000 WTPZ44 KNHC 030240 TCDEP4 HURRICANE DALILA DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013 800 PM PDT TUE JUL 02 2013 THE CLOUD PATTERN OF DALILA HAS CHANGED LITTLE IN ORGANIZATION DURING THE LAST SEVERAL HOURS...WITH THE CYCLONE STILL MAINTAINING A SMALL AND FAIRLY SYMMETRIC CDO. A 0016 UTC SSMI/S PASS DID... HOWEVER...SHOW A SLIGHT DEGRADATION OF THE INNER CORE...WITH THE EYEWALL OPEN TO THE EAST. THE MID-LEVEL CENTER ALSO WAS DISPLACED NORTHWEST OF THE LOW-LEVEL CENTER...SUGGESTING THAT SOUTHEASTERLY SHEAR IS STILL AFFECTING THE CYCLONE. THE INITIAL INTENSITY IS KEPT AT 65 KT IN AGREEMENT WITH A TAFB DVORAK INTENSITY ESTIMATE OF T4.0/65 KT. THE STATISTICAL MODEL GUIDANCE SHOWS DALILA CHANGING LITTLE IN STRENGTH DURING THE NEXT 2-3 DAYS...EVEN THOUGH THE HURRICANE SHOULD BE PASSING OVER RELATIVELY WARM WATERS. THE MAIN OBSTACLE TO ANY FURTHER STRENGTHENING IS LIKELY RELATED TO MODERATE EAST- SOUTHEASTERLY TO SOUTHEASTERLY WIND SHEAR FORECAST TO PREVAIL OVER THE CYCLONE. THE ECMWF SHOWS DALILA QUICKLY WEAKENING AS A RESULT OF THE ENTRAINMENT OF A LAYER OF DRY AIR TO THE WEST OF DALILA. IT IS DIFFICULT...HOWEVER...TO IMAGINE THIS SCENARIO...GIVEN THAT THE UPPER-LEVEL FLOW IS FROM THE EAST. THE NHC INTENSITY FORECAST CONTINUES TO LEAN ON THE GFS-BASED MODEL GUIDANCE AND IS NEAR A BLEND OF THE SHIPS/LGEM THROUGH 72 HOURS...AND THEN NEAR THE MULTI-MODEL INTENSITY CONSENSUS AIDS BEYOND THAT TIME. DALILA IS NOT MOVING MUCH. A LONG-TERM AVERAGE OF SATELLITE FIXES YIELDS A HIGHLY UNCERTAIN INITIAL MOTION ESTIMATE OF 270/02. HOWEVER...RECENT MICROWAVE FIXES SUGGEST THAT A WEST-SOUTHWESTWARD TO SOUTHWESTWARD DRIFT MAY HAVE COMMENCED. A MID-LEVEL TROUGH ACROSS NORTHERN MEXICO HAS TEMPORARILY WEAKENED THE SUBTROPICAL RIDGE AND CREATED A WEAK STEERING ENVIRONMENT OVER THE CYCLONE. HOWEVER...THE STRONG HEAT RIDGE OVER THE WESTERN UNITED STATES IS FORECAST TO MOVE SOUTHEASTWARD DURING THE NEXT COUPLE OF DAYS...WHICH SHOULD CAUSE DALILA TO TURN SOUTH OF WEST WITH SOME MINOR INCREASE IN FORWARD SPEED. THE TRACK GUIDANCE REMAINS DIVERSE...WITH THE ECMWF STILL FORECASTING A WEAK CYCLONE MOVING SOUTHWARD AND DISSIPATING. THE GFS CONTINUES TO SHOW A STRONGER SYSTEM MOVING ON A MORE WESTERLY TRACK. THE NEW NHC TRACK FORECAST CONTINUES TO WEIGH THE GFS SOLUTION MORE...AND IS BETWEEN THE PREVIOUS FORECAST AND THE MULTI-MODEL CONSENSUS TVCE THROUGH 72 HOURS...AND CLOSER TO THE GFS LATE IN THE PERIOD. FORECAST POSITIONS AND MAX WINDS INIT 03/0300Z 18.3N 107.3W 65 KT 75 MPH 12H 03/1200Z 18.1N 107.6W 65 KT 75 MPH 24H 04/0000Z 17.7N 108.2W 65 KT 75 MPH 36H 04/1200Z 17.4N 108.9W 65 KT 75 MPH 48H 05/0000Z 17.4N 109.9W 60 KT 70 MPH 72H 06/0000Z 17.6N 111.9W 55 KT 65 MPH 96H 07/0000Z 18.0N 114.0W 40 KT 45 MPH 120H 08/0000Z 18.5N 116.5W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ FORECASTER KIMBERLAIN