000
WTPZ43 KNHC 041433
TCDEP3
TROPICAL STORM POLO DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP182008
700 AM PST TUE NOV 04 2008
 
DEEP CONVECTION HAS CONTINUED TO INCREASE NEAR THE CENTER OF POLO
OVER THE PAST FEW HOURS.  ANALYSES FROM CIMSS AT THE
UNIVERSITY OF WISCONSIN AND THE SHIPS MODEL INDICATE THAT
WEST-NORTHWESTERLY SHEAR CONTINUES OVER THE CYCLONE...AND WE
ESTIMATE THAT THE CENTER IS LOCATED NEAR THE WESTERN EDGE OF THE
DEEP CONVECTION.  DVORAK T-NUMBERS FROM TAFB AND SAB AT 1200 UTC
WERE 3.0 AND 2.5 RESPECTIVELY.  GIVEN THE SHEAR AND THE ESTIMATED
DISPLACEMENT OF THE CENTER RELATIVE TO THE DEEP CONVECTION...WE
HAVE HELD THE INITIAL INTENSITY AT 35 KT.
 
THE INITIAL MOTION ESTIMATE IS 285/10.  THERE IS LITTLE CHANGE TO
THE TRACK FORECAST REASONING.  THE NEW TRACK FORECAST IS CLOSE TO
THE PREVIOUS TRACK AND IS SHIFTED TOWARD THE NEW GLOBAL MODEL
CONSENSUS...DISCOUNTING THE GFDL AND HWRF THAT CONTINUE TO BE RIGHT
OUTLIERS.
 
GIVEN THE RECENT IMPROVEMENT IN THE CONVECTIVE APPEARANCE...THE 12
HOUR INTENSITY FORECAST WAS INCREASED TO 40 KT...AND HELD THERE
THROUGH 48 HOURS.  BEYOND THAT TIME...THE SHIPS MODEL SHOWS
SHEAR VALUES INCREASING TO AROUND 40 KT AFTER 72 HOURS...AND THE
CYCLONE WILL BE MOVING OVER COOLER SEA SURFACE TEMPERATURES.
THEREFORE...WEAKENING IS INDICATED BY DAY 3 AND BEYOND...IN CLOSEST
AGREEMENT WITH THE LGEM.  THE CYCLONE IS FORECAST TO BECOME A
REMNANT LOW BY DAY 5...HOWEVER GIVEN THE SMALL SIZE OF POLO...IT
COULD WEAKEN MORE QUICKLY THAN FORECAST ONCE IT ENCOUNTERS THE
STRONGER VERTICAL WIND SHEAR.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      04/1500Z  9.9N 117.6W    35 KT
 12HR VT     05/0000Z 10.3N 119.0W    40 KT
 24HR VT     05/1200Z 10.9N 120.8W    40 KT
 36HR VT     06/0000Z 11.6N 122.5W    40 KT
 48HR VT     06/1200Z 12.0N 124.1W    40 KT
 72HR VT     07/1200Z 12.5N 127.5W    35 KT
 96HR VT     08/1200Z 13.0N 130.5W    30 KT
120HR VT     09/1200Z 13.5N 134.0W    25 KT...REMNANT LOW
 
$$
FORECASTER BRENNAN/PASCH