[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 271457
TCDAT3
TROPICAL STORM LISA DISCUSSION NUMBER  33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT MON SEP 27 2004

METEOSAT-8 AND GOES-12 VISIBLE IMAGERY SHOW LISA REMAINS AS A
SHEARED SYSTEM WITH AN EXPOSED CENTER. THE CONVECTION IN THE
NORTHEAST QUADRANT CONTINUES TO PULSATE THROUGHOUT THE MORNING. THE
INITIAL INTENSITY IS 40 KTS BASED ON TAFB AND SAB DVORAK CI NUMBERS
OF 3.0 AND 2.5.

THE INITIAL MOTION IS 340/5. LISA IS CURRENTLY LOCATED SOUTHWEST OF
A MID-LEVEL RIDGE. IN THE SHORT TERM...MODELS SUGGEST THAT LISA
WILL CONTINUE TO BE STEERED BY THIS MID-LEVEL RIDGE AND IT WILL
KEEP LISA ON A MORE NORTH-NORTHWEST TRACK. HOWEVER...THE MODELS
DIVERGE IN THE LATER FORECAST PERIOD WITH THE NOGAPS AND GFDN
CONTINUING MOVEMENT TOWARD THE NORTHWEST WHILE THE OTHER GUIDANCE
STEERS THE SYSTEM TO THE NORTHEAST. THE OFFICIAL FORECAST TENDS
TOWARD CONU AND GUNS MODEL CONSENSUS BUT SLOWS THE MOTION AT THE
LONGER TIME PERIOD.

LITTLE CHANGE IN INTENSITY IS FORECAST AS STRONG-TO-MODERATE SHEAR
REMAINS OVER THE SYSTEM FOR THE NEXT 36 HOURS. BEYOND 36 HOURS...
THE SHEAR LOWERS AND ALLOWS LISA TO SLOWLY STRENGTHEN. THE NHC
INTENSITY FORECAST HOLDS THE INTENSITY FOR 48 HOURS AND THEN
STRENGTHENING TO HURRICANE FORCE IS FORECAST IN THE LATER TIME
PERIOD. IF LISA CAN MAINTAIN ITSELF IN THE PRESENCE OF THE CURRENT
SHEAR FOR THE NEXT COUPLE OF DAYS...THERE IS AN OPPORTUNITY FOR
LISA TO BECOME A HURRICANE AS THE SYSTEM REMAINS IN A LOW SHEAR
ENVIRONMENT AND WARM SST REGIME.

FORECASTER SISKO/PASCH

FORECAST POSITIONS AND MAX WINDS

INITIAL      27/1500Z 20.8N  46.5W    40 KT
 12HR VT     28/0000Z 21.8N  47.0W    40 KT
 24HR VT     28/1200Z 23.2N  47.7W    40 KT
 36HR VT     29/0000Z 24.6N  48.5W    40 KT
 48HR VT     29/1200Z 26.0N  48.9W    45 KT
 72HR VT     30/1200Z 29.0N  49.8W    55 KT
 96HR VT     01/1200Z 31.0N  50.5W    65 KT
120HR VT     02/1200Z 33.0N  51.0W    65 KT


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