[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT44 KNHC 170245
TCDAT4
HURRICANE DANIELLE DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT MON AUG 16 2004

EARLIER THIS EVENING DANIELLE EXHIBITED A SMALL 10 NM WIDE EYE
COMPLETELY SURROUNDED BY COOLING CLOUD TOPS. SINCE THEN...CLOUD TOP
TEMPERATURES HAVE WARMED A BIT WITH THE STRONGEST CONVECTION NOW
OVER THE WESTERN SEMICIRCLE OF THE HURRICANE.  THE EYE IS NOW
ALMOST COMPLETELY OBSCURED...WHICH MAY BE A SIGN THAT DANIELLE IS
BEGINNING TO EXPERIENCE SOME SHEAR.  SATELLITE INTENSITY ESTIMATES
ARE CONSISTENT WITH THIS AS INDICATED BY SLIGHTLY LOWER T NUMBERS
FROM TAFB...SAB...AND AFWA.  THE INITIAL INTENSITY WILL BE HELD AT
90 KT FOR THE TIME BEING.

THE INITIAL MOTION IS 330/15...AND A DECELERATING TURN TO THE NORTH
IS EXPECTED AS DANIELLE ROUNDS THE WESTERN PERIPHERY OF A MID-LEVEL
RIDGE.  MOST OF THE GUIDANCE IS IN GOOD AGREEMENT THROUGH 48 HOURS.
AFTER THAT...THERE IS CONSIDERABLE DIVERGENCE IN THE MODEL
GUIDANCE.  THE GFS SHEARS OFF DANIELLE...ADVECTING THE MID/UPPER
LEVEL CIRCULATION TO THE NORTHEAST OF A WEAKENING LOW-LEVEL
CIRCULATION. THE OFFICIAL FORECAST ASSUMES THAT A VERTICALLY
COHERENT SYSTEM WILL PERSIST AND EVENTUALLY BE PICKED UP BY
STRONGER SOUTHWESTERLY FLOW AT DAYS 4 AND 5...FAVORING A TRACK
CLOSE TO THE MODEL CONSENSUS AND PREVIOUS OFFICIAL FORECAST.

INTENSITY GUIDANCE DISAGREES ON THE RATE OF WEAKENING...WITH SHIPS
BRINGING THE WINDS DOWN MUCH FASTER THAN THE GFDL.  THE SHEAR IS
FORECAST TO INCREASE ONLY MODESTLY OVER THE NEXT TWO DAYS...WHILE
SEA SURFACE TEMPERATURES WILL REMAIN RELATIVELY CONSTANT OR EVEN
INCREASE A LITTLE.  AS A RESULT...THE OFFICIAL FORECAST CALLS FOR
ONLY SLOW WEAKENING THROUGH 72 HOURS...AS INDICATED BY THE
GFDL...FOLLOWED BY THE MORE RAPID DECAY SHOWN BY THE SHIPS
GUIDANCE.

FORECASTER BERG/FRANKLIN

FORECAST POSITIONS AND MAX WINDS

INITIAL      17/0300Z 21.0N  39.2W    90 KT
 12HR VT     17/1200Z 22.8N  40.2W    85 KT
 24HR VT     18/0000Z 25.1N  41.0W    80 KT
 36HR VT     18/1200Z 27.5N  41.2W    75 KT
 48HR VT     19/0000Z 29.5N  41.0W    70 KT
 72HR VT     20/0000Z 33.0N  39.5W    65 KT
 96HR VT     21/0000Z 35.5N  35.5W    55 KT
120HR VT     22/0000Z 38.5N  29.5W    40 KT


$$
This weather bulletin was brought to you by:
www.nashvilleweather.net