ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM DALILA DISCUSSION NUMBER 9
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT SUN JUL 22 2001
CONVECTIVE BANDING HAS DECREASED AND TYHE CENTRAL DEEP CONVECTION
HAS BECOME ELONGATED NORTHEAST-SOUTHWEST DUE TO UPPER-LEVEL
NORTHEASTERLY SHEAR. OUTFLOW IS FAIR TO GOOD IN THE WESTERN
SEMICIRCLE AND RESTRICTED TO THE EAST. THE INITIAL INTENSITY WAS
HELD AT 60 KT BASED ON DVORAK SATELLITE INTENSITY ESTIMATES OF 55
KT...T3.5...FROM TAFB AND SAB.
INITIAL MOTION ESTIMATE IS 300/14. THE PREVIOUS FORECAST HAD A GOOD
HANDLE ON THE FORECAST TRACK OF DALILA BY DISCOUNTING THE GFDL MODEL
AND ITS NORTHWARD TRACK INTO THE GULF OF CALIFORNIA. THE LATEST GFDL
RUN IS NO LONGER AN OUTLIER AND IS IN THE MIDDLE OF THE REMAINING
MODEL SUITE. ALL OF THE MODEL GUIDANCE GENERALLY AGREE ON A
WEST-NORTHWEST TO WESTWARD TRACK THROUGH THE PERIOD AS THE SYSTEM
MOVES ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE TO THE
NORTH. THE OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS TRACK AND THE
UKMET MODEL.
THE INTENSITY FORECAST IS NOT AS STRAIGHT-FORWARD AS THE TRACK
FORECAST. NORTHEASTERLY SHEAR IS DISRUPTING THE CENTRAL DEEP
CONVECTION AND DALILA MAY NOT BE AS STRONG AS INDICATED. THE SHIPS
AND AVN MODELS ARE FORECASTING THE SHEAR TO GRADUALLY DECREASE AND
BRING DALILA TO HURRICANE STRENGTH IN 12 HOURS. THE PREVIOUS
FORECAST TREND WAS MAINTAINED IN CASE A BURST OF DEEP CONVECTION
FIRES OFF LATER TONIGHT.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 23/0300Z 16.5N 103.7W 60 KTS
12HR VT 23/1200Z 17.3N 105.4W 65 KTS
24HR VT 24/0000Z 17.9N 107.1W 70 KTS
36HR VT 24/1200Z 18.5N 108.6W 80 KTS
48HR VT 25/0000Z 18.9N 110.1W 80 KTS
72HR VT 26/0000Z 20.0N 113.0W 75 KTS
NNNN
Problems?