:Product: Weekly Highlights and Forecasts
:Issued: 1999 Aug 24 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
16 - 22 AUGUST 1999

SOLAR ACTIVITY RANGED FROM LOW TO HIGH LEVELS. ACTIVITY WAS AT LOW
LEVELS THROUGH 18 AUGUST WITH A FEW LONG-DURATION C-CLASS FLARES
DETECTED. ACTIVITY INCREASED TO MODERATE LEVELS ON 19 AUGUST BY
VIRTUE OF AN ISOLATED M1/1N FLARE AT 19/1205UT FROM REGION 8672
(N15, L=347, CLASS/AREA CRO/040 ON 19 AUGUST). ACTIVITY ROSE TO HIGH
LEVELS ON 20 AUGUST AS REGION 8674 (S25, L=247, CLASS/AREA DKO/490
ON 22 AUGUST) PRODUCED AN IMPULSIVE M9/1N FLARE AT 20/2308UT WITH AN
ASSOCIATED TYPE II RADIO SWEEP AND 480 SFU TENFLARE. THIS REGION
PRODUCED ANOTHER MAJOR FLARE ON 21 AUGUST, AN IMPULSIVE M5/1N AT
21/2214UT ACCOMPANIED BY A 250 SFU TENFLARE. ACTIVITY DROPPED TO LOW
LEVELS ON 22 AUGUST WITH A FEW C-CLASS FLARES FROM REGION 8674
INCLUDING A C5/SN FLARE AT 22/1412UT WITH TYPES II AND IV RADIO
SWEEPS.

REAL-TIME SOLAR WIND DATA WERE AVAILABLE FROM THE ADVANCED
COMPOSITION EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD. A
CORONAL HOLE SIGNATURE WAS EVIDENT THROUGH 20 AUGUST WITH HIGH WIND
SPEEDS (PEAK 820 KM/SECOND ON 19 AUGUST), ELEVATED PROTON
TEMPERATURES, AND LOW DENSITIES COMBINED WITH PERIODS OF SUSTAINED
SOUTHWARD IMF BZ (MAXIMUM SOUTHERLY DEFLECTIONS TO MINUS 14 NT
(GSM)).

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

THE GREATER THAN 2 MEV ELECTRON FLUX WAS AT NORMAL LEVELS AT THE
START OF THE PERIOD, THEN ROSE TO HIGH LEVELS ON 17 AUGUST. FLUXES
REMAINED AT HIGH LEVELS DURING THE REMAINDER OF THE PERIOD.

A GEOMAGNETIC FIELD DISTURBANCE WAS IN PROGRESS AS THE PERIOD BEGAN
AND CONTINUED UNTIL LATE 20 AUGUST. ACTIVE TO MINOR STORM LEVELS
OCCURRED DURING THE DISTURBANCE WITH BRIEF MAJOR TO SEVERE STORM
PERIODS DETECTED AT HIGH LATITUDES. THE DISTURBANCE, WHICH ENDED
LATE ON 20 AUGUST, APPEARED TO BE DUE TO A HIGH-SPEED CORONAL HOLE
WINDSTREAM. FIELD ACTIVITY DECLINED TO QUIET TO UNSETTLED LEVELS FOR
THE REMAINDER OF THE PERIOD.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
25 AUGUST - 20 SEPTEMBER 1999

SOLAR ACTIVITY IS EXPECTED TO RANGE FROM LOW TO MODERATE LEVELS.
THERE WILL BE A CHANCE FOR MORE MAJOR FLARE ACTIVITY FROM REGION
8674 BEFORE IT DEPARTS THE VISIBLE DISK AROUND 01 SEPTEMBER.

THERE WILL BE A SLIGHT CHANCE FOR A PROTON EVENT AT GEO-SYNCHRONOUS
ORBIT.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEO-SYNCHRONOUS ALTITUDE IS
EXPECTED TO BE AT  MODERATE TO HIGH LEVELS DURING THE FIRST TWO
DAYS, THEN DECREASE TO NORMAL TO MODERATE LEVELS THROUGH 12
SEPTEMBER. HIGH LEVELS ARE ALSO EXPECTED AROUND 13 - 18 SEPTEMBER.
NORMAL TO MODERATE LEVELS ARE EXPECTED FOR THE REMAINDER OF THE
PERIOD.

GEOMAGNETIC FIELD ACTIVITY IS EXPECTED TO BE AT UNSETTLED TO ACTIVE
LEVELS ON 25 AUGUST. ACTIVE LEVELS ARE ALSO EXPECTED AROUND 12 - 16
SEPTEMBER. OTHERWISE, QUIET TO UNSETTLED LEVELS ARE EXPECTED.

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