:Product: Weekly Highlights and Forecasts
:Issued: 1999 Sep 08 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
30 AUGUST - 05 SEPTEMBER 1999

SOLAR ACTIVITY RANGED FROM LOW TO MODERATE LEVELS. ACTIVITY REACHED
MODERATE LEVELS DURING THE FIRST DAY OF THE PERIOD DUE TO AN M3/2B
FLARE AT 30/1805UT WITH AN ASSOCIATED TYPE II RADIO SWEEP FROM
REGION 8681 (N21, L=207, CLASS/AREA DAI/280 ON 30 AUGUST). REGION
8681 EMERGED RAPIDLY ON 28 AUGUST AND CONTINUED TO GROW THROUGH 30
AUGUST, THEN SHOWED GRADUAL DECAY DURING THE REST OF THE PERIOD.
ACTIVITY DECLINED TO LOW LEVELS ON 31 AUGUST AND REMAINED SO DURING
THE REMAINING DAYS WITH MOST ACTIVE CENTERS EITHER STABLE OR
DECLINING. ALSO NOTEWORTHY WAS A PRECIPITOUS DROP IN THE DAILY 10.7
CM SOLAR RADIO FLUX, WHICH FELL FROM 218 TO 112 SFU DURING THE
SUMMARY PERIOD.

REAL-TIME SOLAR WIND DATA WERE AVAILABLE FROM THE ADVANCED
COMPOSITION EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD. WIND
SPEEDS WERE ELEVATED DURING THE FIRST HALF OF THE PERIOD WITH PEAKS
TO 640 KM/SEC. IMF BZ WAS SOUTHWARD DURING MUCH OF THE WEEK WITH
MAXIMUM SOUTHERLY DEFLECTIONS FROM MINUS 05 TO MINUS 09 NT. PHI DATA
INDICATED THAT EARTH WAS WITHIN AN AWAY (POSITIVE POLARITY) SOLAR
SECTOR MOST OF THE WEEK. PROTON DENSITIES WERE IN THE 02 TO 12 P/CC
RANGE.

NO PROTON EVENTS WERE DETECTED AT GEO-SYNCHRONOUS ORBIT DURING THE
PERIOD.

THE GREATER THAN 2 MEV ELECTRON FLUX WAS AT MODERATE TO HIGH LEVELS
DURING MOST OF THE PERIOD.

THE GEOMAGNETIC FIELD WAS INTERMITTENTLY DISTURBED THROUGH 04
SEPTEMBER WITH UNSETTLED TO MAJOR STORM LEVELS DETECTED (THE MAJOR
STORM PERIODS WERE LIMITED TO HIGH LATITUDES). THIS ACTIVITY
APPEARED TO BE DUE TO THE COMBINATION OF ELEVATED SOLAR WIND SPEEDS
AND SOUTHWARD IMF BZ DESCRIBED ABOVE. FIELD ACTIVITY DECLINED TO
QUIET TO UNSETTLED LEVELS ON 05 SEPTEMBER.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
08 SEPTEMBER - 04 OCTOBER 1999

SOLAR ACTIVITY IS EXPECTED TO RANGE FROM LOW TO MODERATE LEVELS WITH
A SLIGHT CHANCE FOR MAJOR FLARES. AN INCREASING TREND IS EXPECTED TO
COMMENCE AROUND 16 SEPTEMBER WITH THE RETURN OF OLD REGION 8674
(S24, L=246), WHICH PRODUCED ISOLATED MAJOR FLARES DURING ITS LAST
ROTATION.

THERE WILL BE AN INCREASED CHANCE FOR A PROTON EVENT AT
GEO-SYNCHRONOUS ORBIT BEGINNING AROUND 16 SEPTEMBER.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEO-SYNCHRONOUS ALTITUDE IS
EXPECTED TO BE AT MODERATE TO HIGH LEVELS BEGINNING AROUND 13
SEPTEMBER

GEOMAGNETIC FIELD ACTIVITY IS EXPECTED VARY FROM QUIET TO UNSETTLED
LEVELS DURING MOST OF THE PERIOD. HOWEVER, ACTIVE PERIODS WILL BE
POSSIBLE AROUND 12 - 16 SEPTEMBER AND AGAIN AROUND 26 SEPTEMBER - 01
OCTOBER DUE TO RECURRENT HIGH SPEED SOLAR WIND STREAMS.


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