Viewing archive of Friday, 27 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 27 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 239 Issued at 2200Z on 27 AUG 1999IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z SOLAR ACTIVITY WAS HIGH. REGION 8674 (S24W16) PRODUCED
AN M5/2N FLARE AT 1307Z. THIS REGION ALSO HAD AN M3/2N AT 1635Z, AND
WAS THE LIKELY SITE OF THE M3 EVENT EARLIER AT 0137Z. THE CENTER OF
THE DISK IS DOMINATED BY THE MERGING OF REGIONS 8674 AND 8673
(S19W24), AND THE TWO ARE NOW NEARLY INDISTINGUISHABLE. ALTHOUGH THE
X-RAY OUTPUT OF TODAY'S EVENTS WAS SUBSTANTIAL, THE RADIO EMISSION
WAS SMALL, AND NO SWEEP FREQUENCY EVENTS WERE DETECTED. ONE NEW
REGION WAS NUMBERED, REGION 8680 (N22W87).
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE TO HIGH. REGIONS 8673 AND 8674 ARE LARGE, MAGNETICALLY
COMPLEX, AND DYNAMIC. WATCH FOR ADDITIONAL M-CLASS, AND ISOLATED
X-CLASS, ACTIVITY DURING THE NEXT THREE DAYS.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO MILDLY ACTIVE. SOLAR WIND SPEEDS
IN EXCESS OF 600 KM/S ARE STILL OCCURRING, LIKELY ORIGINATING FROM A
WELL- POSITIONED CORONAL HOLE WEST OF CENTRAL MERIDIAN. THE GREATER
THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT APPROACHED HIGH
LEVELS AT APPROXIMATELY 1500Z.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED THE NEXT THREE DAYS. THERE IS A GOOD CHANCE
FOR ISOLATED ACTIVE CONDITIONS DURING LOCAL NIGHTTIME HOURS. A
GREATER THAN 10 MEV PROTON EVENT IS ALSO POSSIBLE DURING THE PERIOD,
PENDING FURTHER ACTIVITY FROM REGIONS 8673 AND 8674.
III. Event Probabilities 28 AUG to 30 AUG
| Class M | 80% | 80% | 80% |
| Class X | 40% | 40% | 40% |
| Proton | 40% | 40% | 40% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 27 AUG 223 Predicted 28 AUG-30 AUG 225/220/220 90 Day Mean 27 AUG 167
V. Geomagnetic A Indices
OBSERVED AFR/AP 26 AUG 010/013 ESTIMATED AFR/AP 27 AUG 010/012 PREDICTED AFR/AP 28 AUG-30 AUG 010/010-010/010-010/010
VI. Geomagnetic Activity Probabilities 28 AUG to 30 AUG
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 20% |
| Minor storm | 10% | 10% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 30% |
| Minor storm | 15% | 15% | 10% |
| Major-severe storm | 01% | 01% | 01% |
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