Viewing archive of Wednesday, 21 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 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 294 Issued at 2200Z on 21 OCT 1998IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS LOW. THE LARGEST X-RAY FLARE OF THE
PAST DAY WAS A LONG DURATION C7 THAT, FROM EIT IMAGES, APPARENTLY
OCCURRED FROM BEHIND THE SOUTHWEST LIMB. THIS FLARE WAS ASSOCIATED
WITH A WEAK TYPE II/IV RADIO SWEEP AND CORONAL LOOPS. REGION 8365
(S28W24) HAS BEEN EMERGING RAPIDLY, MORE THAN DOUBLING ITS SUNSPOT
AREA. THIS REGION HAS STARTED TO GENERATE SMALL FLARES; THE LARGEST
SO FAR BEING A C1/SF AT 21/1132Z. NEW REGION 8367 (N16E00) EMERGED
JUST TO THE SOUTHEAST OF REGION 8362 (N18W08).
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW.
C-CLASS ACTIVITY IS POSSIBLE FROM REGION 8361 (N15W94), AS IT ROUNDS
THE WEST LIMB, AND REGION 8365.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS UNSETTLED TO ACTIVE. THIS ACTIVITY IS
BELIEVED TO BE THE RESULT OF ALFVENIC WAVE ACTIVITY ASSOCIATED WITH
A HIGH-SPEED STREAM FROM THE NORTHERN POLAR CORONAL HOLE. THE 2 MEV
ELECTRON FLUX WAS MODERATE TO HIGH.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED TO ACTIVE FOR THE NEXT 24 HOURS, BECOMING
QUIET TO UNSETTLED.
III. Event Probabilities 22 OCT to 24 OCT
| Class M | 10% | 05% | 01% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 OCT 118 Predicted 22 OCT-24 OCT 115/115/115 90 Day Mean 21 OCT 132
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 OCT 011/017 ESTIMATED AFR/AP 21 OCT 022/020 PREDICTED AFR/AP 22 OCT-24 OCT 018/020-015/012-010/010
VI. Geomagnetic Activity Probabilities 22 OCT to 24 OCT
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 10% | 10% | 05% |
| Major-severe storm | 05% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 10% | 10% | 05% |
| Major-severe storm | 05% | 01% | 01% |
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