000 WTPZ44 KNHC 040839 TCDEP4 HURRICANE MARIE DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP142008 200 AM PDT SAT OCT 04 2008 MARIE CONTINUES TO SHOW A POORLY-DEFINED EYE IN INFRARED SATELLITE IMAGERY THIS MORNING. SEVERAL RECENT MICROWAVE OVERPASSES ALSO SHOW THE EYE...WITH INDICATIONS THAT THE SURROUNDING EYEWALL IS ERODING ON THE SOUTH SIDE. SATELLITE INTENSITY ESTIMATES HAVE INCREASED TO 77 KT FROM TAFB...AND REMAIN 65 KT FROM SAB. BASED ON THIS...THE INITIAL INTENSITY IS INCREASED TO 70 KT. ANALYSES FROM CIMSS AT THE UNIVERSITY OF WISCONSIN SHOW THAT MARIE IS NOW EXPERIENCING ABOUT 10 KT OF SOUTHWESTERLY VERTICAL WIND SHEAR... WITH GOOD CIRRUS OUTFLOW IN THE NORTHEASTERN SEMICIRCLE AND POOR ELSEWHERE. THE INITIAL MOTION IS NOW 005/3. MARIE IS CURRENTLY LOCATED IN A BREAK IN THE SUBTROPICAL RIDGE TO THE EAST OF AN ANTICYCLONE CENTERED TO THE EAST OF THE HAWAIIAN ISLANDS...AND TO THE SOUTH OF A STRONG DEEP-LAYER TROUGH ALONG THE U. S. WEST COAST. SATELLITE IMAGERY SUGGESTS A SMALL DEEP-LAYER RIDGE HAS FORMED BETWEEN MARIE AND TROPICAL DEPRESSION FIFTEEN-E...AND THIS FEATURE MAY BE THE CAUSE OF THE CURRENT NORTHWARD MOTION. THE LARGE-SCALE MODELS FORECAST MID/UPPER-LEVEL RIDGING TO BUILD NORTH OF MARIE IN 18-36 HR...WHICH SHOULD ALLOW THE CYCLONE TO RESUME A WESTWARD MOTION. UNTIL THEN...A SLOW NORTHWARD DRIFT IS EXPECTED. THE FORECAST TRACK NOW CALLS FOR A NORTHWARD MOTION FOR 12 HR OR SO...FOLLOWED BY A GRADUAL TURN TOWARD THE WEST. THIS PART OF THE FORECAST TRACK IS IN THE CENTER OF THE GUIDANCE ENVELOPE. AFTER 72 HR...THE LARGE-SCALE MODELS FORECAST PART OF THE DEEP-LAYER TROUGH TO SPLIT OFF AND MOVE SOUTHWARD WEST OF BAJA CALIFORNIA. THE GFDL...WHICH HAS MARIE MOVING MORE SLOWLY WESTWARD UNDER THE RIDGE...TURNS THE CYCLONE SOUTHWESTWARD IN RESPONSE TO THE TROUGH. THE NOGAPS AND HWRF...WHICH HAVE A FASTER WESTWARD MOTION...SHOW THE TROUGH HAVING LITTLE IMPACT ON MARIE'S TRACK. SINCE THE FORECAST TRACK HAS MARIE MOVING WESTWARD AT A SPEED BETWEEN THAT OF THE ABOVE-MENTIONED MODELS...IT WILL SHOW A SMALL SOUTHWARD NUDGE AFTER 96 HR. THE TRACK AFTER 72 HR IS A LITTLE NORTH OF THE MODEL CONSENSUS. THE LARGE-SCALE MODELS CONTINUE TO FORECAST A LIGHT-SHEAR ENVIRONMENT NEAR MARIE THROUGH THE FORECAST PERIOD. HOWEVER...THE NORTHWARD MOTION IS TAKING THE CENTER NORTH OF THE 26C SEA SURFACE TEMPERATURE ISOTHERM...AND THE NORTHWARD SHIFT IN THE FORECAST TRACK SUGGESTS MARIE WILL ENCOUNTER COLDER WATER THAN PREVIOUSLY EXPECTED. ALL INTENSITY GUIDANCE FORECASTS A GRADUAL WEAKENING... AND THE INTENSITY FORECAST FOLLOWS THIS SCENARIO. THE INTENSITY FORECAST HAS MARIE WEAKENING TO A TROPICAL STORM IN 24-36 HR...A TROPICAL DEPRESSION IN ABOUT 96 HR...AND A REMNANT LOW IN ABOUT 120 HR. IT SHOULD BE NOTED THAT THE FORECAST WESTWARD MOTION IS ROUGHLY PARALLEL TO THE SST ISOTHERMS...SO SMALL DEVIATIONS TO THE NORTH OR SOUTH OF THE TRACK COULD MAKE A SIGNIFICANT DIFFERENCE IN THE SSTS THAT MARIE ENCOUNTERS. FORECAST POSITIONS AND MAX WINDS INITIAL 04/0900Z 18.4N 122.0W 70 KT 12HR VT 04/1800Z 18.6N 122.0W 70 KT 24HR VT 05/0600Z 19.0N 122.4W 65 KT 36HR VT 05/1800Z 19.3N 123.3W 55 KT 48HR VT 06/0600Z 19.4N 124.4W 45 KT 72HR VT 07/0600Z 19.5N 127.5W 35 KT 96HR VT 08/0600Z 19.5N 130.5W 30 KT 120HR VT 09/0600Z 19.0N 133.0W 25 KT...REMNANT LOW $$ FORECASTER BEVEN