000
WTPZ42 KNHC 070845
TCDEP2
TROPICAL STORM ESTELLE DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP072010
200 AM PDT SAT AUG 07 2010
 
THE STRUCTURE OF ESTELLE HAS CHANGED DURING THE LAST SEVERAL HOURS
AS A CENTRAL DENSE OVERCAST...WITH TOPS AS COLD AS -80C...HAS
DEVELOPED ALONG WITH A FEW CURVED BANDS MAINLY TO THE NORTH OF THE
CENTER. DVORAK CI-NUMBERS REMAIN 45 KT FROM BOTH TAFB AND SAB...AND
THE INITIAL INTENSITY WILL BE HELD AT THAT VALUE. A 0344 UTC TRMM
PASS AND A 0416 UTC AMSU PASS INDICATE THAT THE LOW-LEVEL CENTER OF
ESTELLE REFORMED ABOUT 50 MILES TO THE SOUTH OF THE PREVIOUSLY
ESTIMATED LOCATION. THIS REFORMATION CREATES A HIGHLY UNCERTAIN
INITIAL MOTION ESTIMATE OF 270/9. ESTELLE IS EXPECTED TO RESUME A
WEST-NORTHWESTWARD MOTION LATER TODAY AS THE CYCLONE IS STEERED BY
A MID-LEVEL RIDGE LOCATED TO ITS NORTHEAST. A SIGNIFICANT
DECELERATION IS FORECAST IN A COUPLE OF DAYS AS THE CYCLONE
APPROACHES A BREAK IN THE RIDGE AND BECOMES A SHALLOWER SYSTEM. THE
OFFICIAL FORECAST IS ADJUSTED SOUTHWARD TO ACCOUNT FOR THE INITIAL
LOCATION AND IS CLOSEST TO THE TVCN TRACK MODEL CONSENSUS.
 
SOME STRENGTHENING IS EXPECTED OVER THE NEXT 24 TO 36 HOURS AS
ESTELLE REMAINS IN A LOW VERTICAL WIND SHEAR ENVIRONMENT AND OVER
WARM WATERS. THE OFFICIAL FORECAST REMAINS NEAR THE HIGH END OF
THE MODEL GUIDANCE THROUGH 36 HOURS AND SHOWS A PEAK AT 60 KT.
BY 48 HOURS...THE CYCLONE IS FORECAST TO MOVE OVER SEA SURFACE
TEMPERATURES OF ABOUT 26C...AND STEADY WEAKENING IS EXPECTED TO
BEGIN AT THAT TIME.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      07/0900Z 16.8N 106.7W    45 KT
 12HR VT     07/1800Z 17.2N 108.0W    55 KT
 24HR VT     08/0600Z 17.6N 109.4W    60 KT
 36HR VT     08/1800Z 18.0N 110.5W    60 KT
 48HR VT     09/0600Z 18.3N 111.4W    55 KT
 72HR VT     10/0600Z 18.5N 112.5W    40 KT
 96HR VT     11/0600Z 18.5N 113.5W    30 KT
120HR VT     12/0600Z 18.5N 114.5W    20 KT...POST-TROP/REMNT LOW
 
$$
FORECASTER CANGIALOSI