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#531813 (Received by flhurricane at: 4:35 PM 04.Aug.2012) TCDAT5 TROPICAL STORM ERNESTO DISCUSSION NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012 500 PM EDT SAT AUG 04 2012 A RECONNAISSANCE PLANE EARLIER THIS MORNING FOUND A WEAKER CYCLONE...BUT DURING THE LAST PASS THROUGH THE CENTER AROUND NOON...THE PLANE REPORTED THAT THE CENTRAL PRESSURE HAD DROPPED TO 1004 MB FROM 1008 MB...AND FOUND A BETTER DEFINED CIRCULATION CENTER. SINCE THAT TIME...THE SATELLITE PRESENTATION HAS CONTINUED TO INCREASE IN ORGANIZATION. THE CENTER IS EMBEDDED WITHIN A CIRCULAR AREA OF DEEP CONVECTION...AND THE OUTFLOW IS WELL ESTABLISHED WHICH IS NOT COMMON FOR A CYCLONE IN THE CENTRAL CARIBBEAN. T-NUMBERS WERE 3.5 AND 3.0 AT 1800 UTC...AND OBJECTIVE NUMBERS HAVE REACHED 4.3 ON THE DVORAK SCALE DURING THE PAST HOUR. ON THIS BASIS...THE INTENSITY HAS BEEN CONSERVATIVELY BEEN ADJUSTED UPWARD TO 50 KNOTS. HOWEVER... GIVEN THE SATELLITE PRESENTATION... THE NEXT RECONNAISSANCE PLANE COULD FIND STRONGER WINDS. AS INDICATED IN THE PREVIOUS ADVISORY...I DO NOT HAVE ANY REASONS TO FORECAST WEAKENING AS SOME OF THE DYNAMICAL MODELS PREDICT... INCLUDING THE HWRF AND THE GFDL. THE SHEAR IS LOW AHEAD OF THE CYCLONE AND ERNESTO WILL MOVE OVER AN OCEAN WITH HIGHER HEAT CONTENT. GIVEN SUCH CONDITIONS...THE OFFICIAL FORECAST CALLS FOR ERNESTO TO BECOME A HURRICANE IN THE WESTERN CARIBBEAN AS SUGGESTED BY THE SHIPS AND LGEM MODELS. ERNESTO CONTINUES TO MOVE TOWARD THE WEST OR 280 DEGREES AT 16 KNOTS...EMBEDDED IN THE FLOW SOUTH OF THE SUBTROPICAL RIDGE. THIS GENERAL TRACK IS EXPECTED TO CONTINUE FOR THE NEXT 24 TO 48 HOURS. AFTER THAT...THE SUBTROPICAL HIGH IS FORECAST TO WEAKEN...RESULTING IN ERNESTO TURNING MORE TOWARD THE WEST-NORTHWEST WITH A DECREASE IN FORWARD SPEED. THE OFFICIAL FORECAST IS VERY CLOSE TO THE SOLUTION OF MOST THE GLOBAL MODELS...BRINGING ERNESTO OVER THE NORTHWESTERN CARIBBEAN AND ACROSS THE YUCATAN PENINSULA. AT THIS TIME...THE NHC FORECAST DISREGARDS THE NORTHWARD TURN INDICATED BY THE GFDL/HWRF MODEL PAIR. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 14.8N 70.1W 50 KT 60 MPH 12H 05/0600Z 15.2N 72.6W 50 KT 60 MPH 24H 05/1800Z 15.7N 76.0W 55 KT 65 MPH 36H 06/0600Z 16.0N 79.0W 65 KT 75 MPH 48H 06/1800Z 16.5N 81.5W 70 KT 80 MPH 72H 07/1800Z 18.0N 84.5W 75 KT 85 MPH 96H 08/1800Z 19.5N 87.0W 80 KT 90 MPH 120H 09/1800Z 21.5N 90.5W 60 KT 70 MPH $$ FORECASTER AVILA |