Viewing archive of Saturday, 31 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 31 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 212 Issued at 2200Z on 31 JUL 1999IA. Analysis of Solar Active Regions and Activity from 30-2100Z to 31-2100Z SOLAR ACTIVITY WAS LOW. SEVERAL C-CLASS FLARES WERE
PRODUCED BY REGION 8651 (N25E23). THE LARGEST WAS A C5/SF AT
30/2335Z. THIS REGION REMAINS THE LARGEST REGION ON THE DISK AND IS
AN E-TYPE GROUP WITH A WHITE LIGHT AREA OF AROUND 730 MILLIONTHS.
THE SECOND MOST INTERESTING GROUP IS REGION 8645 (S25W16) WHICH ALSO
PRODUCED SEVERAL C-CLASS FLARES. THIS REGION HAS MAINTAINED A WHITE
LIGHT AREA OF AROUND 600 MILLIONTHS AND IS A F-TYPE GROUP. NEW
REGION 8654 (N19W18) WAS NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGIONS 8645 AND 8651 HAVE THE POTENTIAL FOR PRODUCING
ISOLATED M-CLASS EVENTS.
IIA. Geophysical Activity Summary 30-2100Z to 31-2100Z
THE GEOMAGNETIC FIELD WAS AT QUIET TO SEVERE STORM CONDITIONS. MAJOR
TO SEVERE STORMS WERE PRESENT EARLY IN THE PERIOD WITH UNSETTLED TO
ACTIVE LEVELS PREDOMINATE TOWARD THE END.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED WITH PERIODS OF ACTIVE CONDITIONS THE FIRST
DAY OF THE FORECAST. THE SECOND AND THIRD DAYS ARE EXPECTED TO
RETURN TO QUIET TO UNSETTLED CONDITIONS.
III. Event Probabilities 01 AUG to 03 AUG
| Class M | 80% | 80% | 80% |
| Class X | 15% | 15% | 15% |
| Proton | 10% | 10% | 10% |
| PCAF | YELLOW | ||
IV. Penticton 10.7 cm Flux
Observed 31 JUL 201 Predicted 01 AUG-03 AUG 195/190/190 90 Day Mean 31 JUL 162
V. Geomagnetic A Indices
OBSERVED AFR/AP 30 JUL 041/036 ESTIMATED AFR/AP 31 JUL 018/020 PREDICTED AFR/AP 01 AUG-03 AUG 015/012-008/008-008/008
VI. Geomagnetic Activity Probabilities 01 AUG to 03 AUG
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 15% | 15% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 20% | 20% |
| Minor storm | 10% | 05% | 05% |
| Major-severe storm | 05% | 01% | 01% |
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