Viewing archive of Sunday, 21 February 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 Feb 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 052 Issued at 2200Z on 21 FEB 1999IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS MODERATE. THIS WAS DUE TO A SINGLE
M-CLASS EVENT. A LONG DURATION (1 HOUR) M1/SF AT 21/1345UT FROM
REGION 8462 (N20W79). THE ONLY OTHER EVENT OF NOTICE WAS AN
OPTICALLY UNCORRELATED C8 X-RAY FLARE AT 21/0950UT. REGION 8462 WAS
THE MOST ACTIVE REGION. RGN 8464 (N18W53) PRODUCED A SINGLE
SUBFLARE. ALL THE REST OF THE REGIONS WERE QUIET AND STABLE. NEW
REGION 8469 (N15W18) EMERGED AS A 4 SPOT CSO BETA GROUP.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW.
THERE IS SLIGHT CHANCE OF REGION 8462 PRODUCING ANOTHER ISOLATED
M-CLASS EVENT.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET. THE GREATER THAN 2 MEV ELECTRON FLUX
AT GEOSYNCHRONOUS ORBIT REACHED THRESHOLD LEVELS AT 21/1700 AND
REMAINED AT THAT LEVEL FOR THE REST OF THE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO VARY FROM QUIET TO ACTIVE LEVELS FOR THE NEXT 2 DAYS. A
HIGH SPEED STREAM FROM A WELL POSITIONED CORONAL HOLE MAY AFFECT THE
NEAR EARTH ENVIRONS IN THE NEXT 24-48 HOURS. CONDITIONS SHOULD
RETURN TO QUIET TO UNSETTLED ON THE 3RD DAY.
III. Event Probabilities 22 FEB to 24 FEB
| Class M | 30% | 25% | 20% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 FEB 147 Predicted 22 FEB-24 FEB 145/140/135 90 Day Mean 21 FEB 147
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 FEB 002/005 ESTIMATED AFR/AP 21 FEB 005/010 PREDICTED AFR/AP 22 FEB-24 FEB 005/012-015/017-010/008
VI. Geomagnetic Activity Probabilities 22 FEB to 24 FEB
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 30% | 20% |
| Minor storm | 05% | 10% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 40% | 30% |
| Minor storm | 05% | 15% | 10% |
| Major-severe storm | 01% | 01% | 01% |
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