Tropical Storm DALILA
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TROPICAL STORM DALILA DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL EP042013
800 AM PDT MON JUL 01 2013
A 0949 UTC TRMM PASS SHOWED THAT THE INNER CORE OF DALILA HAS BECOME
A LITTLE BETTER ORGANIZED...AND A RAINBAND NOW WRAPS MOST OF THE
WAY AROUND THE CENTER. DVORAK INTENSITY ESTIMATES FROM ALL
AGENCIES HAVE INCREASED...AND SUPPORT INCREASING THE INITIAL
INTENSITY TO 50 KT. ALTHOUGH THE CYCLONE IS LOCATED WITHIN A
SYNOPTIC ENVIRONMENT THAT SHOULD SUPPORT INTENSIFICATION OVER THE
NEXT DAY OR SO...MOST OF THE MODEL GUIDANCE SUGGESTS ONLY SLIGHT
INTENSIFICATION WILL OCCUR. THE OFFICIAL FORECAST REMAINS ON THE
UPPER END OF THE GUIDANCE ENVELOPE FOR THE FIRST 36 HOURS...AND
DALILA IS STILL EXPECTED TO REACH HURRICANE INTENSITY. AFTER
THAT...THE GLOBAL MODELS...PARTICULARLY THE ECMWF...SUGGEST THAT
DALILA WILL ENCOUNTER A LAYER OF MID- TO UPPER-LEVEL DRY AIR...WHICH
SHOULD CAUSE THE CYCLONE TO WEAKEN STEADILY.
MICROWAVE AND IR-BASED CENTER FIXES INDICATE THAT DALILA CONTINUES
TO MOVE TOWARD THE NORTHWEST WITH AN ESTIMATED MOTION OF 310/8. A
TURN TOWARD THE WEST-NORTHWEST WITH A DECREASE IN FORWARD SPEED IS
EXPECTED AS THE CYCLONE IS STEERED BY A STRONG DEEP-LAYER RIDGE TO
THE NORTH. THERE IS A LARGE AMOUNT OF SPREAD IN THE MODEL
GUIDANCE...ESPECIALLY AFTER TWO DAYS...EXEMPLIFIED BY THE GFS AND
ECMWF FORECASTS. THE GFS IS FORECASTING A DEEPER VORTEX WHICH
MOVES FARTHER NORTH...WHILE THE ECMWF FORECASTS A SHALLOW VORTEX
MOVING SLOWLY TOWARD THE SOUTHWEST. THE OFFICIAL FORECAST...IN LINE
WITH THE INTENSITY FORECAST...SPLITS THESE TWO SCENARIOS AND CALLS
FOR A STEADY WESTWARD MOTION AFTER 48 HOURS.
FORECAST POSITIONS AND MAX WINDS
INIT 01/1500Z 17.8N 105.8W 50 KT 60 MPH
12H 02/0000Z 18.2N 106.5W 55 KT 65 MPH
24H 02/1200Z 18.6N 107.3W 65 KT 75 MPH
36H 03/0000Z 18.8N 107.9W 60 KT 70 MPH
48H 03/1200Z 18.9N 108.6W 55 KT 65 MPH
72H 04/1200Z 19.0N 109.5W 50 KT 60 MPH
96H 05/1200Z 19.0N 111.5W 45 KT 50 MPH
120H 06/1200Z 19.0N 114.0W 35 KT 40 MPH
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FORECASTER PASCH/ZELINSKY
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