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TROPICAL DEPRESSION NINE-E DISCUSSION NUMBER   1
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT SUN AUG 25 2002
 
VISIBLE AND INFRARED SATELLITE IMAGERY INDICATE THE TROPICAL 
DISTURBANCE LOCATED ABOUT 475 MILES SOUTHWEST OF MANZANILLO MEXICO 
HAS STRENGTHENED INTO TROPICAL DEPRESSION NINE-E.  BANDING FEATURES 
HAVE IMPROVED SIGNIFICANTLY DURING THE PAST 6 HOURS AND THE INITIAL 
INTENSITY OF 30 KT IS BASED ON A DVORAK SATELLITE INTENSITY ESTIMATE 
OF T2.0...OR 30 KT...FROM TAFB. UPPER-LEVEL OUTFLOW IS FAIR IN ALL 
QUADRANTS...BUT IS STEADILY IMPROVING.

THE INITIAL MOTION ESTIMATE IS 270/05.  THE TROPICAL CYCLONE IS 
EXPECTED TO REMAIN SOUTH OF THE SUBTROPICAL RIDGE THAT EXTENDS FROM 
NORTHERN MEXICO WESTWARD TO NORTH OF HURRICANE FAUSTO. ALL OF THE 
GLOBAL MODELS POORLY INITIALIZED THIS SYSTEM...AT BEST...DESPITE THE 
WELL-DEFINED LOW-LEVEL CIRCULATION DEPICTED NICELY IN AN EARLIER 
QUIKSCAT OVERPASS. AS SUCH...THE OFFICIAL FORECAST TRACK IS A BLEND 
OF THE CLIPER... LBAR...DEEP AND MEDIUM BAM MODELS...AND ALSO USING 
THE OVERALL SYNOPTIC PATTERN FOR A "STRAIGHT-RUNNER.".  

THE SHIPS INTENSITY MODEL WAS FOLLOWED CLOSELY THRU 36 HOURS AND 
THEN THE INTENSITY WAS INCREASED ABOVE SHIPS AFTER THAT. THE REASON 
IS THAT THE SHIPS MODEL USED THE LBAR FORECAST TRACK TO DETERMINE 
THE VERTICAL SHEAR...WHICH REMAINS LESS THAN 10 KT THRU 48 
HOURS...BUT THEN INCREASES THE SHEAR SIGNIFICANTLY SINCE LBAR TAKES 
THE CYCLONE RAPIDLY NORTHWESTWARD AFTER 48 HOURS. THE AVN MODEL IS 
FORECASTING AN UPPER-LEVEL LOW IN THE VICINITY OF THE OFFICIAL 48- 
AND 72-HOUR POSITIONS. HOWEVER...NOGAPS AND THE UKMET MODELS MOVE 
THE UPPER-LEVEL LOW FASTER TO THE WEST AND KEEP THE CYCLONE UNDER 
WEAK ANTICYCLONIC FLOW.  GIVEN THE POOR INITIALIZATION OF THIS 
SYSTEM BY THE AVN AND CURRENT WATER VAPOR IMAGERY INDICATING ONE 
UPPER-LEVEL LOW SOUTH OF BAJA CALIFORNIA MOVING WESTWARD AND ANOTHER 
ONE SOUTHWEST OF THE DEPRESSION DROPPING SOUTHWESTWARD...THEN IT 
APPEARS THAT THE NOGAPS AND UKMET MODELS HAVE A BETTER HANDLE ON THE 
UPPER-LEVEL FLOW PATTERN. HOWEVER...SINCE THE DEPRESSION IS EXPECTED 
TO PASS BETWEEN THE TWO UPPER-LOWS...THE OUFLOW ENVIRONMENT APPEARS 
TO BE CONDUCIVE FOR SIGNIFICANT INTENSIFICATION ONCE THE INNER-CORE 
CONVECTION PERSISTS...AND THE OFFICIAL INTENSITY FORECAST COULD BE 
TOO LOW AT 48- AND 72-HOURS.
 
FORECASTER STEWART
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     26/0300Z 15.0N 110.3W    30 KTS
12HR VT     26/1200Z 15.1N 111.3W    35 KTS
24HR VT     27/0000Z 15.3N 112.7W    45 KTS
36HR VT     27/1200Z 15.5N 114.2W    55 KTS
48HR VT     28/0000Z 15.8N 115.9W    70 KTS
72HR VT     29/0000Z 16.5N 119.0W    80 KTS
 
 
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