Viewing archive of Friday, 18 December 1998
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 1998 Dec 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 352 Issued at 2200Z on 18 DEC 1998IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z SOLAR ACTIVITY WAS HIGH. REGION 8415 (N19E61) PRODUCED
A M8/2N EVENT AT 18/1722Z WITH AN ASSOCIATED TYPE II SWEEP. THE
TYPE II SPEED WAS ESTIMATED AT 1200 KM/S. AN 880 SFU TENFLARE WAS
ALSO DETECTED DURING THE M8 X-RAY EVENT. REGION 8415 ALSO PRODUCED
NUMEROUS C-CLASS X-RAY EVENTS DURING THE PERIOD.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE WITH CONTINUED C-CLASS EVENTS AND THE LIKELIHOOD OF MORE
M-CLASS X-RAY EVENTS FROM REGION 8415 OR REGION 8409 (S27W63).
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
THE GEOMAGNETIC FIELD WAS QUIET. A CME WAS OBSERVED FROM SOHO LASCO
IMAGERY AT 18/1834Z IN ASSOCIATION WITH THE M8 X-RAY EVENT IN REGION
8415 EARLIER TODAY. LASCO AND EIT REPORTED A PARTIAL HALO.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET, BECOMING QUIET TO UNSETTLED DURING THE THREE
DAY PERIOD. NO SIGNIFICANT GEOMAGNETIC EFFECTS ARE EXPECTED FROM
THE X-RAY EVENT AT 18/1722Z UNTIL THE END OF THE PERIOD.
III. Event Probabilities 19 DEC to 21 DEC
| Class M | 50% | 50% | 50% |
| Class X | 05% | 05% | 05% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 18 DEC 155 Predicted 19 DEC-21 DEC 150/145/140 90 Day Mean 18 DEC 133
V. Geomagnetic A Indices
OBSERVED AFR/AP 17 DEC 000/002 ESTIMATED AFR/AP 18 DEC 002/003 PREDICTED AFR/AP 19 DEC-21 DEC 005/009-008/009-008/009
VI. Geomagnetic Activity Probabilities 19 DEC to 21 DEC
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 01% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 20% | 20% |
| Minor storm | 01% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
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