Tropical Storm LESTER
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TROPICAL STORM LESTER DISCUSSION NUMBER 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT TUE OCT 12 2004
LESTER REMAINS A VERY SMALL BUT WELL-ORGANIZED TROPICAL STORM BASED
ON SURFACE AND RADAR DATA FROM ACAPULCO MEXICO...AND A 12/2248Z TRMM
OVERPASS. ALL THREE SATELLITE AGENCIES REPORTED A DVORAK INTENSITY
ESTIMATE OF T3.0...OR 45 KT. THEREFORE...THE INTENSITY IS INCREASED
TO 40 KT...BUT IS KEPT SLIGHTLY LOWER THAN THE SATELLITE ESTIMATES
DUE TO LAND INTERACTION AND A HIGHEST REPORTED SUSTAINED WIND OF
ONLY 21 KT AT ACAPULCO AT 12/2145Z.
THE INITIAL MOTION ESTIMATE IS 305/05. LESTER HAS REMAINED ON TRACK
AS IT MOVES SLOWLY AROUND THE SOUTHWEST PERIPHERY OF A WEAK MID- TO
UPPER-LEVEL RIDGE THAT LIES ALONG 22N LATITUDE...BASED ON 13/00Z
UPPER-AIR DATA. THE GLOBAL MODELS ARE IN GENERAL AGREEMENT ON THE
RIDGE REMAINING INTACT AND STRENGTHENING SLIGHTLY AFTER 24 HOURS.
THIS IS DUE TO A SHORTWAVE RIDGE BUILDING ACROSS WEST-CENTRAL
MEXICO AND BAJA CALIFORNIA BETWEEN TWO DEEP MID-LEVEL LOWS...ONE
WEST OF BAJA AND ONE OVER THE U.S. SOUTHERN PLAINS. THE MAIN
DIFFERENCE IN THE MODELS LIES IN THE LOCATION AND THE ORIENTATION
OF THE SHORTWAVE RIDGE. THE NOGAPS MODEL IS THE FARTHEST NORTH...
WHICH RESULTS IN LESTER REMAINING JUST OFFSHORE THE MEXICAN COAST...
WHILE THE OTHER MODELS ARE FARTHER SOUTH WITH THE RIDGE. THE
OFFICIAL FORECAST IS CLOSE TO THE MODEL CONSENSUS...MINUS THE GFS
MODEL WHICH QUICKLY DISSIPATES LESTER.
SINCE LESTER IS EXPECTED TO REMAIN A SMALLER THAN AVERAGE TROPICAL
CYCLONE...IT WILL BE SUSCEPTIBLE TO RAPID FLUCTUATIONS IN STRENGTH.
HOWEVER...THE OUTFLOW PATTERN IS ELONGATED NORTHEAST-SOUTHWEST...
WHICH WOULD NORMALLY SUGGEST THAT RAPID INTENSIFICATION WOULD BE
UNLIKELY. ALSO...A LARGE BURST OF DEEP CONVECTION ABOUT 140 NMI
SOUTHWEST OF THE LOW-LEVEL CENTER...COMBINED WITH LAND INTERACTION
TO THE NORTH...MAY SIGNIFICANTLY DISRUPT THE INFLOW. THEREFORE...
THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS FORECAST
AND IS SLIGHTLY LOWER THAN THE 00Z SHIPS INTENSITY MODEL.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 13/0300Z 16.5N 99.8W 40 KT
12HR VT 13/1200Z 16.8N 100.5W 45 KT
24HR VT 14/0000Z 17.0N 101.4W 50 KT
36HR VT 14/1200Z 17.0N 102.2W 55 KT
48HR VT 15/0000Z 17.0N 103.0W 65 KT
72HR VT 16/0000Z 17.0N 105.0W 65 KT
96HR VT 17/0000Z 17.5N 107.5W 65 KT
120HR VT 18/0000Z 18.5N 109.5W 65 KT
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