:Product: Weekly Highlights and Forecasts
:Issued: 2001 Sep 18 2112 UT
HIGHLIGHTS OF SOLAR AND GEOMAGNETIC ACTIVITY
10 - 16 SEPTEMBER 2001

SOLAR ACTIVITY RANGED FROM LOW TO HIGH LEVELS, BUT THE PREDOMINATE
CONDITION WAS MODERATE. ISOLATED, LOW-LEVEL M-CLASS FLARES OCCURRED
DURING MOST DAYS (FOR FLARE SPECIFICS, PLEASE REFER TO THE ENERGETIC
EVENTS AND FLARES LISTINGS). ACTIVITY ROSE TO HIGH LEVELS ON 16
SEPTEMBER WITH AN M5/2N FLARE FROM REGION 9608 (S27, L = 109,
CLASS/AREA FKC/1110 ON 10 SEPTEMBER) AT 16/0353 UTC. REGION 9608 WAS
ALSO RESPONSIBLE FOR AN M1/1N FLARE AT 15/1128 UTC ASSOCIATED WITH A
TYPE II RADIO SWEEP AND A PROTON EVENT (SEE THE DISCUSSION BELOW).
REGION 9608 GRADUALLY DECAYED, BUT REMAINED LARGE AND MAGNETICALLY
COMPLEX AS IT APPROACHED THE WEST LIMB AT THE CLOSE OF THE PERIOD. 
REGION 9616 (S11, L = 021, CLASS/AREA FSO/360 ON 14 SEPTEMBER) ALSO
PRODUCED ISOLATED LOW-LEVEL M-CLASS FLARES DURING THE PERIOD. THIS
REGION WAS MODERATE IN SIZE AND MAGNETIC COMPLEXITY. IT APPEARED TO
BE GRADUALLY DECAYING AS THE PERIOD ENDED. ANOTHER EVENT OF INTEREST
WAS A FILAMENT ERUPTION FROM THE NORTHEAST QUADRANT DURING 11/1346 -
1414 UTC ASSOCIATED WITH A HALO CME.

SOLAR WIND DATA WERE AVAILABLE FROM THE NASA ADVANCED COMPOSITION
EXPLORER (ACE) SPACECRAFT FOR MOST OF THE PERIOD. A WEAK HIGH-SPEED
STREAM ASSOCIATED WITH A CORONAL HOLE OCCURRED ON 11 - 12 SEPTEMBER
WITH PEAK VELOCITIES OF 500 KM/SEC. A CORONAL TRANSIENT PASSED EARTH
DURING 13 SEPTEMBER RESULTING IN RELATIVELY MINOR CHANGES IN THE
SOLAR WIND. ANOTHER CORONAL HOLE-RELATED HIGH SPEED STREAM WAS
OBSERVED DURING 15 - 16 SEPTEMBER WITH VELOCITIES AS HIGH AS 650
KM/SEC.

A BRIEF GREATER THAN 10 MEV PROTON EVENT OCCURRED AT GEOSYNCHRONOUS
ORBIT FOLLOWING AN M1 FLARE ON 15 SEPTEMBER. THE EVENT BEGAN AT
15/1435 UTC, REACHED A MAXIMUM OF 11 PFU AT 15/1455 UTC, AND ENDED
AT 15/1545 UTC. THE GREATER THAN 10 MEV FLUX RETURNED TO BACKGROUND
LEVELS THE NEXT DAY.

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

THE GEOMAGNETIC FIELD WAS DISTURBED DURING 11 - 12 SEPTEMBER DUE TO
CORONAL HOLE EFFECTS. ACTIVE LEVELS OCCURRED DURING THIS
DISTURBANCE. ACTIVE TO MINOR STORM PERIODS OCCURRED ON 13 SEPTEMBER
AS A CORONAL TRANSIENT PASSED EARTH. ACTIVE PERIODS ALSO OCCURRED
BEGINNING LATE ON 14 SEPTEMBER AND INTO 15 SEPTEMBER DUE TO CORONAL
HOLE EFFECTS. ACTIVITY DECLINED TO QUIET TO UNSETTLED LEVELS ON THE
LAST DAY OF THE PERIOD.

FORECAST OF SOLAR AND GEOMAGNETIC ACTIVITY
19 SEPTEMBER - 15 OCTOBER 2001

SOLAR ACTIVITY IS EXPECTED TO BE AT LOW TO MODERATE LEVELS. ISOLATED
M-CLASS FLARES ARE EXPECTED. THERE WILL BE A SLIGHT CHANCE FOR
ISOLATED MAJOR FLARE ACTIVITY DURING THE PERIOD.

THERE WILL BE A SLIGHT CHANCE FOR A SOLAR PROTON EVENT DURING THE
PERIOD.

THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT IS
EXPECTED TO BE AT NORMAL TO MODERATE LEVELS DURING MOST OF THE
PERIOD. HOWEVER, HIGH LEVELS WILL BE POSSIBLE AROUND 03 - 04
OCTOBER.

THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT ACTIVE LEVELS DURING 19 -
20 SEPTEMBER AND AGAIN DURING 30 SEPTEMBER - 01 OCTOBER. QUIET TO
UNSETTLED CONDITIONS ARE EXPECTED DURING THE REMAINDER OF THE
PERIOD.

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