Tropical Storm DALILA

ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM DALILA DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP072007
800 AM PDT TUE JUL 24 2007
 
LATEST CONVENTIONAL SATELLITE IMAGERY INDICATES THAT DALILA IS
CONTINUING TO SLOWLY STRENGTHEN.  MOST OF THE DEEP CONVECTION IS
LOCATED OVER THE SOUTHERN SEMICIRCLE...WHILE SOME CONVECTION
LOCATED TO THE NORTH OF THE CENTER HAS STARTED TO SHOW SIGNS OF
WEAKENING.  THE CURRENT INTENSITY REMAINS AT 40 KT IN LINE WITH A
CONSENSUS OF THE SUBJECTIVE DVORAK ESTIMATES FROM TAFB AND SAB.
 
EXCEPT FOR AN ADJUSTMENT MADE TO THE INITIAL MOTION OF DALILA BASED
ON A 0922 UTC AQUA SATELLITE PASS WHICH SHOWED THE LOW LEVEL CENTER
A BIT TO THE WEST OF PREVIOUS ESTIMATES...LITTLE CHANGE WAS MADE TO
THE PREVIOUS FORECAST PHILOSOPHY.  

WATER VAPOR IMAGERY SHOWS A TROUGH TO THE NORTH OF DALILA...WHICH
HAS ALLOWED THE STORM TO MOVE NORTH-NORTHWEST. THE GLOBAL MODELS
SHOW THAT THE TROUGH WILL MOVE TO THE NORTH OF DALILA...WHICH
ALLOWS THE STORM TO TAKE ON A MORE WESTERLY PATH WITH TIME. THE
GLOBAL MODELS DIFFER ON HOW FAR WEST DALILA WILL GO. THE ECMWF AND
CANADIAN SHOW THE STORM TAKING A MORE NORTHERLY PATH AS EACH OF
THOSE MODELS ALLOW DALILA TO MOVE INTO A WEAKNESS IN THE HEIGHT
FIELD CAUSED BY A SECOND MID LEVEL TROUGH.  THE GFS...
HWRF...GDFL...UKMET AND NOGAPS SHOW LESS OF A WEAKNESS ALOFT AND
THEY TAKE DALILA ON A MORE WESTERLY COURSE.  GIVEN THE ANOMOLOUS
STRENGTH IN THE ECMWF/CANADIAN...AND GIVEN THE FACT THAT THE
GUIDANCE HAS SHOWN A TREND TO THE WEST OVER TIME...WE ARE FAVORING
THE MORE WESTERLY TRACK.
 
VERTICAL SHEAR IS STILL FORECAST TO DECREASE DURING THE NEXT
24-48 HOURS...BUT THE THERMODYNAMIC ENVIRONMENT DOES NOT APPEAR
IDEAL. ADDITIONALLY...DALILA WILL BEGIN TO ENCOUNTER COOLER WATERS
AFTER 48 HOURS.  THESE FACTORS SHOULD LIMIT SIGNIFICANT
STRENGTHENING IN THE SHORT-TERM AND ULTIMATELY RESULT IN WEAKENING
BEYOND 48 HOURS. INTENSITY GUIDANCE MODELS ARE LITTLE CHANGED AND
SO IS THE OFFICIAL FORECAST.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/1500Z 16.7N 110.6W    40 KT
 12HR VT     25/0000Z 17.5N 111.2W    45 KT
 24HR VT     25/1200Z 18.5N 111.9W    50 KT
 36HR VT     26/0000Z 19.3N 112.8W    50 KT
 48HR VT     26/1200Z 20.1N 113.8W    50 KT
 72HR VT     27/1200Z 21.6N 116.4W    45 KT
 96HR VT     28/1200Z 22.5N 119.3W    30 KT
120HR VT     29/1200Z 23.3N 122.0W    20 KT...DISSIPATING
 
$$
FORECASTER BANN
 
NNNN