Viewing archive of Sunday, 25 July 1999
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 1999 Jul 25 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 206 Issued at 2200Z on 25 JUL 1999IA. Analysis of Solar Active Regions and Activity from 24-2100Z to 25-2100Z
SOLAR ACTIVITY WAS MODERATE. REGION 8639 (N38W86)
PRODUCED A MODERATE DURATION M2/SF AT 25/1338Z. THIS EVENT WAS
ACCOMPANIED BY TYPE II/IV SWEPT FREQUENCY BURSTS, A 600 SFU BURST AT
10 CM, AND A LOOP PROMINENCE SYSTEM. DUE TO FORESHORTENING, LITTLE
IS KNOWN ABOUT THE EVOLUTION OF THIS REGION. REGION 8645 (S27E60)
GENERATED AN M1/1F AT 25/0432Z. THIS REGION APPEARED AS A MODERATE
SIZE F CLASS GROUP. IT IS LIKELY THAT THERE IS SOME MAGNETIC
COMPLEXITY IN THIS AREA. REGION 8636 (N21W27) GENERATED A C8/SF AT
25/0103Z. MAGNETIC FIELD MIXING INCREASED SLIGHTLY IN THIS REGION
AND SPOT AREA INCREASED IN THE LEADER.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD CONTINUE AT A
MODERATE LEVEL FOR THE NEXT THREE DAYS WITH M-CLASS EVENTS POSSIBLE
FROM REGIONS 8645, 8636, AND 8639. AN ISOLATED X-CLASS EVENT IS
POSSIBLE FROM REGION 8636 OR 8645.
IIA. Geophysical Activity Summary 24-2100Z to 25-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. SOLAR WIND VELOCITY
DROPPED TO NORMAL VALUES DURING THE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE PREDOMINANTLY QUIET TO UNSETTLED FOR THE NEXT THREE
DAYS. AT HIGH LATITUDES, SOME ACTIVE CONDITIONS MAY BE EXPERIENCED
ON 28 JUL. THERE IS A SLIGHT POSSIBILITY THAT A MAJOR FLARE FROM
REGION 8636 COULD CAUSE AN ENERGETIC SOLAR PROTON EVENT AT EARTH.
III. Event Probabilities 26 JUL to 28 JUL
| Class M | 90% | 90% | 90% |
| Class X | 20% | 20% | 20% |
| Proton | 20% | 20% | 20% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 25 JUL 182 Predicted 26 JUL-28 JUL 180/182/184 90 Day Mean 25 JUL 157
V. Geomagnetic A Indices
OBSERVED AFR/AP 24 JUL 008/011 ESTIMATED AFR/AP 25 JUL 008/012 PREDICTED AFR/AP 26 JUL-28 JUL 008/007-008/007-008/015
VI. Geomagnetic Activity Probabilities 26 JUL to 28 JUL
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 10% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 20% |
| Minor storm | 05% | 05% | 10% |
| Major-severe storm | 01% | 01% | 05% |
All times in UTC
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