[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 252035
TCDAT3
TROPICAL STORM LISA DISCUSSION NUMBER  26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT SAT SEP 25 2004

LISA AS BEEN WOBBLING AROUND AN ESTIMATED TRACK OF 335/9 KT.  THE
EXACT MOTION HAS BEEN SOMEWHAT DIFFICULT TO DETERMINE AS SEVERAL
SMALL CLOUD SWIRLS HAVE BEEN ROTATING AROUND A MEAN CENTER.  THE
CONVECTIVE BAND ON THE EAST SIDE HAS WRAPPED CLOSER TO THE CENTER
DURING THE DAY.  HOWEVER...CURRENT DVORAK INTENSITY ESTIMATES
REMAIN 35 KT FROM ALL AGENCIES AND LISA WILL REMAIN A 35 KT
TROPICAL STORM ON THIS ADVISORY.

DYNAMICAL MODELS ARE IN FAIRLY GOOD AGREEMENT WITH LISA TRACKING
NORTH-NORTHWEST TOWARD A BREAK IN THE SUBTROPICAL RIDGE OVER THE
CENTRAL ATLANTIC. LATE IN THE FORECAST PERIOD...THERE ARE
DIFFERENCES IN THE MODELS AS A MID-LEVEL RIDGE IS FORECAST TO BUILD
EASTWARD ACROSS THE CENTRAL ATLANTIC. THE NOGAPS AND UKMET WHICH
START OUT WITH A SLOWER NORTHWEST MOTION TURN LISA WEST-NORTHWEST
NEAR THE END OF THE FORECAST PERIOD AS THE RIDGE BUILDS.
HOWEVER...THE GFS AND GFDL WHICH HAVE A FASTER MOTION DO NOT SHOW
AS SHARP A TURN. THE OFFICIAL FORECAST IS ADJUSTED A LITTLE TO THE
RIGHT AND DOES NOT LEAN TOWARD ONE SOLUTION OR THE OTHER...BUT
REMAINS VERY CLOSE TO THE CONSENSUS OF THE GLOBAL MODELS.

THE INTENSITY FORECAST CALLS FOR SLOW STRENGTHENING THROUGH
72 HOURS...THEN LEVELS LISA OFF JUST BELOW HURRICANE STRENGTH.
THIS FOLLOWS THE SHIPS MODEL CLOSELY THROUGH 72 HOURS...THEN
IS A LITTLE MORE CONSERVATIVE AT THE END OF THE FORECAST PERIOD.

FORECASTER BROWN/AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL      25/2100Z 17.2N  45.8W    35 KT
 12HR VT     26/0600Z 18.3N  46.4W    40 KT
 24HR VT     26/1800Z 19.8N  47.1W    45 KT
 36HR VT     27/0600Z 21.4N  47.9W    50 KT
 48HR VT     27/1800Z 23.2N  48.7W    55 KT
 72HR VT     28/1800Z 25.5N  50.0W    60 KT
 96HR VT     29/1800Z 28.0N  51.0W    60 KT
120HR VT     30/1800Z 30.0N  52.0W    60 KT


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