Viewing archive of Friday, 27 August 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 Aug 27 2200 UTC
Prepared 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 1999

IA. 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 FROM 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 M80%80%80%
Class X40%40%40%
Proton40%40%40%
PCAFGREEN
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
Active30%30%20%
Minor storm10%10%05%
Major-severe storm01%01%01%
B. High Latitudes
Active40%40%30%
Minor storm15%15%10%
Major-severe storm01%01%01%

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