Viewing archive of Sunday, 21 November 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 Nov 21 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 325 Issued at 2200Z on 21 NOV 1999

IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z

SOLAR ACTIVITY INCREASED TO MODERATE LEVELS. REGION 8765 (S12W60) PRODUCED THREE M-CLASS FLARES, AN M1/1N AT 21/0014Z ASSOCIATED WITH A 280 SFU TENFLARE, AN M2/SN AT 21/1017Z, AND AN M3/2N AT 21/1820Z ASSOCIATED WITH A 270 SFU TENFLARE. THIS REGION SHOWED A SLIGHT DECREASE IN MAGNETIC FIELD INTENSITY, BUT REMAINED LARGE AND STRUCTURALLY COMPLEX, POSSIBLY INCLUDING A MAGNETIC DELTA CONFIGURATION WITHIN ITS INTERIOR SPOTS. REGION 8771 (S16E01) SHOWED A MAGNETIC DELTA CONFIGURATION WITHIN ITS TRAILER PORTION AND UNDERWENT MINOR DEVELOPMENT. IT PRODUCED AN M3/2B FLARE AT 20/2235Z ASSOCIATED WITH A TYPE II RADIO SWEEP (EST. VELOCITY 700 KM/SEC). REGION 8768 (N16W65) SHOWED A MINOR INCREASE IN SPOT COUNT DURING THE PERIOD AND PRODUCED ISOLATED SUBFLARES, NONE OF WHICH WERE ASSOCIATED WITH SIGNIFICANT X-RAY EMISSION. REGION 8766 (N18W36) DECAYED SLIGHTLY. THE REMAINING REGIONS WERE SMALL AND STABLE INCLUDING NEWLY NUMBERED REGIONS 8777 (S26E40) AND 8778 (S14E62).
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO REMAIN AT MODERATE LEVELS. REGIONS 8765 AND 8771 ARE EXPECTED TO PRODUCE M-CLASS FLARES. THERE IS ALSO A CHANCE FOR A MAJOR FLARE, ESPECIALLY FROM REGION 8765. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 20/2100Z TO 21/2100Z: GEOMAGNETIC FIELD ACTIVITY RANGED FROM QUIET TO MINOR STORM LEVELS. A BRIEF PERIOD OF ACTIVE TO MINOR STORM LEVELS OCCURRED AROUND 21/0600Z FOLLOWING A 3-HOUR PERIOD OF SUSTAINED SOUTHWARD IMF BZ. THE GEOMAGNETIC FIELD WAS AT QUIET TO UNSETTLED LEVELS DURING THE REST OF THE PERIOD. THE GREATER THAN 2 MEV ELECTRON FLUX BRIEFLY REACHED HIGH LEVELS LATE IN THE PERIOD.
IIB. Geophysical Activity Forecast
GEOMAGNETIC FIELD ACTIVITY IS EXPECTED TO RANGE FROM QUIET TO ACTIVE LEVELS. ACTIVE LEVELS ARE POSSIBLE DURING 23 NOVEMBER DUE TO CORONAL HOLE EFFECTS. THE GREATER THAN 2 MEV ELECTRON FLUX IS EXPECTED TO BE AT MODERATE TO HIGH LEVELS.
III. Event Probabilities 22 NOV to 24 NOV
Class M80%80%80%
Class X20%20%20%
Proton15%15%15%
PCAFYELLOW
IV. Penticton 10.7 cm Flux
  Observed       21 NOV 210
  Predicted   22 NOV-24 NOV  195/185/170
  90 Day Mean        21 NOV 167
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 NOV  007/009
ESTIMATED AFR/AP 21 NOV  015/010
PREDICTED AFR/AP 22 NOV-24 NOV  012/015-015/018-012/015
VI. Geomagnetic Activity Probabilities 22 NOV to 24 NOV
A. Middle Latitudes
Active25%35%25%
Minor storm10%15%10%
Major-severe storm01%01%01%
B. High Latitudes
Active30%40%30%
Minor storm15%20%15%
Major-severe storm01%01%01%

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