Viewing archive of Monday, 21 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 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 355 Issued at 2200Z on 21 DEC 1998IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS LOW. THE LARGEST EVENT OF THE PERIOD
WAS AN OPTICALLY UNCORRELATED C5 FLARE AT 21/0429Z. REGION 8416
(N19E59) PRODUCED A C2/SF AT 21/1334Z. THIS REGION IS A SMALL E
CLASS GROUP, POSSIBLY WITH MIXED POLARITIES. REGION 8415 (N20E24)
EXHIBITED CONTINUED SLOW DECAY BUT RETAINED ITS BETA GAMMA MAGNETIC
CLASSIFICATION. THIS REGION PRODUCED A C1/SF AT 21/1941Z. THE LARGE
FILAMENT IN SPOTLESS PLAGE REGION 8414 (N26W10) WAS GENERALLY QUIET
BUT SHOWED SLOW DENSIFICATION DURING THE PERIOD.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD REMAIN AT
PREDOMINANTLY LOW LEVELS. REGION 8415 RETAINS THE CAPABILITY OF
PRODUCING AN ISOLATED M-CLASS EVENT, BUT THAT POSSIBILITY IS WANING
WITH THE DECAY IN THE REGION. REGION 8414 MAY PRODUCE A LONG
DURATION X-RAY EVENT SHOULD THE LARGE FILAMENT ERUPT. SHOULD THIS
OCCUR, A LARGE CORONAL MASS EJECTION WOULD LIKELY RESULT.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET. AT THIS TIME, THE EXPECTED SHOCK
FROM THE HALO CORONAL MASS EJECTION ON 18 DEC HAS NOT ARRIVED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD
BECOME DISTURBED ON 22 DEC. GENERALLY UNSETTLED TO ACTIVE CONDITIONS
ARE EXPECTED ON THAT DAY. PERIODS OF MINOR AND POSSIBLY MAJOR
STORMING ARE POSSIBLE SHOULD THAT DISTURBANCE ARRIVE AS EXPECTED.
QUIET TO UNSETTLED GEOMAGNETIC CONDITIONS ARE FORECAST FOR 23-24
DEC.
III. Event Probabilities 22 DEC to 24 DEC
| Class M | 40% | 35% | 30% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 DEC 135 Predicted 22 DEC-24 DEC 132/135/138 90 Day Mean 21 DEC 133
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 DEC 009/011 ESTIMATED AFR/AP 21 DEC 005/010 PREDICTED AFR/AP 22 DEC-24 DEC 025/018-012/009-008/009
VI. Geomagnetic Activity Probabilities 22 DEC to 24 DEC
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 20% | 10% |
| Minor storm | 20% | 10% | 05% |
| Major-severe storm | 20% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 20% | 15% |
| Minor storm | 25% | 10% | 05% |
| Major-severe storm | 30% | 05% | 01% |
All times in UTC
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