WTPZ45 KNHC 060840 RRA

TCDEP5



TROPICAL STORM IVETTE DISCUSSION NUMBER  15

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP102016

200 AM PDT SAT AUG 06 2016



IVETTE IS FEELING THE EFFECTS OF 10-15 KT OF SOUTHWESTERLY VERTICAL

SHEAR AND DRY AIR ENTRAINMENT, AS CONVENTIONAL AND MICROWAVE

SATELLITE IMAGERY INDICATE THAT THE LOW-LEVEL CENTER IS NOW

DISPLACED TO THE SOUTHWEST OF THE CONVECTION.  THE INITIAL

INTENSITY REMAINS 50 KT IN AGREEMENT WITH VARIOUS SUBJECTIVE AND

OBJECTIVE SATELLITE INTENSITY ESTIMATES.  HOWEVER, THIS COULD BE A

LITTLE GENEROUS.



THE INITIAL MOTION IS 280/9, AS THE STORM CONTINUES TO BE STEERED BY

THE SUBTROPICAL RIDGE TO ITS NORTH.  IVETTE SHOULD TURN TOWARD THE

WEST-NORTHWESTWARD SHORTLY, AS IT NEARS THE WESTERN PERIPHERY OF THE

RIDGE.  HOWEVER, IN ABOUT THREE DAYS, THE TROPICAL CYCLONE SHOULD

TURN WESTWARD AS THE WEAKENING SYSTEM IS STEERED BY THE LOW-LEVEL

EASTERLY TRADE WINDS.  THE NEW TRACK FORECAST IS LITTLE CHANGED FROM

THE PREVIOUS FORECAST AND LIES NEAR THE TVCN CONSENSUS MODEL.



ALTHOUGH IVETTE IS EXPECTED TO REMAIN OVER 26C-28C SEA SURFACE

TEMPERATURES DURING THE FORECAST PERIOD, THE COMBINATION OF

INCREASING SHEAR AND ABUNDANT DRY AIR SEEN IN WATER VAPOR IMAGERY

ARE EXPECTED TO CAUSE THE STORM TO WEAKEN.  THE INTENSITY FORECAST

NO LONGER SHOWS ANY INTENSIFICATION.  INSTEAD, THE INITIAL

INTENSITY IS MAINTAINED THROUGH 24 HOURS IN GENERAL AGREEMENT WITH

THE INTENSITY GUIDANCE, FOLLOWED BY A SLOW WEAKENING TREND.  THE

DYNAMICAL MODELS ARE IN GOOD AGREEMENT THAT IVETTE WILL WEAKEN TO A

TROUGH BY 120 HOURS, SO THE FORECAST CALLS FOR THE CYCLONE TO

DISSIPATE BY THAT TIME.





FORECAST POSITIONS AND MAX WINDS=