:Product: Weekly Highlights and Forecasts
:Issued: 1999 Oct 12 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
04 - 10 OCTOBER 1999

SOLAR ACTIVITY WAS LOW. ISOLATED B- AND C-CLASS SUBFLARES OCCURRED
EACH DAY. THE DISK WAS POPULATED BY NUMEROUS SMALL,
SIMPLY-STRUCTURED SUNSPOT GROUPS DURING MOST OF THE PERIOD. HOWEVER,
REGION 8728 (N22, L=318, CLASS/AREA DHO/340 ON 10 OCTOBER) ROTATED
INTO VIEW ON 08 OCTOBER, THEN GREW STEADILY THROUGH THE REST OF THE
PERIOD TO BECOME A GROUP OF MODERATE SIZE AND MAGNETIC COMPLEXITY.

REAL-TIME SOLAR WIND DATA WERE AVAILABLE FROM THE ADVANCED
COMPOSITION EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD.
VELOCITY INCREASES WERE NOTED ON 05 OCTOBER (440 TO 600 KM/SEC) AND
AGAIN ON 10 OCTOBER (420 TO 680 KM/SEC). IMF BZ BECAME MORE VARIABLE
ON 05 AND 10 OCTOBER AS WELL, WITH SOUTHERLY DEFLECTIONS TO MINUS 12
NT AND MINUS 14 NT (GSM), RESPECTIVELY. THE VELOCITY AND IMF BZ
VARIATIONS APPEARED TO BE DUE TO CORONAL HOLE EFFECTS. PHI DATA
INDICATED THAT WE SHIFTED FROM A TOWARD (NEGATIVE POLARITY) TO AN
AWAY (POSITIVE POLARITY) SOLAR SECTOR ON 10 OCTOBER.

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

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

THE GEOMAGNETIC FIELD WAS AT MOSTLY QUIET TO UNSETTLED LEVELS THROUGH
09 OCTOBER, ALTHOUGH BRIEF ACTIVE PERIODS OCCURRED DURING 04 - 05
OCTOBER. THE FIELD BECAME DISTURBED ON 10 OCTOBER WITH ACTIVE TO
MINOR STORM LEVELS DETECTED AT MIDDLE LATITUDES AND ACTIVE TO SEVERE
STORM LEVELS AT HIGH LATITUDES. THIS ACTIVITY APPEARED TO BE CORONAL
HOLE-RELATED.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
13 OCTOBER - 08 NOVEMBER 1999

SOLAR ACTIVITY IS EXPECTED TO BE PREDOMINATELY LOW. HOWEVER, REGION
8728 MAY PRODUCE ISOLATED M-CLASS FLARES BEFORE IT DEPARTS THE DISK
ON 21 OCTOBER.

NO SIGNIFICANT PROTON EVENTS ARE EXPECTED AT GEOSYNCHRONOUS ORBIT.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ALTITUDE IS
EXPECTED TO BE AT MODERATE TO HIGH LEVELS DURING 13 - 18 AND 25 - 29
OCTOBER, AND 07 - 08 NOVEMBER. OTHERWISE, FLUXES ARE EXPECTED TO BE
IN THE NORMAL TO MODERATE RANGE.

THE GEOMAGNETIC FIELD IS EXPECTED TO AT ACTIVE TO MINOR STORM LEVELS
DURING 13 - 16 AND 24 - 27 OCTOBER, AND 06 - 08 NOVEMBER DUE TO
CORONAL HOLE EFFECTS.

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