000 WTPZ44 KNHC 201441 TCDEP4 HURRICANE DORA DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042011 800 AM PDT WED JUL 20 2011 SATELLITE IMAGES INDICATE CONSIDERABLE CONVECTION NEAR THE CENTER OF DORA ALONG WITH PRONOUNCED BANDING FEATURES. ALTHOUGH AN EYE IS NOT APPARENT IN CONVENTIONAL IMAGERY...MICROWAVE DATA SHOW THAT THE INNER CORE IS BECOMING BETTER DEFINED. INTENSITY ESTIMATES ARE INCREASING...AND THE WIND SPEED IS RAISED TO 80 KT. WHILE THE HURRICANE HAS BEEN INTENSIFYING STEADILY DURING ITS LIFETIME...IT HAS HAD SOME TROUBLE DEVELOPING AN INNER CORE. PERHAPS THIS IS DUE TO SOME MID-LEVEL SHEAR AS INDICATED BY LOCAL NHC SHEAR DIAGNOSTICS. WHATEVER THE CASE...AS THE MID-LEVEL FLOW WEAKENS DURING THE NEXT 36 HOURS...DORA SHOULD INTENSIFY...AND COULD RAPIDLY STRENGTHEN. THE STATISTICAL MODELS ARE NOW IN BETTER AGREEMENT WITH THE GFDL MODEL...SHOWING THIS SYSTEM PEAKING IN A DAY OR TWO AS A MAJOR HURRICANE. THE NEW NHC FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE. A RAPID DECLINE IN STRENGTH IS LIKELY BY LATE FRIDAY AS DORA MOVES ACROSS RATHER COLD WATERS SOUTHWEST OF BAJA CALIFORNIA. THE CYCLONE SHOULD BECOME A REMNANT LOW IN ABOUT 5 DAYS OVER WATERS LESS THAN 21C. DORA CONTINUES SPEEDING ALONG TOWARD THE WEST-NORTHWEST AT 16 KT. A STRONG MID-LEVEL RIDGE CENTERED OVER THE CENTRAL UNITED STATES IS FORECAST TO WEAKEN AND MOVE EASTWARD OVER THE NEXT COUPLE OF DAYS. THIS SHOULD CAUSE DORA TO SLOW DOWN AND TURN TOWARD THE NORTHWEST. THE NHC FORECAST IS VERY CLOSE TO THE PREVIOUS ONE THROUGH 48 HOURS...JUST A SMIDGE FASTER. IN THE EXTENDED RANGE...THERE REMAINS SOME UNCERTAINTY REGARDING THE STRENGTH OF A NARROW RIDGE BETWEEN DORA AND A TROUGH MOVING INTO THE WESTERN UNITED STATES. MODELS ARE GENERALLY SHOWING A STRONGER RIDGE...CAUSING A LEFTWARD SHIFT IN THE TRACK GUIDANCE...AND THE NEW NHC FORECAST HAS BEEN MOVED IN THAT DIRECTION. FORECAST POSITIONS AND MAX WINDS INIT 20/1500Z 14.9N 103.0W 80 KT 90 MPH 12H 21/0000Z 15.9N 104.6W 90 KT 105 MPH 24H 21/1200Z 17.1N 106.5W 105 KT 120 MPH 36H 22/0000Z 18.3N 108.0W 110 KT 125 MPH 48H 22/1200Z 19.3N 109.2W 105 KT 120 MPH 72H 23/1200Z 20.8N 111.8W 80 KT 90 MPH 96H 24/1200Z 22.5N 115.0W 50 KT 60 MPH 120H 25/1200Z 24.0N 118.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ FORECASTER BLAKE 000 WTPZ44 KNHC 201441 TCDEP4 HURRICANE DORA DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042011 800 AM PDT WED JUL 20 2011 SATELLITE IMAGES INDICATE CONSIDERABLE CONVECTION NEAR THE CENTER OF DORA ALONG WITH PRONOUNCED BANDING FEATURES. ALTHOUGH AN EYE IS NOT APPARENT IN CONVENTIONAL IMAGERY...MICROWAVE DATA SHOW THAT THE INNER CORE IS BECOMING BETTER DEFINED. INTENSITY ESTIMATES ARE INCREASING...AND THE WIND SPEED IS RAISED TO 80 KT. WHILE THE HURRICANE HAS BEEN INTENSIFYING STEADILY DURING ITS LIFETIME...IT HAS HAD SOME TROUBLE DEVELOPING AN INNER CORE. PERHAPS THIS IS DUE TO SOME MID-LEVEL SHEAR AS INDICATED BY LOCAL NHC SHEAR DIAGNOSTICS. WHATEVER THE CASE...AS THE MID-LEVEL FLOW WEAKENS DURING THE NEXT 36 HOURS...DORA SHOULD INTENSIFY...AND COULD RAPIDLY STRENGTHEN. THE STATISTICAL MODELS ARE NOW IN BETTER AGREEMENT WITH THE GFDL MODEL...SHOWING THIS SYSTEM PEAKING IN A DAY OR TWO AS A MAJOR HURRICANE. THE NEW NHC FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE. A RAPID DECLINE IN STRENGTH IS LIKELY BY LATE FRIDAY AS DORA MOVES ACROSS RATHER COLD WATERS SOUTHWEST OF BAJA CALIFORNIA. THE CYCLONE SHOULD BECOME A REMNANT LOW IN ABOUT 5 DAYS OVER WATERS LESS THAN 21C. DORA CONTINUES SPEEDING ALONG TOWARD THE WEST-NORTHWEST AT 16 KT. A STRONG MID-LEVEL RIDGE CENTERED OVER THE CENTRAL UNITED STATES IS FORECAST TO WEAKEN AND MOVE EASTWARD OVER THE NEXT COUPLE OF DAYS. THIS SHOULD CAUSE DORA TO SLOW DOWN AND TURN TOWARD THE NORTHWEST. THE NHC FORECAST IS VERY CLOSE TO THE PREVIOUS ONE THROUGH 48 HOURS...JUST A SMIDGE FASTER. IN THE EXTENDED RANGE...THERE REMAINS SOME UNCERTAINTY REGARDING THE STRENGTH OF A NARROW RIDGE BETWEEN DORA AND A TROUGH MOVING INTO THE WESTERN UNITED STATES. MODELS ARE GENERALLY SHOWING A STRONGER RIDGE...CAUSING A LEFTWARD SHIFT IN THE TRACK GUIDANCE...AND THE NEW NHC FORECAST HAS BEEN MOVED IN THAT DIRECTION. FORECAST POSITIONS AND MAX WINDS INIT 20/1500Z 14.9N 103.0W 80 KT 90 MPH 12H 21/0000Z 15.9N 104.6W 90 KT 105 MPH 24H 21/1200Z 17.1N 106.5W 105 KT 120 MPH 36H 22/0000Z 18.3N 108.0W 110 KT 125 MPH 48H 22/1200Z 19.3N 109.2W 105 KT 120 MPH 72H 23/1200Z 20.8N 111.8W 80 KT 90 MPH 96H 24/1200Z 22.5N 115.0W 50 KT 60 MPH 120H 25/1200Z 24.0N 118.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ FORECASTER BLAKE