Viewing archive of Thursday, 17 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 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 351 Issued at 2200Z on 17 DEC 1998IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z SOLAR ACTIVITY WAS MODERATE WITH SEVERAL C-CLASS X-RAY
EVENTS AND ONE ISOLATED M-CLASS X-RAY FLARE DURING THE PERIOD.
REGION 8409 (S28W52) PRODUCED A M3/1N EVENT AT 17/0745Z WITH AN
ASSOCIATED TYPE II SWEEP. THE TYPE II SPEED WAS ESTIMATED AT 500
KM/S. A 230 SFU TENFLARE WAS ALSO DETECTED DURING THE M3 EVENT. AT
17/1418Z, REGION 8409 PRODUCED A C7/SN EVENT. AN ASSOCIATED TYPE II
SWEEP WITH AN ESTIMATED SPEED OF 600 KM/S WAS OBSERVED. REGION 8415
(N19E70) WAS NUMBERED AND IS CURRENTLY A BXO BETA SPOT GROUP WITH
SEVEN SPOTS. AT 17/1753Z, REGION 8415 PRODUCED A C6/1F EVENT.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
WITH CONTINUED C-CLASS EVENTS. THERE IS A CHANCE FOR AN ISOLATED
M-CLASS X-RAY EVENT OUT OF REGION 8409.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
THE GEOMAGNETIC FIELD WAS QUIET. NO FURTHER AFFECTS WERE OBSERVED
FROM THE CORONAL HOLE IN THE NORTHERN HEMISPHERE DURING THE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET DURING THE FIRST DAY OF THE PERIOD BECOMING
QUIET TO UNSETTLED DURING THE LAST TWO DAYS OF THE PERIOD.
III. Event Probabilities 18 DEC to 20 DEC
| Class M | 25% | 25% | 25% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 17 DEC 146 Predicted 18 DEC-20 DEC 145/140/135 90 Day Mean 17 DEC 133
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 DEC 009/011 ESTIMATED AFR/AP 17 DEC 001/002 PREDICTED AFR/AP 18 DEC-20 DEC 005/009-008/009-008/009
VI. Geomagnetic Activity Probabilities 18 DEC to 20 DEC
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 10% |
| Minor storm | 01% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 01% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
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