Viewing archive of Friday, 17 December 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 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 1999IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z SOLAR ACTIVITY WAS LOW. REGION 8798 (S13E21) PRODUCED
SEVERAL C-CLASS X-RAY EVENTS DURING THE PERIOD. THE LASCO SPACECRAFT
OBSERVED A CME CORRESPONDING WITH A C4/1F AT 17/0935Z FROM REGION
8798. THIS REGION REMAINS THE LARGEST REGION ON THE SOLAR DISK WITH
AN AREA OF 550 MILLIONTHS AND CONTAINS A DKC BETA-GAMMA-DELTA SPOT
GROUP. REGION 8803 (S13E10) PRODUCED A LONG DURATION C1/SF AT
17/1750Z. TWO NEW REGIONS WERE NUMBERED TODAY AS REGION 8805
(N18W27) AND REGION 8806 (N18E71).
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW.
REGION 8798 CONTINUES TO HAVE THE POTENTIAL TO PRODUCE AN ISOLATED
M-CLASS EVENT THROUGH THE PERIOD.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED THROUGH THE FORECAST PERIOD.
III. Event Probabilities 18 DEC to 20 DEC
| Class M | 40% | 40% | 40% |
| Class X | 10% | 10% | 10% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 17 DEC 201 Predicted 18 DEC-20 DEC 210/195/190 90 Day Mean 17 DEC 169
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 DEC 006/005 ESTIMATED AFR/AP 17 DEC 008/008 PREDICTED AFR/AP 18 DEC-20 DEC 008/008-008/010-010/012
VI. Geomagnetic Activity Probabilities 18 DEC to 20 DEC
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 10% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 15% | 15% |
| Minor storm | 05% | 10% | 10% |
| Major-severe storm | 01% | 05% | 05% |
All times in UTC
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