01% |
All times in UTC
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