Tropical Storm ERNESTO

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TROPICAL STORM ERNESTO DISCUSSION NUMBER  21
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
500 PM EDT MON AUG 06 2012
 
AFTER THE SUDDEN STRENGTHENING EPISODE THAT OCCURRED THIS
MORNING...THE LAST COUPLE OF CENTER PENETRATIONS BY THE HURRICANE
HUNTERS INDICATED THAT THE INTENSITY HAS LEVELED OFF.  THE CENTRAL
PRESSURE HAS STOPPED FALLING...FOR NOW...AND THE INTENSITY OF THE
CORE CONVECTION...AS MEASURED BY CLOUD TOP TEMPERATURES AND
LIGHTNING DATA...HAS NOTICEABLY DIMINISHED.  THE CURRENT WIND SPEED
IS KEPT AT 55 KT...WHICH IS CONSISTENT WITH THE LAST SFMR
OBSERVATIONS OVER THE NORTHEAST QUADRANT OF THE CIRCULATION. 
UPPER-LEVEL OUTFLOW HAS BECOME FAIRLY WELL DEFINED AS COMPARED TO
THE LAST FEW DAYS.  ALTHOUGH THE CYCLONE HAS NOT STRENGTHENED
FURTHER OVER THE PAST FEW HOURS...ERNESTO IS IN A WEAK SHEAR
ENVIRONMENT AND HAS THE POTENTIAL TO BECOME A HURRICANE BEFORE
REACHING THE YUCATAN PENINSULA.  THAT IS THE SCENARIO SHOWN BY THE
OFFICIAL INTENSITY FORECAST...WHICH IS IN GOOD AGREEMENT WITH THE
NUMERICAL INTENSITY MODEL CONSENSUS.

AFTER THE EARLIER REPOSITIONING OF THE CENTER...THERE IS MORE
CONFIDENCE IN THE INITIAL MOTION ESTIMATE...WHICH IS NOW 295/10. 
OVER THE NEXT FEW DAYS...A 500 MB TROUGH IS FORECAST TO MOVE INTO
THE EASTERN UNITED STATES...TO THE NORTH OF A RATHER WEAK RIDGE
OVER THE GULF OF MEXICO.  THE GLOBAL MODELS...IN PARTICULAR THE GFS
AND THE ECMWF...CONTINUE TO INDICATE THAT THE RIDGE WILL NOT BE
WEAK ENOUGH TO ALLOW ERNESTO TO MOVE VERY FAR NORTH OVER THE GULF. 
THE OFFICIAL TRACK FORECAST IS ONLY SLIGHTLY NORTH OF THE PREVIOUS
ONE AND IS CLOSE TO THE LATEST DYNAMICAL MODEL CONSENSUS.  THIS IS
ALSO SIMILAR TO THE GFS...AND A LITTLE NORTH OF THE NEW ECMWF
TRACK. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  06/2100Z 16.2N  81.6W   55 KT  65 MPH
 12H  07/0600Z 16.9N  83.2W   60 KT  70 MPH
 24H  07/1800Z 18.0N  85.5W   70 KT  80 MPH
 36H  08/0600Z 18.7N  87.8W   75 KT  85 MPH
 48H  08/1800Z 19.2N  90.0W   60 KT  70 MPH...INLAND
 72H  09/1800Z 19.5N  94.0W   60 KT  70 MPH
 96H  10/1800Z 19.5N  96.5W   65 KT  75 MPH
120H  11/1800Z 19.0N  99.0W   25 KT  30 MPH...INLAND
 
$$
FORECASTER PASCH
 
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