Viewing archive of Monday, 21 September 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 Sep 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 264 Issued at 2200Z on 21 SEP 1998IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS LOW. THE LARGEST AND MOST ACTIVE
REGION CURRENTLY VISIBLE, REGION 8340 (N19E25), PRODUCED A C2/SF AT
21/0806UT AND A C2/1F AT 21/1842UT. THIS REGION IS STILL UNDERGOING
SLOW GROWTH AND IS CURRENTLY A DKO GROUP COVERING 540 MILLIONTHS OF
WHITE LIGHT AREA. REMAINING REGIONS WERE QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO REMAIN
LOW. CONTINUED C-CLASS ACTIVITY IS EXPECTED FROM REGION 8340 WITH A
SLIGHT CHANCE FOR AN M-CLASS.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED WITH ISOLATED ACTIVE
PERIODS IN HIGH LATITUDES.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO REMAIN QUIET TO UNSETTLED WITH OCCASIONAL ACTIVE PERIODS
AT HIGH LATITUDES.
III. Event Probabilities 22 SEP to 24 SEP
| Class M | 25% | 25% | 25% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 SEP 138 Predicted 22 SEP-24 SEP 140/145/150 90 Day Mean 21 SEP 128
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 SEP 004/008 ESTIMATED AFR/AP 21 SEP 012/015 PREDICTED AFR/AP 22 SEP-24 SEP 015/015-015/015-015/020
VI. Geomagnetic Activity Probabilities 22 SEP to 24 SEP
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 20% |
| Minor storm | 10% | 10% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 30% |
| Minor storm | 15% | 15% | 10% |
| Major-severe storm | 01% | 01% | 01% |
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