Viewing archive of Wednesday, 15 September 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 Sep 15 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 258 Issued at 2200Z on 15 SEP 1999IA. Analysis of Solar Active Regions and Activity from 14-2100Z to 15-2100Z SOLAR ACTIVITY WAS LOW. A LONG DURATION OPTICALLY
UNCORRELATED C2.9 X-RAY EVENT WAS THE LARGEST EVENT OF THE PERIOD.
INFREQUENT MINOR C-CLASS X-RAY EVENTS WERE OBSERVED, MOSTLY WITHOUT
OPTICAL CORRELATION. REGION 8700 (N14E45) APPEARS AS THE MOST ACTIVE
REGION ON THE VISIBLE DISK, UNDERGOING SEVERAL BRIGHTNESS
FLUCTUATIONS AND SUBFLARES. REGION 8690 (N15W48) CONTINUES TO SLOWLY
GROW AND APPEARS TO HAVE BECOME MORE MAGNETICALLY COMPLEX. REMAINING
REGIONS WERE STABLE OR IN DECAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO CONTINUE
AT LOW LEVELS. REGIONS 8690 AND 8700 WILL LIKELY PRODUCE C-CLASS
EVENTS WITH A SMALL CHANCE FOR AN ISOLATED M-CLASS FLARE.
IIA. Geophysical Activity Summary 14-2100Z to 15-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE PRIOR TO A SHOCK ARRIVAL AT
15/0700Z. A SHORT PERIOD OF SUSTAINED SOUTHWARD BZ WITH A 700 KM/S
WINDSPEED FOLLOWED THE SHOCK ARRIVAL AND RESULTED IN MINOR STORM
CONDITIONS AT MID LATITUDES WITH SEVERE STORMING AT HIGH LATITUDES.
QUIET TO ACTIVE CONDITIONS RETURNED TO ALL LATITUDES AFTER
15/1200UT. A SUDDEN IMPULSE OF 8NT WAS OBSERVED AT 15/2019UT.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE AT QUIET TO ACTIVE LEVELS DURING DAYTIME HOURS AND
ACTIVE TO MINOR STORM LEVELS DURING LOCAL NIGHTTIME. THIS
DISTURBANCE WILL BEGIN TO SUBSIDE ON DAY ONE THROUGH DAY TWO. QUIET
TO UNSETTLED CONDITIONS ARE LIKELY ON DAY THREE.
III. Event Probabilities 16 SEP to 18 SEP
| Class M | 15% | 15% | 15% |
| Class X | 05% | 05% | 05% |
| Proton | 05% | 05% | 05% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 15 SEP 155 Predicted 16 SEP-18 SEP 160/165/170 90 Day Mean 15 SEP 164
V. Geomagnetic A Indices
OBSERVED AFR/AP 14 SEP 022/023 ESTIMATED AFR/AP 15 SEP 026/030 PREDICTED AFR/AP 16 SEP-18 SEP 022/020-012/015-008/012
VI. Geomagnetic Activity Probabilities 16 SEP to 18 SEP
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 50% | 35% | 25% |
| Minor storm | 30% | 15% | 10% |
| Major-severe storm | 05% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 60% | 40% | 30% |
| Minor storm | 30% | 20% | 10% |
| Major-severe storm | 10% | 05% | 05% |
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