Viewing archive of Monday, 26 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 26 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 207 Issued at 2200Z on 26 JUL 1999IA. Analysis of Solar Active Regions and Activity from 25-2100Z to 26-2100Z
SOLAR ACTIVITY BECAME LOW. THE LARGEST EVENTS OF THE
PERIOD WERE LOW LEVEL C-CLASS BURSTS. REGION 8636 (N21W41) PRODUCED
SEVERAL SUBFLARES, DECREASED SLIGHTLY IN SIZE, AND APPEARED TO ONCE
AGAIN SIMPLIFY MAGNETICALLY. REGION 8645 (S27E47) REMAINED
PREDOMINANTLY STABLE. REGION 8639 (N38W99) PRODUCED FREQUENT
SURGING FROM BEHIND THE LIMB BUT PRODUCED NO DISCERNIBLE BURSTS.
POST EVENT ANALYSIS OF THE M2 FLARE GENERATED BY THIS REGION AT
25/1338Z INDICATED A LARGE CORONAL MASS EJECTION ACCOMPANIED THE
FLARE. HOWEVER, IT WAS DETERMINED BY SOHO SCIENTISTS THAT THIS CME
WAS NOT EARTH DIRECTED.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS FORECAST TO BE LOW
TO MODERATE. BOTH REGIONS 8636 AND 8645 ARE CAPABLE OF PRODUCING
OCCASIONAL M-CLASS EVENTS. REGION 8636 COULD PRODUCE AN ISOLATED
X-CLASS EVENT BUT THAT LIKELIHOOD IS DECREASING AS THE REGION SLOWLY
DECAYS.
IIA. Geophysical Activity Summary 25-2100Z to 26-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD
REMAIN AT GENERALLY QUIET TO UNSETTLED LEVELS FOR THE NEXT THREE
DAYS. ISOLATED ACTIVE PERIODS ARE POSSIBLE DURING THAT TIME.
III. Event Probabilities 27 JUL to 29 JUL
| Class M | 75% | 75% | 75% |
| Class X | 15% | 15% | 15% |
| Proton | 15% | 15% | 15% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 26 JUL 172 Predicted 27 JUL-29 JUL 172/172/174 90 Day Mean 26 JUL 158
V. Geomagnetic A Indices
OBSERVED AFR/AP 25 JUL 008/008 ESTIMATED AFR/AP 26 JUL 008/007 PREDICTED AFR/AP 27 JUL-29 JUL 008/007-010/012-008/008
VI. Geomagnetic Activity Probabilities 27 JUL to 29 JUL
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 30% | 15% |
| Minor storm | 05% | 15% | 05% |
| Major-severe storm | 01% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 10% | 30% | 20% |
| Minor storm | 05% | 15% | 05% |
| Major-severe storm | 01% | 05% | 01% |
All times in UTC
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