Sunday, September 02, 2012

Tropical storm Leslie a potential long range threat to the region










000
WTNT32 KNHC 030239
TCPAT2

BULLETIN
TROPICAL STORM LESLIE ADVISORY NUMBER  15
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122012
1100 PM AST SUN SEP 02 2012

...LESLIE SHOWING LITTLE CHANGE IN STRENGTH...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.4N 61.7W
ABOUT 435 MI...700 KM N OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 PM AST...0300 UTC...THE CENTER OF TROPICAL STORM LESLIE WAS
LOCATED NEAR LATITUDE 23.4 NORTH...LONGITUDE 61.7 WEST. LESLIE IS
MOVING TOWARD THE NORTHWEST NEAR 10 MPH...17 KM/H.. A TURN TOWARD
THE NORTH-NORTHWEST AND THEN THE NORTH AT A SLOWER FORWARD SPEED IS
EXPECTED OVER THE NEXT 48 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 60 MPH...95 KM/H...WITH HIGHER
GUSTS.  LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT COUPLE
OF DAYS.

TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 205 MILES...335 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB...29.47 INCHES.


HAZARDS AFFECTING LAND
----------------------
SURF...SWELLS GENERATED BY LESLIE COULD AFFECT PORTIONS OF THE
LEEWARD ISLANDS FOR THE NEXT DAY OR SO...AND ARE BEGINNING TO AFFECT
PUERTO RICO AND THE VIRGIN ISLANDS.  THESE SWELLS COULD CAUSE
LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS.  PLEASE CONSULT
PRODUCTS FROM YOUR LOCAL WEATHER OFFICE.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 AM AST.

$$
FORECASTER PASCH

000 WTNT42 KNHC 030240 TCDAT2 TROPICAL STORM LESLIE DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012 1100 PM AST SUN SEP 02 2012 LESLIE CONTINUES TO BE UNDER THE INFLUENCE OF STRONG NORTHWESTERLY SHEAR. ALTHOUGH THE CLOUD TOPS ARE QUITE COLD...SUGGESTING VIGOROUS DEEP CONVECTION...THERE IS LITTLE EVIDENCE OF BANDING FEATURES AS THE CLOUD PATTERN HAS THE APPEARANCE OF AN AMORPHOUS BLOB. SINCE THERE HAVE BEEN NO NOTABLE CHANGES IN THE APPEARANCE OF THE SYSTEM OVER THE PAST SEVERAL HOURS...THE INTENSITY ESTIMATE IS HELD AT 50 KT FOR THIS ADVISORY. THE SHEAR IS EXPECTED TO REMAIN PROHIBITIVE FOR SIGNIFICANT STRENGTHENING DURING THE NEXT COUPLE OF DAYS. AFTERWARDS...DYNAMICAL MODELS PREDICT THAT THE UPPER-LEVEL WINDS WILL BECOME MORE CONDUCIVE FOR INTENSIFICATION WITH INCREASING UPPER-LEVEL ANTICYCLONIC OUTFLOW OVER THE SYSTEM. THE OFFICIAL WIND SPEED FORECAST IS THE SAME AS THE PREVIOUS ONE...AND IS IN CLOSE AGREEMENT WITH THE LATEST LGEM GUIDANCE. AN SSM/IS IMAGE FROM A FEW HOURS AGO INDICATED THAT THE CENTER WAS LOCATED A LITTLE FARTHER NORTH OF THE PREVIOUS ESTIMATES...AND THE WORKING BEST TRACK HAS BEEN ADJUSTED ACCORDINGLY. EVEN WITH THE SLIGHT NORTHWARD RELOCATION...THE INITIAL MOTION ESTIMATE... 325/9...IS NOT CHANGED MUCH FROM THE PREVIOUS ADVISORY. LESLIE IS MOVING TOWARD A BREAK IN THE SUBTROPICAL RIDGE...HOWEVER...THE GLOBAL MODELS INDICATE THAT THE RIDGE WILL BUILD SOMEWHAT TO THE NORTHWEST AND NORTH OF THE TROPICAL CYCLONE IN A FEW DAYS. AS A RESULT...THE FORWARD MOTION OF THE STORM IS LIKELY TO SLOW DURING THE NEXT 48-72 HOURS. THE OFFICIAL TRACK FORECAST IS NOT TOO DIFFERENT FROM THE PREVIOUS ONE AND NOT FAR FROM THE MULTI-MODEL CONSENSUS TVCA. THIS IS BETWEEN THE LATEST GFS AND GFS ENSEMBLE MEAN FORECASTS AND THE ECMWF TRACK...WITH THE LATTER MODEL BEING FASTER THAN MOST OF THE OTHER GUIDANCE. FORECAST POSITIONS AND MAX WINDS INIT 03/0300Z 23.4N 61.7W 50 KT 60 MPH 12H 03/1200Z 24.4N 62.2W 50 KT 60 MPH 24H 04/0000Z 25.4N 62.6W 50 KT 60 MPH 36H 04/1200Z 26.0N 62.7W 50 KT 60 MPH 48H 05/0000Z 26.6N 62.7W 50 KT 60 MPH 72H 06/0000Z 27.5N 62.7W 60 KT 70 MPH 96H 07/0000Z 28.5N 63.0W 65 KT 75 MPH 120H 08/0000Z 30.0N 63.5W 70 KT 80 MPH $$ FORECASTER PASCH