:Product: Weekly Highlights and Forecasts
:Issued: 1999 Aug 10 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
02 - 08 AUGUST 1999

SOLAR ACTIVITY RANGED FROM LOW TO HIGH LEVELS. THE WEEK BEGAN WITH
ACTIVITY AT HIGH LEVELS DUE TO AN X1/1B FLARE AT 02/2128UT FROM
REGION 8647 (S18, L=242, CLASS/AREA EAO/350 ON 04 AUGUST) WITH AN
ASSOCIATED 570 SFU TENFLARE AND TYPE II RADIO SWEEP. THIS REGION WAS
ALSO RESPONSIBLE FOR THE WEEK'S SECOND MAJOR FLARE, AN M6/1N FLARE
AT 04/0557UT ACCOMPANIED BY A 230 SFU TENFLARE AND A WEAK TYPE II
RADIO SWEEP. REGION 8647 WAS PART OF A COMPLEX OF CLOSELY-SPACED,
INTERACTING REGIONS THAT INCLUDED REGION 8645 (S26, L=242,
CLASS/AREA FAO/620 ON 30 JULY). REGION 8645 WAS OF MODERATE SIZE AND
MAGNETIC COMPLEXITY AND PRODUCED A FEW LOW-LEVEL M-CLASS FLARES
DURING  ITS PASSAGE. A FEW LOW-LEVEL M-CLASS FLARES OCCURRED WITHIN
THE 8645/8647 REGION COMPLEX AS IT CROSSED THE WEST LIMB DURING 05 -
07 AUGUST. REGION 8651 (N25, L=204, CLASS/AREA FKI/1370 ON 02
AUGUST), WHICH PRODUCED A MAJOR FLARE ON 29 JULY (SEE PRF #1248),
REMAINED A LARGE GROUP OF MODERATE MAGNETIC COMPLEXITY. IT PRODUCED
A FEW SUBFLARES AS IT GRADUALLY DECAYED THROUGH THE PERIOD BEFORE
QUIETLY CROSSING THE WEST LIMB ON 08 AUGUST.

REAL-TIME SOLAR WIND DATA WERE AVAILABLE FROM THE ADVANCED
COMPOSITION EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD. TWO
WEAK CME PASSAGES WERE OBSERVED DURING THE PERIOD. THE FIRST
OCCURRED EARLY ON 04 AUGUST AND WAS CHARACTERIZED BY A SMALL JUMP IN
SOLAR WIND VELOCITIES, INCREASED PROTON DENSITIES, AND A BRIEF
PERIOD OF SOUTHWARD IMF BZ WITH MAXIMUM DEFLECTIONS TO MINUS 12 NT
(GSM). THE OTHER PASSAGE OCCURRED EARLY ON 06 AUGUST ASSOCIATED WITH
A GRADUAL VELOCITY INCREASE (320 TO 500 KM/SEC), A BRIEF DENSITY
INCREASE, AND A PERIOD OF SUSTAINED SOUTHWARD IMF BZ (MAXIMUM
DEFLECTIONS TO MINUS 12 NT). BZ REMAINED MOSTLY SOUTHWARD FOR THE
REST OF THE PERIOD.

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

THE GREATER THAN 2 MEV ELECTRON FLUX WAS AT NORMAL TO MODERATE
LEVELS.

THE GEOMAGNETIC FIELD WAS AT QUIET TO UNSETTLED LEVELS THROUGH MOST
OF THE PERIOD. THE FIELD WAS MILDLY DISTURBED ON 04 AND 06 AUGUST
WITH BRIEF ACTIVE PERIODS DETECTED AT ALL LATITUDES. THERE WERE ALSO
BRIEF MINOR STORM PERIODS DETECTED AT HIGH LATITUDES ON 06 AUGUST.
THIS ACTIVITY APPEARED TO BE IN RESPONSE TO THE WEAK CME PASSAGES
DESCRIBED ABOVE.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
11 AUGUST - 06 SEPTEMBER 1999

SOLAR ACTIVITY IS EXPECTED TO RANGE FROM LOW TO MODERATE LEVELS. AN
OVERALL INCREASING TREND IS EXPECTED TO COMMENCE AROUND 19 AUGUST
WITH THE RETURNS OF OLD REGION 8645, 8647, AND 8651. CHANCES FOR
MAJOR FLARE ACTIVITY ARE ALSO EXPECTED TO INCREASE BEGINNING ON 19
AUGUST.

THERE WILL BE AN INCREASED CHANCE FOR A PROTON EVENT AT
GEO-SYNCHRONOUS ORBIT BEGINNING ON 19 AUGUST.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEO-SYNCHRONOUS ALTITUDE IS
EXPECTED TO BE AT  NORMAL TO MODERATE LEVELS DURING MOST OF THE
PERIOD.

GEOMAGNETIC FIELD ACTIVITY IS EXPECTED TO BE AT QUIET TO UNSETTLED
LEVELS DURING THE PERIOD, BARRING ANY EARTH-DIRECTED CMES.


.