Tropical Storm Lisa Weather Updates

[karl]

The next likely threat to Florida and the southeast U.S.

TROPICAL STORM LISA DISCUSSION NUMBER 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT MON SEP 20 2004

ALTHOUGH BANDING FEATURES HAVE CONTINUED TO IMPROVE...LISA STILL REMAINS A SMALL TROPICAL CYCLONE. THE BANDING EYE FEATURE OBSERVED EARLIER TODAY HAS DISSAPEARED UNDER A STRONG BURST OF DEEP CONVECTION OVER THE CENTER. THE INCREASED CONVECTIVE STRUCTURE... THE INCREASE IN THE CENTRAL DEEP CONVECTION...AND A 20/1547Z AQUA1 OVERPASS SHOWING A MID- AND LOW-LEVEL EYE FEATURE ARE MY REASONS FOR REMAINING HIGHER THAN THE DVORAK SATELLITE INTENSITY ESTIMATES OF 45 KT FROM BOTH TAFB AND SAB...AND 35 KT FROM AFWA.

THE INITIAL MOTION ESTIMATE IS 280/10. THERE REMAINS NO SIGNIFICANT CHANGE TO THE PREVIOUS TRACK FORECAST OR REASONING.

LISA IS EXPECTED TO CONTINUE MOVING IN A WEST TO WEST NORTHWESTWARD DIRECTION THROUGHOUT THE FORECAST PERIOD AS THE SMALL CYCLONE MOVES AROUND THE PERIPHERY OF A NARROW SUBTROPICAL RIDGE LOCATED BETWEEN LISA AND KARL. THE RIDGE IS FORECAST BY MOST OF THE MODELS TO REMAIN INTACT...DESPITE THE POOR INITIALIZATION OF THE CYCLONE BY ALL OF THE MODELS EXCEPT FOR NOGAPS. HOWEVER...THE NOGAPS MODEL APPEARS TO OVERDEVELOPMENT OF THE CYCLONE...WHICH ALLOWS IT TO ERODE THE NARROW RIDGE AND MOVE NORTHWESTWARD THROUGH IT. ON THE
OTHER HAND...THE GFDL...GFDN...AND DEEP BAM MODELS MOVE LISA WESTWARD FOR ABOUT 72 HOURS AND THEN SOUTHWESTWARD AS A RIDGE DEVELOPS TO THE NORTHWEST. UNTIL THE MODELS COME INTO MORE REASONABLE AGREEMENT...THE OFFICIAL FORECAST REMAINS CLOSE TO THE PREVIOUS FORECAST TRACKS AND FOLLOWS THE SYNOPTIC PATTERN OF ENOUGH RIDGING KEEPING THE VERY SMALL TROPICAL CYCLONE MOVING WESTWARD... WITH A GRADUAL DECREASE IN FORWARD SPEED AS THE RIDGE WEAKENS SOME.

COMPACT TROPICAL CYCLONES LIKE CAN STRENGTHEN FAIRLY QUICKLY...BUT CAN ALSO WEAKEN JUST AS FAST. THE VERTICAL SHEAR IS FORECAST TO REMAIN AROUND 10 KT OR LESS FOR THE NEXT 12 TO 18 HOURS...WHICH MAY ALLOW LISA TO STRENGTHEN INTO A HURRICANE LATER TONIGHT OR TUESDAY.

AFTERWARDS 36 HOURS...LOW TO MODERATE NORTHEAST TO EASTERLY VERTICAL SHEAR IS EXPECTED TO INHIBIT THE INTENSIFICATION INTENSIFICATION PROCESS...BUT NOT AS MUCH AS IF IT WAS WESTERLY
SHEAR. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS INTENSITY FORECAST...WHICH IS CONSISTENT WITH THE SHIPS MODEL... BUT MUCH HIGHER THAN THE GFDL MODEL.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL 20/2100Z 13.8N 36.8W 55 KT
12HR VT 21/0600Z 14.1N 38.2W 65 KT
24HR VT 21/1800Z 14.6N 39.9W 70 KT
36HR VT 22/0600Z 15.2N 41.6W 75 KT
48HR VT 22/1800Z 15.9N 43.2W 75 KT
72HR VT 23/1800Z 16.7N 46.0W 80 KT
96HR VT 24/1800Z 17.0N 49.0W 75 KT
120HR VT 25/1800Z 17.0N 52.0W 75 KT

5-Day Forecast Track

[LeslieM]

When will this madness end ????

[Photographer]

Sorry I'll try not to hit FL.

[kadiehl]

I thought my sister in law was Hurricane Lisa..OOPS bite my tongue