000
WTPZ42 KNHC 090837
TCDEP2
TROPICAL STORM ESTELLE DISCUSSION NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP072010
200 AM PDT MON AUG 09 2010
 
ANOTHER STRONG BURST OF DEEP CONVECTION WITH CLOUD TOPS OF -75C TO
-85C HAS DEVELOPED DURING THE PAST 6 HOURS IN THE WESTERN
SEMICIRCLE OF THE LOW-LEVEL CIRCULATION. A BLEND OF SATELLITE
INTENSITY ESTIMATES FROM TAFB AND SAB AT 06Z SUPPORTS AN INTENSITY
OF 40 KT USING A SHEAR PATTERN...AND THE LATEST UW-CIMSS ADT
INTENSITY ESTIMATE IS 41 KT. THEREFORE...THE INTENSITY WILL REMAIN
AT 40 KT FOR THIS ADVISORY.  
 
ESTELLE HAS BEEN WOBBLING BETWEEN A WEST AND WEST-SOUTHWESTWARD
DIRECTION FOR THE PAST 12 HOURS...BUT THE BEST MOTION ESTIMATE FOR
THIS ADVISORY IS 270/4. ESTELLE IS EXPECTED TO TURN TO THE
SOUTHWESTWARD AND THEN SOUTHWARD OVER THE NEXT 48-72 HOURS AS THE
LOW-LEVEL AND UPPER-LEVEL CIRCULATIONS DECOUPLE DUE TO INCREASING
SOUTHEASTERLY VERTICAL WIND SHEAR. THE LOW-LEVEL CIRCULATION IS
THEN FORECAST BY MOST OF THE GLOBAL AND REGIONAL MODELS TO BE DRAWN
BACK INTO THE EASTERN PACIFIC MONSOON TROUGH AND POSSIBLY BE
ABSORBED INTO ANOTHER DISTURBANCE FORECAST TO DEVELOP OFF THE
SOUTHWESTERN COAST OF MEXICO. THE OFFICIAL FORECAST TRACK IS
SIMILAR TO THE PREVIOUS ADVISORY AND IS NEAR THE EASTERN EDGE OF
THE NHC MODEL GUIDANCE ENVELOPE.
 
WATER VAPOR IMAGERY INDICATES A SMALL REGION OF DRY STABLE AIR HAS
BEEN TRAVERSING THE CYCLONE...WHICH HAS LIKELY RESULTED IN THE
EARLIER EROSION OF THE CENTRAL CONVECTION. HOWEVER...TO THE EAST OF
THE CYCLONE IS AN APPARENT REGION OF INSTABILITY THAT CONTAINS DEEP
CONVECTION. AS THAT NARROW UNSTABLE REGION MOVES ACROSS ESTELLE...
NEW CONVECTION SHOULD DEVELOP IN THE EASTERN SEMICIRCLE...HELPING
THE CYCLONE TO MAINTAIN ITS CURRENT INTENSITY FOR ANOTHER 6 TO
PERHAPS 12 HOURS. AFTER THAT...HOWEVER...THE GLOBAL MODELS ARE
FORECASTING THE VERTICAL SHEAR TO INCREASE TO ABOVE 20 KT...WHICH
SHOULD INDUCE STEADY WEAKENING. THE SHIPS AND LGEM INTENSITY MODELS
DISSIPATE ESTELLE BY 72 HOURS...WHEREAS THE GFDL...HWRF...AND MOST
OF THE GLOBAL MODELS MAINTAIN ESTELLE AS A WEAK CYCLONE THROUGH AT
LEAST 96 HOURS. THE LATTER SCENARIO WAS USED FOR THIS ADVISORY.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/0900Z 17.7N 112.1W    40 KT
 12HR VT     09/1800Z 17.6N 112.8W    35 KT
 24HR VT     10/0600Z 17.5N 113.6W    30 KT
 36HR VT     10/1800Z 17.4N 114.0W    25 KT...POST-TROP/REMNT LOW
 48HR VT     11/0600Z 17.2N 114.1W    25 KT...POST-TROP/REMNT LOW
 72HR VT     12/0600Z 16.7N 113.6W    20 KT...POST-TROP/REMNT LOW
 96HR VT     13/0600Z 16.2N 112.5W    20 KT...POST-TROP/REMNT LOW
120HR VT     14/0600Z...DISSIPATED
 
$$
FORECASTER STEWART