Tropical Depression THIRTEEN-E

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TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION THIRTEEN-E DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 PM PDT FRI SEP 10 2004
 
THE AREA OF LOW PRESSURE SOUTH-SOUTHEAST OF THE GULF OF TEHUANTEPEC
HAS BEEN MAINTAINING ENOUGH DEEP CONVECTION AND BANDING NEAR THE
CENTER TO GENERATE DVORAK CLASSIFICATIONS OF T2.0 FROM BOTH TAFB
AND SAB.  ON THIS BASIS...ADVISORIES ARE INITIATED ON TROPICAL
DEPRESSION THIRTEEN-E.  ALTHOUGH THE CONVECTION IS RATHER THIN AT
THIS TIME IT IS WELL ORGANIZED.  SOME EASTERLY SHEAR IS APPARENT
FROM CIRRUS MOTIONS...BUT GLOBAL MODELS SUGGEST THAT IT SHOULD
REMAIN LOW ENOUGH TO ALLOW STRENGTHENING.  WATER TEMPERATURES ARE
VERY WARM...AND THE SHIPS GUIDANCE BRINGS THE DEPRESSION UP TO 80
KT IN 72 HOURS.  

THE INITIAL MOTION IS 285/15.  MODELS ARE ALL OVER THE PLACE IN
THEIR INITIALIZATION OF THE DEPRESSION...AND OFFER A CONFUSING
VARIETY OF POSSIBLE SOLUTIONS.  THE GFS TAKES THE DEPRESSION WEST
FOR A COUPLE OF DAYS...STALLS IT...THEN DRIFTS IT NORTH TOWARD THE
MEXICAN COAST.  THE UKMET STARTS OFF WITH A WEST-NORTHWESTERLY
TRACK AND THEN LOSES THE CYCLONE.  THE NOGAPS...WITH PERHAPS THE
POOREST INITIALIZATION...DRIFTS THE CYCLONE NORTHWARD OVER 4 DAYS
TO THE MEXICO/GUATEMALA BORDER.  THE CYCLONE APPEARS TO BE EMBEDDED
IN A DEEP EASTERLY CURRENT SOUTH OF A MID-LEVEL HIGH OVER NORTH-
CENTRAL MEXICO.  THE OFFICIAL FORECAST ASSUMES THAT THE BASIC
STEERING WILL BE PROVIDED BY THIS CURRENT AND IS IN BEST AGREEMENT
WITH THE BAM MODELS.  IT SHOWS A MOSTLY WEST-NORTHWEST TRACK WITH A
SHARP DECREASE IN FORWARD SPEED TO ACKNOWLEDGE THE CONSIDERABLE
UNCERTAINTY IN THE TRACK FORECAST.     
 
FORECASTER FRANKLIN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/2100Z 11.4N  94.1W    30 KT
 12HR VT     11/0600Z 12.2N  95.7W    40 KT
 24HR VT     11/1800Z 12.8N  97.9W    45 KT
 36HR VT     12/0600Z 13.0N  99.5W    50 KT
 48HR VT     12/1800Z 13.0N 101.0W    55 KT
 72HR VT     13/1800Z 13.0N 102.5W    65 KT
 96HR VT     14/1800Z 13.5N 104.0W    70 KT
120HR VT     15/1800Z 14.0N 105.5W    75 KT
 
 
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