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TROPICAL STORM JULIETTE DISCUSSION NUMBER   4
NATIONAL WEATHER SERVICE MIAMI FL
2 AM PDT SAT SEP 22 2001
 
DURING THE PAST 6 HOURS...THERE HAS BEEN A SIGNIFICANT SOUTHWARD 
SHIFT IN THE CENTER OF JULIETTE ALONG WITH A MARKED DECREASE IN THE 
CENTRAL DEEP CONVECTION.  THE STRONGEST CONVECTION IS DISPLACED WELL 
TO THE WEST AND NORTHWEST OF THE CENTER.  HOWEVER...A TIGHT CURL OF 
MODERATE CONVECTION REMAINS COILED AROUND THE APPARENT CENTER OF 
CIRCULATION.  OUTFLOW IS GOOD TO THE NORTHWEST AND FAIR ELSEWHERE.
 
THE INITIAL MOTION ESTIMATE IS 270/17.  THE SOUTHWESTWARD SHIFT IN
THE CENTER AND EROSION OF THE CENTRAL DEEP CONVECTION MAY HAVE BEEN
DUE TO DOWNSLOPE FLOW FROM THE ISTHMUS OF TEHUANTAPEC.  HOWEVER...
CONVECTION HAS REDEVELOPED AROUND THE CENTER OF CIRCULATION DURING
THE PAST COUPLE OF HOURS...SO A GENERAL WEST OR WEST-NORTHWESTWARD
TRACK IS EXPECTED TO RESUME SHORTLY.  MOST OF THE NHC MODEL GUIDANCE
IS IN GENERAL AGREEMENT ON TAKING JULIETTE WEST-NORTHWESTWARD
THROUGH 36 HOURS WITH A GRADUAL TURN TOWARD THE NORTHWEST OR NORTH
AFTER THAT.  THIS IS CONSISTENT WITH A DEEP TROUGH FORECAST TO DIG
SOUTH AND SOUTHWESTWARD ACROSS THE SOUTHEAST U.S.  AND THE SOUTHERN
PLAINS AND INTO NORTHERN MEXICO.  THE RESULT IS AN EXPECTED EROSION
OF THE MID-LEVEL RIDGE CURRENTLY ACROSS MEXICO AND BAJA
CALIFORNIA...WHICH SHOULD ALLOW THE CYCLONE TO GRADUALLY MOVE MORE
POLEWARD IN THE LATTER FORECAST PERIODS.  THE OFFICIAL FORECATS
TRCAK IS CLOSE TO THE PREVIOUS TRACK AFTER 12 HOURS...AND IS BETWEEN
THE AVN AND UKMET MODELS.

GRADUAL STRENGTHENING IS EXPECTED AFTER ABOUT 12 HOURS WHEN JULIETTE 
IS EXPECTED TO MOVE AWAY FROM THE EFFECTS OF THE MEXICAN COASTAL 
MOUNTAINS.  THE SHIPS INTENSITY FORECAST MODEL WAS CLOSELY FOLLOWED
...WHICH IS NOT QUITE AS ROBUST AS THE GFDL MODEL WHICH TAKES THE 
CYCLONE UP TO 113 KT IN 48 HOURS.  THE GFDL SEEMS TO BE OVERDOING 
THE INTENSITY FORECAST GIVEN THE CLOSE PROXIMITY TO LAND.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     22/0900Z 13.6N  98.4W    50 KTS
12HR VT     22/1800Z 13.7N  99.5W    55 KTS
24HR VT     23/0600Z 14.2N 101.3W    65 KTS
36HR VT     23/1800Z 15.0N 102.8W    75 KTS
48HR VT     24/0600Z 16.0N 104.2W    85 KTS
72HR VT     25/0600Z 18.0N 106.0W    95 KTS
 
 
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