:Product: Weekly Highlights and Forecasts
:Issued: 2000 Apr 25 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
17 - 23 APRIL 2000

SOLAR ACTIVITY WAS LOW. C-CLASS FLARES OCCURRED DAILY. THE WEEK'S
PRINCIPAL FLARE PRODUCER WAS REGION 8963 (N16, L = 002, CLASS/AREA
DAO/080 ON 18 APRIL), A RELATIVELY SMALL, MIXED-POLARITY REGION.
THIS REGION SHOWED MINOR GROWTH THROUGH 20 APRIL, THEN SLOWLY
DECAYED. ONE EVENT OF NOTE FROM REGION 8963 WAS A C4 X-RAY FLARE AT
18/1153UT WITH AN ASSOCIATED TYPE II RADIO SWEEP.

REAL-TIME SOLAR WIND DATA WERE AVAILABLE FROM THE NASA ADVANCED
COMPOSITION EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD. EARTH
WAS WITHIN A POSITIVE-POLARITY (AWAY) SOLAR SECTOR MOST OF THE
PERIOD. IMF BZ VARIED BETWEEN PLUS TO MINUS 05 NT (GSM) DURING MOST
OF THE PERIOD, BUT BECAME MORE VARIABLE DURING 19 APRIL WITH A RANGE
OF PLUS 09 TO MINUS 11 NT. VELOCITIES INCREASED DURING 19 - 21
APRIL, POSSIBLY DUE TO WEAK CORONAL HOLE EFFECTS, WITH PEAKS TO 580
KM/SEC. DENSITIES WERE ENHANCED ON 19 APRIL WITH PEAK READINGS TO 18
P/CC.

THE GREATER THAN 10 MEV PROTON FLUX BECAME ENHANCED AROUND 23/1500UT
AND REMAINED SO THROUGH THE END OF THE PERIOD. THIS ENHANCEMENT MAY
HAVE BEEN ASSOCIATED WITH AN EVENT BEYOND THE WEST LIMB NEAR MIDDAY
ON 23 APRIL.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT WAS AT
NORMAL LEVELS THROUGHOUT THE PERIOD.

GEOMAGNETIC FIELD ACTIVITY WAS AT QUIET TO ACTIVE LEVELS DURING MOST
OF THE PERIOD. HOWEVER, THE ACTIVE PERIODS WERE MOSTLY ISOLATED.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
26 APRIL - 22 MAY 2000

SOLAR ACTIVITY IS EXPECTED TO VARY BETWEEN LOW AND MODERATE LEVELS
WITH ISOLATED LOW-LEVEL M-CLASS FLARES POSSIBLE.

NO PROTON EVENTS ARE EXPECTED AT GEOSYNCHRONOUS ORBIT.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS
EXPECTED TO BE AT NORMAL TO MODERATE LEVELS DURING MOST OF THE
PERIOD.

GEOMAGNETIC FIELD ACTIVITY IS EXPECTED TO BE AT MOSTLY QUIET TO
UNSETTLED LEVELS, BARRING AN EARTH-DIRECTED CME.


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