Tropical Storm ERNESTO

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TROPICAL STORM ERNESTO DISCUSSION NUMBER   6...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052006
1100 PM EDT FRI AUG 25 2006

...CORRECTED TO INDICATE NEAR JAMAICA AT 36 HOURS...
 
SINCE THE RECONNAISSANCE AIRCRAFT DEPARTED FROM THE TROPICAL
STORM...CONVECTION HAS DEEPENED AND EXPANDED...BUT IS STILL
DISPLACED MOSTLY EAST OF THE LOW-LEVEL CENTER.  THE UW-CIMSS SHEAR
ANALYSES ESTIMATE ABOUT 15 KTS OF WESTERLY SHEAR CURRENTLY
AFFECTING ERNESTO WITH STRONGER SHEAR TO THE NORTHWEST.  IT HAS
BEEN A BIT DIFFICULT TO DETERMINE THE LOW-LEVEL CENTER LOCATION AND
CONSEQUENTLY THE INITIAL INTENSITY BASED UPON THE DVORAK SHEAR
PATTERN.  DUE TO THE DEEPENING CONVECTION AND DATA T-NUMBERS FROM
TAFB AND SAB RANGING FROM 35 KT TO 45 KT...THE INITIAL INTENSITY
HAS BEEN BUMPED UP TO 40 KT. RECONNAISSANCE AIRCRAFT WILL BE BACK
IN TO INVESTIGATE ERNESTO AT 0600 UTC TO GET A BETTER HANDLE ON THE
CURRENT POSITION AND INTENSITY.

THE INITIAL MOTION IS 285/14.  A LOW- TO MID-LEVEL RIDGE ACROSS THE
SOUTHWEST ATLANTIC CONTINUES TO STEER ERNESTO ON A WEST-NORTHWEST
TRACK AND SHOULD CONTINUE TO DO SO FOR THE NEXT 48 TO 72 HOURS...AND
THE MODELS ARE IN TIGHT AGREEMENT DURING THIS PERIOD.  THE TRACK
FORECAST BECOMES A BIT TRICKY ON DAYS 4 AND 5...WHEN A WEAKNESS IN
THE STEERING PATTERN DEVELOPS ACROSS THE CENTRAL GULF OF MEXICO
FORECAST BY MOST OF THE MODELS.  THE OFFICIAL TRACK FORECAST KEEPS
ERNESTO ON A GENERAL NORTHWESTWARD TRACK OVER THE GULF OF MEXICO.   

CURRENTLY AN UPPER-LEVEL LOW IS SITUATED OVER EASTERN CUBA AND
JAMAICA WITH STRONG WEST-SOUTHWESTERLY WINDS TO ITS SOUTHEAST.
WATER VAPOR IMAGERY INDICATES THIS UPPER-LEVEL LOW IS MOVING RAPIDLY
TO THE WEST-SOUTHWEST...AND THE MODELS ARE IN CLOSE AGREEMENT THAT
THE LOW SHOULD END UP ALONG THE EASTERN COAST OF MAINLAND MEXICO IN
3 TO 4 DAYS.  THIS SCENARIO SHOULD PROVIDE A VERY WEAK SHEAR
ENVIRONMENT FOR ERNESTO TO STRENGTHEN...AND IN FACT THE SHIPS
GUIDANCE FORECASTS THE SHEAR TO WEAKEN CONSIDERABLY IN 36-48 HOURS
AND REMAIN WEAK THROUGH DAY 5.  THE OFFICIAL INTENSITY FORECAST
OVER THE GULF OF MEXICO IS NUDGED UPWARD...SINCE MOST OF THE
INTENSITY GUIDANCE INDICATES AN EVEN STRONGER INTENSITY THAN SHOWN
BELOW.   
 
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      26/0300Z 14.8N  69.1W    40 KT
 12HR VT     26/1200Z 15.6N  71.1W    45 KT
 24HR VT     27/0000Z 16.6N  73.7W    50 KT
 36HR VT     27/1200Z 17.8N  76.4W    55 KT...NEAR JAMAICA
 48HR VT     28/0000Z 19.0N  79.0W    60 KT
 72HR VT     29/0000Z 22.0N  84.0W    70 KT
 96HR VT     30/0000Z 24.0N  87.0W    80 KT
120HR VT     31/0000Z 26.0N  90.0W    85 KT
 
$$
FORECASTER MAINELLI/KNABB
 
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