Viewing archive of Sunday, 18 October 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 Oct 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 291 Issued at 2200Z on 18 OCT 1998IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z SOLAR ACTIVITY BECAME MODERATE WHEN REGION 8358
(N15W69) PRODUCED A M2/1N FLARE AT 18/0145Z. THIS REGION BECAME VERY
ACTIVE DURING A GROWTH PERIOD THAT BEGAN WITH A C9/1F AT 17/1851Z
AND ENDED AT 18/0538Z, PRODUCING ONE M-CLASS AND FIVE C-CLASS
FLARES. ACTIVITY FROM THIS, AND ALL OTHER REGIONS HAVE BEEN VERY LOW
SINCE. NEW REGIONS 8365 (S28E10) AND 8366 (S16E35) WERE NUMBERED
TODAY BRINGING THE TOTAL TO NINE SPOT GROUPS VISIBLE IN WHITE LIGHT.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW.
REGION 8358 WILL LIKELY PRODUCE FURTHER C-CLASS ACTIVITY AND STILL
HAS POTENTIAL FOR AN ISOLATED M-CLASS.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE WITH ISOLATED PERIODS OF MINOR
STORMING IN RESPONSE TO THE CME ON 15 OCT.
III. Event Probabilities 19 OCT to 21 OCT
| Class M | 25% | 15% | 15% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 18 OCT 126 Predicted 19 OCT-21 OCT 130/130/135 90 Day Mean 18 OCT 132
V. Geomagnetic A Indices
OBSERVED AFR/AP 17 OCT 009/009 ESTIMATED AFR/AP 18 OCT 012/015 PREDICTED AFR/AP 19 OCT-21 OCT 025/030-015/020-010/015
VI. Geomagnetic Activity Probabilities 19 OCT to 21 OCT
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 50% | 25% | 10% |
| Minor storm | 30% | 15% | 01% |
| Major-severe storm | 10% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 50% | 30% | 20% |
| Minor storm | 40% | 20% | 10% |
| Major-severe storm | 10% | 05% | 01% |
All times in UTC
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