Viewing archive of Tuesday, 20 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 20 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 201 Issued at 2200Z on 20 JUL 1999IA. Analysis of Solar Active Regions and Activity from 19-2100Z to 20-2100Z SOLAR ACTIVITY WAS LOW, SEVERAL C-CLASS X-RAY EVENTS
WERE OBSERVED OVER THE PAST 24 HOURS. THE LARGEST WAS A C4/SF AT
20/0026Z WHICH WAS OPTICALLY CORRELATED TO REGION 8636 (N20E36).
REGION 8636 EXHIBITED SOME GROWTH AND HAS A BETA GAMMA MAGNETIC
CONFIGURATION. REGION 8640 (N17E79), AN HSX SPOT GROUP, WAS
NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGION 8636 CONTINUES TO HAVE THE BEST POTENTIAL FOR
M-CLASS EVENTS.
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. SOLAR WIND VELOCITIES
INCREASED SLIGHLTY AFTER 20/1000Z BUT REMAINED BELOW 380 KM/S.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED. THE UNSETTLED CONDITIONS MAY BE
THE RESULT OF A CME EARLY ON THE 19TH. ISOLATED ACTIVE CONDITIONS
ARE POSSIBLE ON DAY TWO, ESPECIALLY IN THE HIGHER LATITUDES. ALSO,
SOME MINOR EFFECTS MAY OCCUR FROM A SMALL CORONAL HOLE STREAM
IMPACTING THE EARTH AS IT ENTERS THE SOLAR WESTERN HEMISPHERE.
III. Event Probabilities 21 JUL to 23 JUL
| Class M | 50% | 50% | 50% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 20 JUL 140 Predicted 21 JUL-23 JUL 145/150/160 90 Day Mean 20 JUL 153
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 JUL 003/004 ESTIMATED AFR/AP 20 JUL 006/007 PREDICTED AFR/AP 21 JUL-23 JUL 008/007-014/015-012/010
VI. Geomagnetic Activity Probabilities 21 JUL to 23 JUL
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 30% | 20% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 35% | 25% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
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