Viewing archive of Saturday, 17 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 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 198 Issued at 2200Z on 17 JUL 1999IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z SOLAR ACTIVITY WAS LOW. THE TWO ACTIVE REGIONS WERE
8535 (N44W92) AND 8536 (N20E73). BOTH REGIONS PRODUCED SEVERAL
OPTICAL SUBFLARES DURING THE DAY. REGION 8535 ALSO PRODUCED 2
C-CLASS EVENTS, THE LARGEST WAS A C3/SF AT 17/1631UT. REGION 8536
WAS NUMBERED TODAY. IT APPEARS TO BE RETURNING REGION 8539. THAT
REGION PRODUCED SEVERAL C AND M-CLASS EVENTS DURING THE LAST
ROTATION.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. ALTHOUGH REGION 8535 WILL ROTATE OFF OF THE DISK THIS
PERIOD, REGION 8536 COULD PRODUCE ISOLATED M-CLASS EVENTS.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
THE GEOMAGNETIC FIELD WAS QUIET.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO CONTINUE TO BE QUIET FOR THE FIRST TWO DAYS OF THE
PERIOD WITH POSSIBLE UNSETTLED CONDITIONS ON THE THIRD DAY.
III. Event Probabilities 18 JUL to 20 JUL
| Class M | 50% | 50% | 50% |
| Class X | 05% | 05% | 05% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 17 JUL 137 Predicted 18 JUL-20 JUL 150/155/160 90 Day Mean 17 JUL 152
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 JUL 005/005 ESTIMATED AFR/AP 17 JUL 005/005 PREDICTED AFR/AP 18 JUL-20 JUL 005/007-005/007-010/010
VI. Geomagnetic Activity Probabilities 18 JUL to 20 JUL
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 20% |
| Minor storm | 01% | 01% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 20% |
| Minor storm | 01% | 01% | 05% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
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