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TROPICAL STORM DALILA DISCUSSION NUMBER   8
NATIONAL WEATHER SERVICE MIAMI FL
2 PM PDT SUN JUL 22 2001
 
EVEN WITH VISIBLE IMAGERY...THE CENTER OF DALILA IS NOT OBVIOUS.  IT
IS BELIEVED TO BE IN THE NORTHEAST PART OF THE DENSE OVERCAST.
LATEST DVORAK ESTIMATES GIVE NO CHANGE IN INTENSITY...ALTHOUGH
RECENT IMAGES SUGGEST SOME SLIGHT EVIDENCE OF BANDING FEATURES
DEVELOPING.  UPPER-LEVEL OUTFLOW IS WEAK OVER THE EASTERN
SEMICIRCLE...AND THERE IS STILL EVIDENCE OF EASTERLY SHEAR OVER THE
SYSTEM.  THE SHIPS GUIDANCE CONTINUES TO CALL FOR STRENGTHENING.
HOWEVER...CONSIDERING THAT THE STORM HAS FAILED TO STRENGTHEN
SIGNIFICANTLY TODAY...I HAVE BACKED OFF JUST SLIGHTLY ON THE
OFFICIAL INTENSITY FORECAST.  NEAR THE END OF THE PERIOD...THE
CYCLONE SHOULD BE PASSING OVER MARGINAL SSTS SO GRADUAL WEAKENING IS
LIKELY TO COMMENCE BY THAT TIME.
 
INITIAL MOTION IS ABOUT THE SAME AS BEFORE...300/13.  THERE IS NOT
MUCH CHANGE TO THE FORECAST PHILOSOPHY.  THE NCEP...U.K. MET
OFFICE...AND NAVY GLOBAL MODELS ALL SHOW A 500 MB RIDGE TO THE NORTH
OF DALILA OVER THE NEXT FEW DAYS.  THEREFORE A CONTINUED
WEST-NORTHWEST TRACK IS FORECAST.  THE GFDL MODEL HAS BEEN THE
OUTLIER...AND IT SHOWS A TURN TO THE NORTH-NORTHWEST.  BASED ON THE
STEERING FLOW SHOWN BY THE LARGE-SCALE MODELS...SUCH A TRACK DOES
NOT SEEM REASONABLE.
 
FORECASTER PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     22/2100Z 16.1N 102.6W    60 KTS
12HR VT     23/0600Z 16.6N 104.0W    65 KTS
24HR VT     23/1800Z 17.5N 106.0W    70 KTS
36HR VT     24/0600Z 18.0N 107.5W    80 KTS
48HR VT     24/1800Z 18.5N 109.0W    80 KTS
72HR VT     25/1800Z 19.5N 112.0W    75 KTS
 
 
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