:Product: Weekly Highlights and Forecasts
:Issued: 1999 Nov 16 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
08 - 14 NOVEMBER 1999

SOLAR ACTIVITY WAS MODERATE DURING MOST OF THE PERIOD, BUT INCREASED
TO HIGH LEVELS ON 14 NOVEMBER. ACTIVITY ROSE TO HIGH LEVELS ON 14
NOVEMBER DUE TO A PAIR OF MAJOR FLARES. THE FIRST WAS AN M8/2B AT
14/1801UT FROM REGION 8763 (S14, L=249, CLASS/AREA DAO/170 ON 11
NOVEMBER). THE SECOND WAS AN M5/2N AT 14/1607UT FROM REGION 8766
(N18, L=210, CLASS/AREA DAO/190 ON 14 NOVEMBER). BOTH FLARES WERE
IMPULSIVE AND WERE ASSOCIATED WITH RELATIVELY MINOR DISCRETE RADIO
EMISSION. THERE WERE SEVERAL REGIONS ON THE DISK (INCLUDING THOSE
MENTIONED ABOVE) THAT PRODUCED ISOLATED M-CLASS SUBFLARES DURING THE
PERIOD (SEE THE ENERGETIC EVENT SUMMARY FOR EVENT TIMES). ALL OF
THESE REGIONS EXHIBITED MIXED-POLARITY MAGNETIC STRUCTURES OF
VARYING COMPLEXITY. REGIONS 8759 (N10, L=287, CLASS/AREA FKC/920 ON
09 NOVEMBER), 8765 (S12, L=235, CLASS/AREA EKC/640 ON 14 NOVEMBER,
AND 8766 (N18, L=210, CLASS/AREA DAO/190 ON 14 NOVEMBER) ALSO
CONTAINED MAGNETIC DELTA CONFIGURATIONS.

REAL-TIME SOLAR WIND DATA WERE AVAILABLE FROM THE ADVANCED
COMPOSITION EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD.
CORONAL HOLE EFFECTS WERE OBSERVED DURING 08 - 11 NOVEMBER WITH
VELOCITIES PEAKING AT 760 KM/SEC AND IMF BZ RANGING FROM PLUS 09 NT
(GSM) TO MINUS 08 NT. CORONAL HOLE EFFECTS SUBSIDED ON 12 NOVEMBER.
A CHANGE IN WIND FLOW CHARACTERISTICS OCCURRED AROUND 12/1600UT
FOLLOWED BY INCREASED SOUTHWARD IMF BZ (MAXIMUM SOUTHERLY
DEFLECTIONS TO MINUS 12 NT), HIGHLY VARIABLE SOLAR SECTOR
ORIENTATION, AND MINOR VELOCITY INCREASES.

NO PROTON EVENTS WERE DETECTED AT GEOSYNCHRONOUS ORBIT DURING THE
PERIOD.

THE GREATER THAN 2 MEV ELECTRON FLUX WAS AT MODERATE TO HIGH LEVELS
DURING 09 - 13 NOVEMBER. OTHERWISE, FLUXES WERE AT NORMAL TO
MODERATE LEVELS.

THE GEOMAGNETIC FIELD WAS DISTURBED DURING 08 - 11 NOVEMBER DUE TO
CORONAL HOLE EFFECTS WITH ACTIVE TO MINOR STORM LEVELS DETECTED AT
MIDDLE LATITUDES AND ACTIVE TO MAJOR STORM LEVELS AT HIGH LATITUDES.
THE WERE ALSO LOCALIZED SEVERE STORM PERIODS AT HIGH LATITUDES
DURING THE DISTURBANCE. ACTIVITY DECREASED TO QUIET TO UNSETTLED
LEVELS ON 12 NOVEMBER AS CORONAL HOLE EFFECTS SUBSIDED. ANOTHER
DISTURBANCE OCCURRED DURING 13 NOVEMBER DUE TO A SUSTAINED PERIOD OF
SOUTHWARD IMF BZ (SEE THE SOLAR WIND DISCUSSION ABOVE). ACTIVITY
DECREASED TO MOSTLY QUIET TO UNSETTLED LEVELS ON THE FINAL DAY OF
THE PERIOD.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
17 NOVEMBER - 13 DECEMBER 1999

SOLAR ACTIVITY IS EXPECTED TO RANGE FROM LOW TO HIGH LEVELS. FREQUENT
C-CLASS FLARES ARE LIKELY. ISOLATED M-CLASS FLARES WILL BE POSSIBLE
THROUGHOUT THE PERIOD. THERE IS ALSO A GOOD CHANCE FOR ISOLATED
MAJOR FLARES THROUGH 25 NOVEMBER, PRINCIPALLY FROM REGIONS 8765 AND
8766. BOTH REGIONS WERE GROWING IN SIZE AND COMPLEXITY AS THE PERIOD
ENDED.

THERE IS A CHANCE FOR A SOLAR PROTON EVENT AT GEOSYNCHRONOUS ORBIT
THROUGH 25 NOVEMBER DUE TO THE MAJOR FLARE POTENTIAL IN REGIONS 8765
AND 8766. REGION 8759 ALSO PROVIDES A SLIGHT CHANCE FOR A PROTON
EVENT.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ALTITUDE IS
EXPECTED TO BE AT MODERATE TO HIGH LEVELS DURING 05 - 10 DECEMBER
WITH NORMAL TO MODERATE LEVELS DURING THE REMAINDER OF THE PERIOD.

THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT UNSETTLED TO MINOR STORM
LEVELS DURING 04 - 08 DECEMBER DUE TO RECURRENT CORONAL HOLE
EFFECTS. OTHERWISE, ACTIVITY IS EXPECTED TO VARY BETWEEN QUIET AND
UNSETTLED LEVELS (BARRING ANY EARTH-DIRECTED CORONAL MASS
EJECTIONS).

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