Viewing archive of Wednesday, 4 August 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 Aug 04 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.comJoint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 216 Issued at 2200Z on 04 AUG 1999
IA. Analysis of Solar Active Regions and Activity from 03-2100Z to 04-2100Z
SOLAR ACTIVITY REMAINED AT HIGH LEVELS. REGION 8647
(S18W75) PRODUCED AN M6/1N FLARE AT 04/0557Z ASSOCIATED WITH A WEAK
TYPE II RADIO SWEEP (EST. SHOCK VELOCITY 400 KM/SEC) AND A 230 SFU
TENFLARE. IT ALSO PRODUCED AN M1/SF FLARE AT 04/1607Z. THIS REGION
SHOWED LITTLE CHANGE DURING THE PERIOD AND WAS OF MODERATE SIZE AND
MAGNETIC COMPLEXITY. REGION 8651 (N25W31) REMAINED A LARGE F-TYPE
GROUP OF MODERATE MAGNETIC COMPLEXITY, BUT APPEARED TO BE SLOWLY
DECAYING. IT PRODUCED TWO SUBFLARES DURING THE PERIOD. REGION 8645
(S26W66) REMAINED MODERATE IN SIZE AND MAGNETIC COMPLEXITY AND
SHOWED LITTLE CHANGE AS IT PRODUCED ISOLATED SUBFLARES. NEW REGION
8660 (S34W25), A SMALL B-TYPE GROUP, WAS NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE. ISOLATED M-CLASS FLARES ARE POSSIBLE FROM REGIONS 8645,
8647, AND 8651. THERE IS ALSO A CHANCE FOR ANOTHER MAJOR FLARE FROM
REGION 8647.
IIA. Geophysical Activity Summary 03-2100Z to 04-2100Z
THE GEOMAGNETIC FIELD WAS AT QUIET TO ACTIVE LEVELS. A SUDDEN IMPULSE
OCCURRED AT 04/0225Z (25 NT, AS MEASURED BY THE BOULDER USGS
MAGNETOMETER). FIELD ACTIVITY INCREASED FOLLOWING THE IMPULSE WITH
ACTIVE LEVELS DETECTED DURING THE 04/0300 - 0600Z INTERVAL. ACTIVITY
DECREASED TO QUIET TO UNSETTLED LEVELS DURING THE REMAINDER OF THE
PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT QUIET TO UNSETTLED LEVELS THROUGH THE PERIOD.
THERE APPEARED TO BE NO EARTH-DIRECTED CORONAL MASS EJECTIONS
ASSOCIATED WITH THE MAJOR FLARES OF 02 AND 04 AUGUST.
III. Event Probabilities 05 AUG to 07 AUG
Class M | 80% | 70% | 50% |
Class X | 20% | 15% | 10% |
Proton | 10% | 10% | 05% |
PCAF | GREEN
|
IV. Penticton 10.7 cm Flux
Observed 04 AUG 200
Predicted 05 AUG-07 AUG 195/185/175
90 Day Mean 04 AUG 165
V. Geomagnetic A Indices
OBSERVED AFR/AP 03 AUG 005/008
ESTIMATED AFR/AP 04 AUG 012/015
PREDICTED AFR/AP 05 AUG-07 AUG 012/015-010/010-005/008
VI. Geomagnetic Activity Probabilities 05 AUG to 07 AUG
A. Middle Latitudes |
Active | 25% | 20% | 15% |
Minor storm | 05% | 05% | 01% |
Major-severe storm | 01% | 01% | 01% |
B. High Latitudes |
Active | 25% | 25% | 15% |
Minor storm | 10% | 10% | 05% |
Major-severe storm | 01% | 01% | 01% |
All times in UTC
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