:Product: Weekly Highlights and Forecasts
:Issued: 1999 Dec 07 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
29 NOVEMBER - 05 DECEMBER 1999

SOLAR ACTIVITY WAS MODERATE ON 29 NOVEMBER, BUT DECREASED TO LOW
LEVELS DURING THE REST OF THE WEEK. REGION 8773 (S15, L = 164,
CLASS/AREA DRO/030 ON 26 NOVEMBER) PRODUCED AN IMPULSIVE M1/SF FLARE
AT 29/1414UT AS IT ROUNDED THE WEST LIMB. THERE WERE A FEW SMALL- TO
MODERATE-SIZED SUNSPOT GROUPS THAT PRODUCED OCCASIONAL C-CLASS
FLARES DURING THE REST OF THE PERIOD. TWO EVENTS OF INTEREST WERE A
C3 X-RAY FLARE AT 05/2221UT WITH AN ASSOCIATED TYPE II RADIO SWEEP
AND AN OPTICALLY UNCORRELATED TYPE II RADIO SWEEP AT 05/2332UT.

REAL-TIME SOLAR WIND DATA WERE AVAILABLE FROM THE ADVANCED
COMPOSITION EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD.
RECURRENT CORONAL HOLE EFFECTS BEGAN ON 03 DECEMBER AND CONTINUED
THROUGH THE REMAINDER OF THE PERIOD. SOLAR WIND SPEEDS STEADILY
INCREASED DURING 03 - 04 DECEMBER AND BRIEFLY REACHED 790 KM/SEC
LATE ON 04 DECEMBER BEFORE SLOWLY DECLINING. SUSTAINED PERIODS OF
SOUTHWARD IMF BZ ALSO OCCURRED DURING 03 - 04 DECEMBER WITH MAXIMUM
DEFLECTIONS TO MINUS 17 NT (GSM) DETECTED LATE ON 04 DECEMBER.
PARTICLE DENSITIES DROPPED TO 01 TO 03 P/CC DURING 04 - 05 DECEMBER.
A SHIFT TO AN AWAY (POSITIVE POLARITY) SOLAR SECTOR ALSO ACCOMPANIED
THE TRANSITION TO THE CORONAL HOLE WIND STREAM.

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

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT WAS
MOSTLY NORMAL THROUGH 03 DECEMBER. FLUX LEVELS INCREASED DURING THE
REST OF THE PERIOD AND REACHED HIGH LEVELS BY 05 DECEMBER.

GEOMAGNETIC FIELD ACTIVITY WAS AT QUIET TO UNSETTLED LEVELS THROUGH
02 DECEMBER. THE FIELD WAS DISTURBED DURING 03 - 05 DECEMBER DUE TO
CORONAL HOLE EFFECTS. ACTIVE TO MINOR STORM LEVELS OCCURRED DURING
THE DISTURBANCE WITH BRIEF MAJOR STORM PERIODS DETECTED AT HIGH
LATITUDES.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
08 DECEMBER 1999 - 03 JANUARY 2000

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 ARE ALSO CHANCES FOR ISOLATED MAJOR
FLARES AS POTENTIALLY ACTIVE REGIONS 8765, 8766, AND 8771 ARE DUE TO
RETURN ON 7-13 DECEMBER.

THERE IS A CHANCE FOR A SOLAR PROTON EVENT AT GEOSYNCHRONOUS ORBIT
WHEN THE ABOVE MENTIONED REGIONS RETURN STARTING ON 07 DECEMBER.

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

THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT UNSETTLED TO ACTIVE LEVELS
DURING 08 DECEMBER AS RECURRENT CORONAL HOLE EFFECTS CONTINUE.
ACTIVE LEVELS ARE POSSIBLE DURING 09 - 10 DECEMBER DUE TO CME
EFFECTS. OTHERWISE, ACTIVITY IS EXPECTED TO VARY BETWEEN QUIET AND
UNSETTLED LEVELS (BARRING ANY EARTH-DIRECTED CORONAL MASS
EJECTIONS).


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