ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM HURRICANE DARBY DISCUSSION NUMBER 15 NATIONAL WEATHER SERVICE MIAMI FL 2 PM PDT SUN JUL 26 1998 THE INITIAL MOTION ESTIMATE IS 275/12. THE AVIATION MODEL 12Z RUN...LIKE THE 00Z RUN...SHOWS A CUT-OFF 500 MB LOW TO THE NORTH-NORTHWEST OF THE HURRICANE. IT ALSO SHOWS A RIDGE BUILDING JUST NORTH OF THE HURRICANE THROUGH 72 HOURS SUCH THAT THE TRACK SHOULD REMAIN ON A WEST TO WEST-NORTHWESTWARD TRACK. THE TRACK GUIDANCE MODELS ALL SHOWS A WEST TO WEST-NORTHWESTWARD TRACK THROUGH 72 HOURS EXCEPT THE AVIATION MODEL WHICH IS WEST-SOUTHWESTWARD. THE OFFICIAL FORECAST IS WITH THE GUIDANCE AND ESPECIALLY CLOSE TO THE GFDL AND UKMET WHICH ARE WITHIN 25 NMI OF EACH OTHER AT 72 HOURS. A WELL-DEFINED EYE CONTINUES TO PERSIST AND DVORAK ESTIMATES INCREASE THE WIND SPEED TO 100 KNOTS AGAIN. THE FORECAST TRACK IS ALMOST PARALLEL TO THE SST ISOPLETHS SO THAT WEAKENING MAY BE SLOW AND IS SLOWED DOWN SOME FROM THE PREVIOUS ADVISORY. LAWRENCE FORECAST POSITIONS AND MAX WINDS INITIAL 26/2100Z 16.3N 127.2W 100 KTS 12HR VT 27/0600Z 16.5N 129.0W 100 KTS 24HR VT 27/1800Z 16.7N 131.5W 90 KTS 36HR VT 28/0600Z 17.1N 134.5W 80 KTS 48HR VT 28/1800Z 17.5N 137.5W 70 KTS 72HR VT 29/1800Z 19.0N 143.5W 50 KTS NNNN