Hurricane DALILA
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HURRICANE DALILA DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
200 AM PDT WED JUL 03 2013
EARLIER MICROWAVE IMAGERY SUGGESTED THAT THE CORE CONVECTION OF
DALILA HAD AGAIN BECOME SOMEWHAT DISORGANIZED...POSSIBLY DUE TO
SHEAR INDICATED BY CIRRUS CLOUDS MOVING INTO THE CYCLONE FROM THE
EAST. HOWEVER...THE CLOUD TOP TEMPERATURES REMAIN PERSISTENTLY
NEAR OR COLDER THAN -80C...AND THE SATELLITE INTENSITY ESTIMATES
FROM TAFB AND SAB HAVE NOT CHANGED DURING THE PAST 12 HOURS. THE
INITIAL INTENSITY THUS REMAINS 65 KT...ALTHOUGH IT IS POSSIBLE THAT
THIS IS GENEROUS.
THE INITIAL MOTION IS AN UNCERTAIN 225/2. THERE IS LITTLE CHANGE IN
EITHER THE TRACK FORECAST PHILOSOPHY OR THE MODEL GUIDANCE SINCE
THE LAST ADVISORY. A STRONG DEEP-LAYER RIDGE OVER THE WESTERN
UNITED STATES SHOULD BUILD SOUTHEASTWARD DURING THE NEXT SEVERAL
DAYS AS A TROPICAL DISTURBANCE SOUTH OF EASTERN MEXICO MOVES TOWARD
DALILA. THIS EVOLUTION SHOULD CAUSE THE CYCLONE TO MOVE GENERALLY
WEST-SOUTHWESTWARD FOR 36 HOURS OR SO...FOLLOWED BY A WESTWARD
MOTION. THE GUIDANCE BECOMES QUITE DIVERSE AFTER 72 HOURS...WITH
FORECAST TRACKS SPREAD BETWEEN A SOUTHWESTWARD MOTION AND A
NORTHWESTWARD MOTION. THIS PORTION OF THE TRACK WILL SHOW A
GENERAL WEST-NORTHWESTWARD MOTION NEAR THE CENTER OF THE GUIDANCE
ENVELOPE. THE NEW FORECAST TRACK IS SIMILAR TO THE PREVIOUS TRACK.
THE ECMWF...UKMET...AND CANADIAN MODELS FORECAST DALILA TO DISSIPATE
COMPLETELY DURING THE NEXT 3-5 DAYS...WHILE THE GFS AND NAVGEM
MODEL SHOW IT SURVIVING AS A TROPICAL CYCLONE OR LOW PRESSURE AREA
FOR 5 DAYS. THE DISSIPATION SCENARIO IS SUPPORTED BY DRY AIR SEEN
NEAR THE CYCLONE IN MICROWAVE DATA...WHILE THE SURVIVAL SCENARIO IS
SUPPORTED BY WARM SEA SURFACE TEMPERATURES DURING THE FIRST 3 DAYS
OF THE NEW FORECAST TRACK. THE INTENSITY FORECAST GOES WITH THE
SURVIVAL SCENARIO...CALLING FOR DALILA TO MAINTAIN HURRICANE
STRENGTH FOR 24 HOURS WITH GRADUAL WEAKENING THEREAFTER. THE
INTENSITY FORECAST HAS BEEN TWEAKED SLIGHTLY TO MATCH THE INTENSITY
CONSENSUS FORECAST.
FORECAST POSITIONS AND MAX WINDS
INIT 03/0900Z 18.1N 107.5W 65 KT 75 MPH
12H 03/1800Z 17.8N 107.9W 65 KT 75 MPH
24H 04/0600Z 17.4N 108.7W 65 KT 75 MPH
36H 04/1800Z 17.2N 109.6W 60 KT 70 MPH
48H 05/0600Z 17.2N 110.7W 55 KT 65 MPH
72H 06/0600Z 17.5N 113.0W 50 KT 60 MPH
96H 07/0600Z 18.0N 115.0W 40 KT 45 MPH
120H 08/0600Z 18.5N 117.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
$$
FORECASTER BEVEN
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