Viewing archive of Wednesday, 8 September 1999
Solar activity report
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Report of Solar-Geophysical Activity 1999 Sep 08 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 251 Issued at 2200Z on 08 SEP 1999IA. Analysis of Solar Active Regions and Activity from 07-2100Z to 08-2100Z SOLAR ACTIVITY WAS MODERATE. REGION 8690 (N13E47)
PRODUCED AN M1/1B AT 1217Z. THE REGION PRODUCED ADDITIONAL
SUBFLARES, BUT IS RATHER SMALL (50 MILLIONTHS) AND IS SHOWING ONLY
SLOW GROWTH. REGION 8692 (S27E60) HAS ROTATED INTO VIEW AS AN E-TYPE
REGION AND IS CURRENTLY THE LARGEST GROUP ON THE DISK AT 230
MILLIONTHS. THE GROUP WAS QUIET AND STABLE DURING THE PAST 24 HOURS.
NEW REGION 8694 (S14W14) EMERGED ON THE DISK TODAY. AN ERUPTIVE
PROMINENCE WAS OBSERVED ON THE SOUTHWEST LIMB (S34W90) FROM
1126-1220Z.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW.
THERE IS A SLIGHT CHANCE, HOWEVER, FOR AN ISOLATED M-CLASS EVENT
FROM REGION 8690 OR 8692.
IIA. Geophysical Activity Summary 07-2100Z to 08-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. INITIALLY ACTIVE
CONDITIONS WERE SEEN IN RESPONSE TO A HIGH-SPEED SOLAR WIND STREAM
ASSOCIATED WITH A CORONAL HOLE. CONDITIONS TURNED MARKEDLY QUIET
AFTER 0300Z IN RESPONSE TO A NORTHWARD TURNING OF THE BZ COMPONENT
OF THE INTERPLANETARY MAGNETIC FIELD. UNSETTLED CONDITIONS RETURNED
AFTER 12Z AS BZ TURNED STEADILY SOUTH FOR JUST OVER AN HOUR. QUIET
CONDITIONS PREVAILED FOR THE LAST THREE HOURS OF THE REPORTING
PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT THREE DAYS, BUT THERE
IS A FAIR CHANCE FOR SOME ACTIVE PERIODS, ESPECIALLY AT HIGH
LATITUDES. THE ENHANCED ACTIVITY IS POSSIBLE DUE TO ADDITIONAL
CORONAL HOLES THAT WILL BE ROTATING INTO FAVORABLE POSITIONS.
III. Event Probabilities 09 SEP to 11 SEP
| Class M | 25% | 25% | 25% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 08 SEP 106 Predicted 09 SEP-11 SEP 105/105/100 90 Day Mean 08 SEP 166
V. Geomagnetic A Indices
OBSERVED AFR/AP 07 SEP 012/017 ESTIMATED AFR/AP 08 SEP 010/010 PREDICTED AFR/AP 09 SEP-11 SEP 012/012-012/020-010/015
VI. Geomagnetic Activity Probabilities 09 SEP to 11 SEP
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 20% | 20% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 35% | 25% | 25% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
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