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Tropical Storm CARLOTTA (Text)

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TROPICAL STORM CARLOTTA DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP032012
800 AM PDT THU JUN 14 2012

DURING THE PAST SEVERAL HOURS...CARLOTTA HAS DEVELOPED A CENTRAL
CONVECTIVE FEATURE SURROUNDED BY A COMPLEX OF OUTER RAINBANDS. 
SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM TAFB AND 35 KT FROM
SAB...AND A RECENT AMSU INTENSITY ESTIMATE FROM CIMSS IS 50 KT. 
THE INITIAL INTENSITY IS RAISED TO 40 KT...AND THIS COULD BE
CONSERVATIVE.  THE CIRRUS OUTFLOW IS GOOD IN THE NORTH AND SOUTH
QUADRANTS.

THE INITIAL MOTION IS 325/8.  CARLOTTA IS CURRENTLY BEING STEERED BY
A MID/UPPER-LEVEL RIDGE OVER THE WESTERN CARIBBEAN AND A SMALL
UPPER-LEVEL TROUGH SEEN IN WATER VAPOR IMAGERY TO THE WEST OF THE
CYCLONE.  THE DYNAMICAL MODELS FORECAST THIS PATTERN TO PERSIST FOR
48 HR OR SO...FOLLOWED BY A MID/UPPER-LEVEL RIDGE BUILDING OVER
NORTHERN MEXICO.  THIS EVOLUTION SHOULD CAUSE CARLOTTA TO MOVE
GENERALLY NORTHWESTWARD FOR 36-48 HR...FOLLOWED BY A MORE WESTWARD
MOTION.  THE TRACK GUIDANCE HAS SHIFTED WESTWARD SINCE THE LAST
ADVISORY AND IS IN FAIR AGREEMENT THAT CARLOTTA SHOULD TRACK NEAR
OR ALONG THE COAST OF MEXICO FROM 36-72 HR.  THE NEW FORECAST TRACK
IS ALSO SHIFTED TO THE WEST...BUT LIES ON THE EASTERN SIDE OF THE
GUIDANCE ENVELOPE.  AFTER 72 HR...THE MEXICAN RIDGE IS FORECAST
TO WEAKEN AS A MID/UPPER-LEVEL TROUGH DEVELOPS OVER THE GULF OF
MEXICO.  THIS SHOULD LEAVE THE CYCLONE IN AN AREA OF WEAK STEERING
CURRENTS WITH A VERY SLOW MOTION.

CARLOTTA IS CURRENTLY IN AN ENVIRONMENT OF LIGHT VERTICAL WIND SHEAR
AND OVER 30C SEA SURFACE TEMPERATURES.  THESE CONDITIONS ARE
FAVORABLE FOR STRENGTHENING...AND THE INTENSITY FORECAST NOW CALLS
FOR CARLOTTA TO REACH AN INTENSITY OF 80 KT IN 48 HR.  THE RAPID
INTENSIFICATION INDEX OF THE SHIPS MODEL SHOWS A 50-60 PERCENT
CHANCE OF 25-KT STRENGTHENING DURING THE NEXT 24 HR...AND ABOUT A
25 PERCENT CHANCE OF 40-KT STRENGTHENING...SO THE EARLY PART OF THE
CURRENT FORECAST COULD BE CONSERVATIVE.  AFTER 48 HR...THE
INTENSITY IS LIKELY TO BE CONTROLLED BY HOW CLOSE THE CENTER IS TO
THE COAST.  IF CARLOTTA MOVES INLAND...IT COULD DISSIPATE OVER THE
MOUNTAINS OF MEXICO.  EVEN IF IT STAYS OFFSHORE...IT IS EXPECTED TO
BE CLOSE ENOUGH TO INTERACT WITH THE MOUNTAINS AND WEAKEN AS SHOWN
BY THE GFDL AND HWRF MODELS...AND THAT IS THE SCENARIO USED IN THE
INTENSITY FORECAST.
  
USERS ARE AGAIN REMINDED NOT TO FOCUS ON THE EXACT FORECAST TRACK AS
TYPICAL NHC FORECAST ERRORS AT 48 AND 72 HOURS ARE 80-110 N MI...
AND ANY DEVIATION TO THE NORTH AND EAST OF THE FORECAST TRACK WOULD
BRING THE CENTER OF CARLOTTA ONTO THE COAST OF MEXICO.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/1500Z 10.9N  93.6W   40 KT  45 MPH
 12H  15/0000Z 11.9N  94.5W   50 KT  60 MPH
 24H  15/1200Z 13.3N  95.6W   60 KT  70 MPH
 36H  16/0000Z 14.6N  96.7W   75 KT  85 MPH
 48H  16/1200Z 15.6N  97.7W   80 KT  90 MPH...NEAR COAST
 72H  17/1200Z 16.5N  99.5W   60 KT  70 MPH...NEAR COAST
 96H  18/1200Z 16.5N 100.0W   45 KT  50 MPH...NEAR COAST
120H  19/1200Z 16.0N 100.0W   45 KT  50 MPH
 
$$
FORECASTER BEVEN
 
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