Tropical Storm ESTELLE

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TROPICAL STORM ESTELLE DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP072010
200 AM PDT SUN AUG 08 2010
 
CENTRAL DEEP CONVECTION HAS BEEN PULSING DURING THE PAST 6 HOURS
WITH CLOUD TOPS COOLING TO -82C AT TIMES. HOWEVER...THE OVERALL
TREND HAS BEEN A GRADUAL DECREASE IN AREAL COVERAGE OF THE CENTRAL
DENSE OVERCAST. THE CENTER HAS BEEN POSITIONED JUST NORTH
OF THE COLDEST OVERSHOOTING TOPS...WHICH IS CONSISTENT WITH A 0248Z
TRMM OVERPASS THAT REVEALED A COMPACT CYCLONE POSSESSING A
SMALL MID-LEVEL EYE-LIKE FEATURE. SATELLITE INTENSITY ESTIMATES
FROM TAFB AND SAB ARE T3.5/55 KT. ALTHOUGH BRIEF BURSTS OF
CONVECTION IN SUCH SMALL TROPICAL CYCLONES CAN RESULT IN A QUICK
SPIN-UP OF THE WIND FIELD...THE INTENSITY WILL REMAIN AT 55 KT FOR
THIS ADVISORY.
 
THE INITIAL MOTION ESTIMATE IS 290/09...SLIGHTLY FASTER AND NORTH OF
THE PREVIOUS POSITION AND TRACK BASED ON MICROWAVE FIXES. THERE IS
NO SIGNIFICANT CHANGE TO THE PREVIOUS TRACK FORECAST REASONING. THE
OFFICIAL TRACK FORECAST IS SLIGHTLY NORTH OR RIGHT OF THE PREVIOUS
TRACK...BUT ONLY DUE TO THE MORE NORTHWARD INITIAL POSITION. THE
WEAK SUBTROPICAL RIDGE TO THE NORTH OF ESTELLE SHOULD KEEP THE
CYCLONE MOVING ON A SLOW WESTWARD TRACK THROUGH 72 HOURS.  BEYOND 
THAT TIME THE CYCLONE IS EXPECTED TO WEAKEN OVER COOLER WATERS AND
TURN SOUTHWARD UNDER THE INFLUENCE OF THE LOW-LEVEL TRADE WIND
FLOW...AND COULD BE CAUGHT UP IN THE SOUTHWESTERLY LOW-LEVEL
MONSOONAL FLOW BY DAY 5. THE OFFICIAL FORECAST IS A BLEND OF THE
CONSENSUS MODEL...TVCN...AND THE PREVIOUS OFFICIAL FORECAST. 
 
SOME FLUCTUATIONS IN INTENSITY ARE POSSIBLE OVER THE NEXT 12 HOURS
AND ESTELLE COULD STILL REACH 60 KT INTENSITY. BY 24 HOURS...A
GRADUAL WEAKENING TREND IS EXPECTED TO ENSUE DUE TO A COMBINATION
OF INCREASING VERTICAL SHEAR AND SLIGHTLY COOLER SEA-SURFACE
TEMPERATURES AS FORECAST BY THE SHIPS AND LGEM INTENSITY MODELS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      08/0900Z 17.8N 110.3W    55 KT
 12HR VT     08/1800Z 17.9N 111.2W    55 KT
 24HR VT     09/0600Z 18.0N 112.3W    50 KT
 36HR VT     09/1800Z 18.0N 113.3W    45 KT
 48HR VT     10/0600Z 18.0N 114.2W    40 KT
 72HR VT     11/0600Z 17.9N 115.0W    30 KT
 96HR VT     12/0600Z 17.2N 115.2W    20 KT...POST-TROP/REMNT LOW
120HR VT     13/0600Z 16.4N 114.7W    20 KT...POST-TROP/REMNT LOW
 
$$
FORECASTER STEWART
 
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