000 WTNT45 KNHC 080247 TCDAT5 HURRICANE ERNESTO DISCUSSION NUMBER 27 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012 1000 PM CDT TUE AUG 07 2012 TECHNICAL ISSUES PREVENTED A RECON FLIGHT FROM INVESTIGATING ERNESTO THIS EVENING. HOWEVER...IMAGERY FROM THE BELIZE RADAR INDICATE THE HURRICANE HAD A WELL-DEFINED 15-NMI DIAMETER EYE EARLIER THIS EVENING...BUT THE EYE HAS BECOME A LITTLE RAGGED OVER THE PAST COUPLE OF HOURS. THE INITIAL INTENSITY HAS BEEN INCREASED TO 75 KT BASED ON AN INTENSITY ESTIMATE OF 77 KT FROM BOTH TAFB AND SAB. RADAR FIXES OVER THE PAST 6 HOURS INDICATE ERNESTO HAS BEEN MOVING WESTWARD...OR 270/13 KT. THE EYE OF THE HURRICANE IS CURRENTLY LOCATED OVER THE NORTHERN BANCO CHINCHORRO ISLANDS OF MEXICO...AND WILL MOVING ONSHORE THE SOUTHERN COAST OF YUCATAN SHORTLY. THE NHC MODEL GUIDANCE REMAINS IN VERY GOOD AGREEMENT ON ERNESTO MOVING WESTWARD TO WEST-NORTHWESTWARD ACROSS SOUTHERN YUCATAN TONIGHT AND WEDNESDAY...AND EMERGING OVER THE BAY OF CAMPECHE BY WEDNESDAY AFTERNOON OR EVENING. LOW- TO MID-LEVEL RIDGING TO THE NORTH AND NORTHWEST OF THE CYCLONE AS IT MOVES OVER THE BAY OF CAMPECHE IS EXPECTED TO TURN ERNESTO TOWARD THE WEST-SOUTHWEST BY 48 HOURS AS IT NEARS MAINLAND MEXICO. AFTER THE SECOND LANDFALL OCCURS... ERNESTO IS EXPECTED TO RAPIDLY WEAKEN INTO A REMNANT LOW OVER THE HIGH MOUNTAINS OF INTERIOR MEXICO BY 96 HOURS. THE OFFICIAL FORECAST TRACK IS SIMILAR TO BUT SLIGHTLY SOUTH OF THE PREVIOUS FORECAST TRACK...AND LIES CLOSE TO THE CONSENSUS MODELS. LITTLE IF ANY ADDITIONAL STRENGTHENING IS EXPECTED BEFORE LANDFALL OCCURS. ERNESTO SHOULD WEAKEN RAPIDLY AS IT PASSES OVER YUCATAN TONIGHT AND TOMORROW...BUT THE INCREASE IN LOW-LEVEL FRICTIONAL CONVERGENCE MAY ACTUALLY HELP TO TIGHTEN UP THE CIRCULATION BEFORE IT EMERGES OVER THE BAY OF CAMPECHE IN 18-24 HOURS. THIS APPEARS TO BE ONE OF THE DRIVING MECHANISMS IN THE HWRF AND GFDL MODELS... WHICH MAKE ERNESTO A HURRICANE AGAIN BY 48 HOURS WHEN IT IS OVER THE SOUTHERN BAY OF CAMPECHE. THIS SEEMS REASONABLE GIVEN THE CURRENT AND EXPECTED FAVORABLE ANTICYCLONIC OUTFLOW OVER ERNESTO. RAPID WEAKENING AND DISSIPATION SHOULD OCCUR AFTER THE SECOND LANDFALL IN MAINLAND MEXICO DUE TO VERY HIGH TERRAIN. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY...AND FOLLOWS A BLEND OF THE LGEM...GFDL...AND HWRF MODELS. 34-KT WIND RADII WERE EXPANDED IN THE EASTERN SEMICIRCLE BASED ON WIND REPORTS FROM THE LAST RECON FLIGHT AND NOAA BUOY 42056. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 18.7N 87.7W 75 KT 85 MPH...OVER BANCO CHINCHORRO 12H 08/1200Z 19.1N 89.5W 40 KT 45 MPH...INLAND YUCATAN 24H 09/0000Z 19.4N 91.9W 45 KT 50 MPH...OVER WATER 36H 09/1200Z 19.4N 94.0W 55 KT 65 MPH 48H 10/0000Z 19.2N 95.8W 65 KT 75 MPH 72H 11/0000Z 18.7N 98.5W 25 KT 30 MPH...DISSIPATING INLAND 96H 12/0000Z...DISSIPATED $$ FORECASTER STEWART