000 WTNT45 KNHC 062040 TCDAT5 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