Tropical Storm ALETTA

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TROPICAL STORM ALETTA DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP012006
800 PM PDT SAT MAY 27 2006

THE FIRST STORM OF THE SEASON IS LOOKING LIKE A TOUGH ONE TO
FORECAST.  LAST-LIGHT VISIBLE IMAGES DEPICTED A LOW-LEVEL
CIRCULATION CENTER MOVING WESTWARD...AWAY FROM THE DEEP CONVECTION. 
SSM/I AND AMSR-E IMAGES ALSO SHOWED A LOW-LEVEL CENTER DISPLACED TO
THE WEST OF THE CONVECTION.  UNLESS A NEW CENTER DEVELOPS FARTHER TO
THE EAST... ALETTA MAY NOT LAST VERY LONG.  GIVEN THAT THE CENTER
HAS REFORMED NEAR THE DEEP CONVECTION AT LEAST TWICE ALREADY IN THIS
SYSTEM...IT MIGHT NOT BE UNREASONABLE TO EXPECT YET ANOTHER
REFORMATION.  DVORAK CURRENT INTENSITY ESTIMATES RANGE FROM 35 TO 45
KT.  SINCE THE SYSTEM IS NOT WELL ORGANIZED AT THIS TIME...THE
INITIAL WIND SPEED IS HELD AT 35 KT FOR THIS PACKAGE.  IN SPITE OF
THE CURRENTLY DISORGANIZED STATE OF THE TROPICAL CYCLONE...THE
GLOBAL MODELS ARE FORECASTING A MORE FAVORABLE UPPER- TROPOSPHERIC
ENVIRONMENT OF WEAKER SHEAR AND ANTICYCLONIC FLOW TO DEVELOP OVER
THE NEXT DAY OR TWO.  THEREFORE...I WILL CONTINUE TO FORECAST SOME
INTENSIFICATION...AS IN THE PREVIOUS ADVISORIES.  THIS IS ALSO IN
GENERAL AGREEMENT WITH THE SHIPS INTENSITY FORECAST.

THERE HAS BEEN LITTLE OVERALL MOTION OVER THE PAST SEVERAL HOURS...
AND STEERING CURRENTS ARE LIKELY TO REMAIN RATHER WEAK FOR THE NEXT
FEW DAYS.  THERE ARE NOW NO DYNAMICAL MODELS THAT TAKE THE TROPICAL
CYCLONE WESTWARD.  THE GFDL AND NOGAPS MODELS FORECAST ALETTA TO
MOVE INLAND OVER SOUTHERN MEXICO WITHIN 24-36 HOURS.  IT SHOULD BE
NOTED THAT THE GFDL'S VORTEX TRACKER...WHICH IS LISTED ON THE
STANDARD OUTPUT MESSAGE...LOSES TRACK OF THE SYSTEM AND DOES NOT
INDICATE LANDFALL.  HOWEVER...INSPECTION OF THE GFDL MODEL OUTPUT
FIELDS OF SEA LEVEL PRESSURE CLEARLY SHOWS THE CENTER CROSSING THE
COAST.  SINCE THERE IS CURRENTLY NO CREDIBLE GUIDANCE TO FORECAST A
WESTWARD MOTION LATER IN THE PERIOD...THE OFFICIAL FORECAST TRACK IS
SHIFTED EASTWARD FROM THE PREVIOUS ADVISORY...AND KEEPS THE SYSTEM
STATIONARY FROM DAYS 3-5.  OBVIOUSLY...ALETTA MAY HAVE MOVED INLAND
AND DISSIPATED BY THEN.  
 
FORECASTER PASCH
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      28/0300Z 15.7N 101.0W    35 KT
 12HR VT     28/1200Z 16.0N 100.9W    40 KT
 24HR VT     29/0000Z 16.3N 100.8W    45 KT
 36HR VT     29/1200Z 16.6N 100.7W    50 KT
 48HR VT     30/0000Z 16.9N 100.7W    50 KT
 72HR VT     31/0000Z 17.0N 101.0W    55 KT
 96HR VT     01/0000Z 17.0N 101.0W    55 KT
120HR VT     02/0000Z 17.0N 101.0W    55 KT
 
 
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