:Product: Weekly Highlights and Forecasts
:Issued: 2000 Jan 04 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
27 DECEMBER 1999 - 02 JANUARY 2000

SOLAR ACTIVITY RANGED FROM LOW TO MODERATE LEVELS. ACTIVITY WAS AT
MODERATE LEVELS DURING 27 - 28 DECEMBER AS REGION 8806 (N19, L =
114, CLASS/AREA FHC/1100 ON 23 DECEMBER) PRODUCED THREE M-CLASS
FLARES. THE FLARES INCLUDED A M1/1N AT 27/0154UT WITH AN ASSOCIATED
TYPE II RADIO SWEEP, A M2/SN AT 27/1206UT, AND A M4/2B
PARALLEL-RIBBON FLARE AT 28/0048UT ACCOMPANIED BY A TYPE II RADIO
SWEEP AND A 1400 SFU TENFLARE. REGION 8806 WAS LARGE AND
MAGNETICALLY COMPLEX, BUT IN A STATE OF GRADUAL DECAY AS THE PERIOD
BEGAN. IT CONTINUED TO DECAY UNTIL IT CROSSED THE WEST LIMB ON 29
DECEMBER. ACTIVITY DECREASED TO LOW LEVELS FOLLOWING THE PASSAGE OF
REGION 8806. AS THE PERIOD ENDED, THE VISIBLE DISK WAS POPULATED BY
FOUR STABLE, SIMPLY-STRUCTURED SUNSPOT GROUPS.

REAL-TIME SOLAR WIND DATA WERE AVAILABLE FROM THE NASA ADVANCED
COMPOSITION EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD. A
RECURRENT, HIGH-SPEED CORONAL HOLE WIND STREAM BEGAN TO AFFECT EARTH
DURING THE LATTER HALF OF 30 DECEMBER, WITH EFFECTS CONTINUING
THROUGH THE REMAINDER OF THE PERIOD. CORONAL HOLE EFFECTS INCLUDED
ELEVATED VELOCITIES WITH PEAKS TO 800 KM/SEC, LOW PARTICLE DENSITIES
(01 TO 03 P/CC), FREQUENT NORTH/SOUTH FLUCTUATIONS OF IMF BZ WITH
MAXIMUM SOUTHWARD DEFLECTIONS TO MINUS 17 NT (GSM), AND A SHIFT TO
AN AWAY (POSITIVE POLARITY) SOLAR SECTOR.

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

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT REACHED
HIGH LEVELS DURING 01 - 02 JANUARY.

THE GEOMAGNETIC FIELD WAS DISTURBED DURING 30 DECEMBER - 02 JANUARY
DUE TO A RECURRENT CORONAL HOLE WIND STREAM. FIELD ACTIVITY RANGED
FROM UNSETTLED TO MINOR STORM LEVELS DURING THE DISTURBANCE WITH
MAJOR STORM LEVELS DETECTED AT HIGH LATITUDES.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
05 - 31 JANUARY 2000

SOLAR ACTIVITY IS EXPECTED TO RANGE FROM LOW TO MODERATE LEVELS
DURING MOST OF THE PERIOD. OCCASIONAL TO FREQUENT C-CLASS FLARES AND
ISOLATED M-CLASS FLARES ARE LIKELY THROUGHOUT THE PERIOD.  IN
ADDITION, THERE WILL BE AN INCREASED CHANCE FOR ISOLATED MAJOR FLARE
ACTIVITY DURING 08 - 26 JANUARY WITH THE EXPECTED RETURN OF OLD
REGIONS 8798 (S13, L = 171) AND 8806 (N19, L = 115).

THERE WILL BE AN INCREASED CHANCE FOR A PROTON EVENT AT
GEOSYNCHRONOUS ORBIT DURING 08 - 26 JANUARY.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS
EXPECTED TO BE AT MODERATE TO HIGH LEVELS THROUGH 05 JANUARY. NORMAL
TO MODERATE LEVELS ARE EXPECTED DURING 06 - 27 JANUARY. FLUXES ARE
EXPECTED TO INCREASE TO MODERATE TO HIGH LEVELS DURING 28 - 31
JANUARY.

GEOMAGNETIC FIELD ACTIVITY IS EXPECTED TO BE AT QUIET TO UNSETTLED
LEVELS THROUGH 26 JANUARY, BARRING AN EARTH-DIRECTED CME. ACTIVE TO
MINOR STORM LEVELS ARE EXPECTED DURING 27 - 30 JANUARY DUE TO
RECURRENT CORONAL HOLE EFFECTS.


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