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TROPICAL STORM LILI DISCUSSION NUMBER 17
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT WED SEP 25 2002
LILI REMAINS POORLY ORGANIZED AS INDICATED BY RECON WIND DATA THIS
MORNING. A WEAK CLOSED CIRCULATION WAS INDICATED IN THE WIND DATA
NEAR 13.7N 68.7W...BUT IT WAS NOT STRONG ENOUGH TO GENERATE A
VORTEX MESSAGE. 1500 FT FLIGHT-LEVEL WINDS OF 47 KT TO THE NORTHEAST
AND 45 KT TO THE EAST OF THE CENTER WERE ALSO REPORTED. DUE TO THE
UNCERTAINTY OF THE EXACT LOCATION OF THE CENTER OF THE BROAD
LOW-LEVEL CIRCULATION...I DID NOT WANT TO MAKE TOO MUCH OF A
SOUTHWARD RELOCATION SINCE A NEW CENTER COULD REFORM FARTHER NORTH
ALONG THE TROUGH AXIS NEAR THE STRONGER CONVECTION.
THE INITIAL MOTION REMAINS 285/10...EVEN THOUGH THE LOW-LEVEL CENTER
WAS RELOCATED A LITTLE MORE TO THE SOUTH OF THE PREVIOUS POSITIONS.
THE NHC TRACK GUIDANCE IS NOW SPLIT INTO TWO CAMPS WITH THE GLOBAL
MODELS AND THE GFDN MODEL TAKING LILI ACROSS EASTERN CUBA...WHILE
THE GFDL...THE BAM MODELS...AND THE AVN/GFS 10-MEMBER ENSEMBLE MEAN
MODEL TAKING THE CYCLONE BETWEEN JAMAICA AND SOUTHEAST CUBA. SINCE
THE GLOBAL MODELS HAVE CONTINUED THEIR WESTWARD SHIFT OVER THE PAST
3 DAYS...I HAVE SHIFTED THE OFFICIAL TRACK SLIGHTLY TO THE LEFT OR
WEST OF THE PREVIOUS FORECAST TRACK. UNCERTAINTY IN THE EXACT
LOCATION OF THE LOW-LEVEL CENTER PRECLUDES SHIFTING THE FORECAST
TRACK EVEN FARTHER TO THE LEFT AT THIS TIME.
AGAIN...DUE TO THE UNCERTAINTY IN THE LOCATION OF THE LOW-LEVEL
CENTER WITH RESPECT TO THE DEEP CONVECTION REQUIRES THAT THE
INTENSITY FORECAST REMAIN CONSERVATIVE AT THIS TIME. HOWEVER...THE
PRESENT SOUTHERLY UPPER-LEVEL SHEAR OF 15 TO 20 KT IS FORECAST TO
WEAKEN TO LESS THAN 10 KT BY 36 HOURS AND LESS THAN 5 KT BY 48 HOURS
ACCORDING TO THE SHIPS MODEL. THIS WOULD CERTAINLY SUGGEST THAT SOME
MODEST STRENGTHENING SHOULD OCCUR...ASSUMING WE STILL HAVE A
TROPICAL CYCLONE AT THAT TIME.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 25/1500Z 14.1N 69.3W 40 KTS
12HR VT 26/0000Z 14.7N 70.8W 40 KTS
24HR VT 26/1200Z 15.8N 72.5W 45 KTS
36HR VT 27/0000Z 17.1N 73.8W 50 KTS
48HR VT 27/1200Z 18.5N 74.9W 55 KTS
72HR VT 28/1200Z 21.5N 76.5W 55 KTS...NEAR EASTERN CUBA
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