000
WTPZ42 KNHC 232040
TCDEP2
TROPICAL STORM DALILA DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP072007
200 PM PDT MON JUL 23 2007
 
CONVENTIONAL AND MICROWAVE IMAGERY DEPICT A TROPICAL CYCLONE THAT
CONTINUES TO STRUGGLE WITHIN A 20 TO 25 KT VERTICAL SHEAR
ENVIRONMENT.  THE RATHER DISORGANIZED CIRCULATION CENTER IS EXPOSED
APPROXIMATELY 35 NM NORTHEAST OF THE DEEP CONVECTION....AND TO THE
WEST OF LINE OF DEEP CONVECTION SITUATED JUST OFF THE COAST OF
SOUTHWESTERN MEXICO. DVORAK SATELLITE INTENSITY ESTIMATES ARE 30 KT
FROM SAB AND 35 KT FROM TAFB...WITH THE INITIAL INTENSITY SET AT A
GENEROUS 35 KT.
 
DYNAMICAL MODELS CONTINUE TO SUGGEST THAT THE NORTHEASTERLY SHEAR
OVER THE SYSTEM WILL WEAKEN DURING THE NEXT 24 HOURS...ALLOWING THE
CYCLONE TO GRADUALLY INTENSIFY.  BEYOND 72 HOURS...DALILA IS
EXPECTED TO MOVE OVER LOWER SEA SURFACE TEMPERATURES THAT SHOULD
INDUCE A WEAKENING TREND THROUGH THE REMAINING PORTION OF THE
FORECAST.  THE INTENSITY FORECAST FOLLOWS A BLEND OF THE
SHIPS...GFDL...LGEM...AND THE HWRF...WHICH INDICATE A PEAK INTENSITY
OF 55 KT BY DAY 3...BEFORE A WEAKENING TREND COMMENCES.
 
THE INITIAL MOTION IS ESTIMATED AT 325/7...SLIGHTLY TO THE RIGHT OF
THE PREVIOUS MOTION. THE FORECAST TRACK PHILOSOPHY REMAINS
UNCHANGED...WITH DALILA'S MOTION INFLUENCED BY A WEAK
MID-TROPOSPHERIC RIDGE TO THE NORTH...EXTENDING WEST-SOUTHWESTWARD
FROM THE SOUTHWEST UNITED STATES. THE ECMWF AND THE GFDN CONTINUE
TO SUGGEST A STRONGER INFLUENCE FROM THE DEVELOPING WEAKNESS OVER
CENTRAL MEXICO...WITH A MORE NORTHWARD MOTION THAN THE OTHER MODELS
AROUND MID-PERIOD. THE OFFICIAL FORECAST IS BASED ON A CONSENSUS OF
THE AVAILABLE DYNAMICAL MODELS AND THE SUPERENSEMBLE...WITH LESS
EMPHASIS ON THE TWO AFOREMENTIONED MODELS.
 
THE WIND RADII HAVE BEEN ADJUSTED BASED ON THE 1312Z QUIKSCAT
OVERPASS.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/2100Z 15.4N 109.2W    35 KT
 12HR VT     24/0600Z 16.1N 109.9W    35 KT
 24HR VT     24/1800Z 17.2N 110.7W    40 KT
 36HR VT     25/0600Z 18.0N 111.4W    45 KT
 48HR VT     25/1800Z 18.8N 112.1W    50 KT
 72HR VT     26/1800Z 20.5N 114.0W    55 KT
 96HR VT     27/1800Z 22.3N 116.3W    45 KT
120HR VT     28/1800Z 24.0N 119.0W    30 KT
 
$$
FORECASTER ROBERTS/BEVEN