Viewing archive of Tuesday, 21 July 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 Jul 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 202 Issued at 2200Z on 21 JUL 1998IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS VERY LOW. THREE NEW REGIONS WERE
NUMBERED TODAY: REGION 8279, (EMERGED ON DISK AT N26E33), REGION
8280 (ROTATING INTO VIEW AT S22E76), AND 8281 (A SIMPLE A-TYPE GROUP
AT N16E73). REGION 8280 APPEARS TO HAVE MATURE PENUMBRA ON LEADER
AND TRAILER PORTIONS OF THE GROUP. REGION 8277 (S12W41) GREW
STEADILY AND EXHIBITED BRIGHT H-ALPHA PLAGE, BUT COULD ONLY MUSTER
ONE SUBFLARE OVER THE PAST 24 HOURS.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE
PREDOMINANTLY LOW. THERE IS A CHANCE, HOWEVER, FOR AN ISOLATED
M-CLASS FLARE OVER THE NEXT THREE DAYS. REGIONS 8277 AND 8280 ARE
CONSIDERED TO BE THE MOST LIKELY SOURCE REGIONS FOR ENHANCED
ACTIVITY.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED AT MID-LATITUDES AND
RANGED FROM QUIET TO MINOR STORM LEVELS AT HIGH LATITUDES. ALTHOUGH
MOST OF THE LAST 24 HOURS WAS QUIET, AN INTERVAL OF ENHANCED
ACTIVITY OCCURRED FROM 0300-1200Z. REAL-TIME SOLAR WIND DATA
INDICATED THAT A SECTOR BOUNDARY CROSSING OCCURRED SHORTLY AFTER
03Z, AND WAS FOLLOWED BY FLUCTUATING INTERPLANETARY MAGNETIC FIELD
CONDITIONS THAT INCLUDED SOME MODERATE NEGATIVE BZ.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE MOSTLY QUIET TO UNSETTLED FOR THE NEXT THREE DAYS.
III. Event Probabilities 22 JUL to 24 JUL
| Class M | 20% | 20% | 20% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 JUL 110 Predicted 22 JUL-24 JUL 112/112/115 90 Day Mean 21 JUL 107
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 JUL 003/006 ESTIMATED AFR/AP 21 JUL 010/009 PREDICTED AFR/AP 22 JUL-24 JUL 010/010-010/008-005/007
VI. Geomagnetic Activity Probabilities 22 JUL to 24 JUL
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 20% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 20% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
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