Viewing archive of Saturday, 20 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 20 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 324 Issued at 2200Z on 20 NOV 1999

IA. Analysis of Solar Active Regions and Activity from 19-2100Z to 20-2100Z

SOLAR ACTIVITY REMAINED AT LOW LEVELS. SEVERAL SUBFLARES OCCURRED DURING THE PERIOD, A FEW OF WHICH REACHED C-CLASS. REGION 8771 (S17E12) WAS RESPONSIBLE FOR MOST OF THE SUBFLARE ACTIVITY. IT SHOWED NO SIGNIFICANT CHANGES AND MAINTAINED A MIXED-POLARITY STRUCTURE, POSSIBLY INCLUDING A DELTA CONFIGURATION. REGION 8765 (S13W47) WAS STABLE, BUT REMAINED THE LARGEST AND MOST MAGNETICALLY COMPLEX GROUP ON THE DISK WITH STRONG DELTA CONFIGURATIONS OBSERVED WITHIN ITS INTERMEDIATE AND TRAILER SPOTS. REGION 8766 (N18W25) SHOWED A SLIGHT INCREASE IN MAGNETIC FIELD STRENGTH AND MAINTAINED A MIXED-POLARITY STRUCTURE, POSSIBLY INCLUDING A DELTA CONFIGURATION WITHIN ITS TRAILER SPOTS. REGION 8759 (N12W92) WAS STABLE AS IT DEPARTED THE WEST LIMB. NEW REGION 8776 (S31E24) WAS NUMBERED.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE MODERATE. REGIONS 8765, 8766, AND 8771 EACH APPEAR CAPABLE OF PRODUCING M-CLASS FLARES. THERE IS ALSO A CHANCE FOR A MAJOR FLARE DURING THE PERIOD, ESPECIALLY FROM REGION 8765.
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
GEOMAGNETIC FIELD ACTIVITY RANGED FROM QUIET TO ACTIVE LEVELS. A UNSETTLED TO ACTIVE PERIOD OCCURRED DURING 20/0100 - 0300Z WITH MINOR STORM LEVELS DETECTED AT SOME HIGH LATITUDE STATIONS. THIS ACTIVITY FOLLOWED A BRIEF INCREASE IN SOLAR WIND VELOCITIES.
IIB. Geophysical Activity Forecast
GEOMAGNETIC ACTIVITY IS EXPECTED TO RANGE FROM UNSETTLED TO ACTIVE LEVELS. ACTIVE LEVELS ARE POSSIBLE ON DAY ONE IN RESPONSE TO RECENT CME ACTIVITY AND AGAIN ON DAY THREE DUE TO CORONAL HOLE EFFECTS.
III. Event Probabilities 21 NOV to 23 NOV
Class M80%80%80%
Class X30%30%30%
Proton20%20%20%
PCAFYELLOW
IV. Penticton 10.7 cm Flux
  Observed       20 NOV 204
  Predicted   21 NOV-23 NOV  200/200/190
  90 Day Mean        20 NOV 167
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 NOV  009/012
ESTIMATED AFR/AP 20 NOV  012/012
PREDICTED AFR/AP 21 NOV-23 NOV  015/018-012/015-015/018
VI. Geomagnetic Activity Probabilities 21 NOV to 23 NOV
A. Middle Latitudes
Active30%20%35%
Minor storm15%10%15%
Major-severe storm01%01%01%
B. High Latitudes
Active40%30%40%
Minor storm20%15%20%
Major-severe storm01%01%01%

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