Viewing archive of Wednesday, 17 November 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 Nov 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 321 Issued at 2200Z on 17 NOV 1999IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z SOLAR ACTIVITY WAS HIGH. TWO M-CLASS X-RAY FLARES WERE
OBSERVED. THE LARGEST, AN M7/2B FLARE FROM REGION 8766 (N17E21),
OCCURRED AT 0957Z. TYPE II AND IV RADIO SWEEPS, A 390 SFU TENFLARE,
AND OTHER DISCRETE RADIO BURSTS ACCOMPANIED THIS EVENT. THE SECOND
FLARE, AN M2/1N FROM REGION 8765 (S11E08), PEAKED AT 16/2124Z. THE
REMAINDER OF THE PERIOD SAW NUMEROUS C-CLASS SUBFLARES SUPERIMPOSED
ON AN ELEVATED BACKGROUND FLUX LEVEL OF NEARLY C2. REGION 8765
ATTAINED A WHITE-LIGHT AREA OF 1190 MILLIONTHS AND REMAINS A
BETA-GAMMA-DELTA GROUP. NEW REGION 8771 (S14W33) WAS NUMBERED
TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE
MODERATE TO HIGH. BOTH REGIONS 8765 AND 8766 HAVE THE POTENTIAL TO
GENERATE A MAJOR PROTON PRODUCING FLARE WITHIN THE NEXT FEW DAYS.
ISOLATED M-CLASS ACTIVITY IS ALSO POSSIBLE FROM REGION 8768.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED FOR THE FIRST DAY OF THE PERIOD.
BY DAYS TWO AND THREE ACTIVE TO MINOR STORM CONDITIONS ARE POSSIBLE
DUE TO CME EFFECTS. PARTIAL HALO CMES WERE OBSERVED ON SOHO/LASCO
IMAGERY YESTERDAY AND TODAY'S FLARE ACTIVITY PRODUCED RADIO CME
SIGNATURES.
III. Event Probabilities 18 NOV to 20 NOV
| Class M | 90% | 90% | 90% |
| Class X | 30% | 30% | 30% |
| Proton | 15% | 15% | 15% |
| PCAF | YELLOW | ||
IV. Penticton 10.7 cm Flux
Observed 17 NOV 221 Predicted 18 NOV-20 NOV 215/200/195 90 Day Mean 17 NOV 165
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 NOV 011/016 ESTIMATED AFR/AP 17 NOV 011/016 PREDICTED AFR/AP 18 NOV-20 NOV 012/012-020/020-020/020
VI. Geomagnetic Activity Probabilities 18 NOV to 20 NOV
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 35% | 45% | 45% |
| Minor storm | 10% | 20% | 20% |
| Major-severe storm | 05% | 10% | 10% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 40% | 50% | 50% |
| Minor storm | 20% | 25% | 25% |
| Major-severe storm | 10% | 10% | 10% |
All times in UTC
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