Viewing archive of Thursday, 11 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 11 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 042 Issued at 2200Z on 11 FEB 1999IA. Analysis of Solar Active Regions and Activity from 10-2100Z to 11-2100Z SOLAR ACTIVITY WAS LOW. THE LARGEST EVENT THIS PERIOD
WAS A LONG DURATION C3.7 X-RAY EVENT AT 10/2346Z. SPACE BASED
IMAGERY SUGGEST REGION 8457 (N16E36) AS THE LIKELY SOURCE OF THIS
EVENT. REGION 8356 (N23E16) ALSO PRODUCED MINOR C-CLASS SUBFLARES AS
IT CONTINUES TO DEVELOP AND NOW EXHIBITS A MODERATELY COMPLEX
BETA-GAMMA CONFIGURATION. THE MOST IMPRESSIVE GROWTH OCCURRED IN
REGION 8458 (S22E42) WHERE A WEAK DELTA CONFIGURATION DEVELOPED LATE
IN THE PERIOD. OTHER DYNAMIC DEVELOPMENTS IN THIS REGION INDICATE
INCREASED FLARE POTENTIAL AS THE REGION NOW MEASURES 700 MILLIONTHS
OF WHITE LIGHT AREA. REMAINING REGIONS HAVE BEEN QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. EXPECT CONTINUED C-CLASS X-RAY ACTIVITY FROM REGIONS
8456 AND 8457 WITH A SLIGHT CHANCE FOR AN M-CLASS. REGION 8458 IS
QUICKLY DEVELOPING AS A LIKELY SOURCE FOR M-CLASS ACTIVITY.
IIA. Geophysical Activity Summary 10-2100Z to 11-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED UNTIL A WEAK
INTERPLANETARY SHOCK WAS OBSERVED AT 11/0900Z; UNSETTLED TO ACTIVE
CONDITIONS HAVE PREVAILED SINCE.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO REMAIN UNSETTLED TO ACTIVE THROUGH THE FIRST HALF OF
NEXT PERIOD, BECOMING QUIET TO UNSETTLED THEREAFTER.
III. Event Probabilities 12 FEB to 14 FEB
| Class M | 35% | 35% | 35% |
| Class X | 10% | 10% | 10% |
| Proton | 05% | 05% | 10% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 11 FEB 164 Predicted 12 FEB-14 FEB 170/175/175 90 Day Mean 11 FEB 141
V. Geomagnetic A Indices
OBSERVED AFR/AP 10 FEB 003/006 ESTIMATED AFR/AP 11 FEB 017/010 PREDICTED AFR/AP 12 FEB-14 FEB 012/012-008/012-008/012
VI. Geomagnetic Activity Probabilities 12 FEB to 14 FEB
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 70% | 15% | 15% |
| Minor storm | 20% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 80% | 20% | 20% |
| Minor storm | 40% | 05% | 05% |
| Major-severe storm | 10% | 01% | 01% |
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