WTPZ44 KNHC 230849 RRA

TCDEP4



TROPICAL STORM HILARY DISCUSSION NUMBER   8

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092017

400 AM CDT SUN JUL 23 2017



THE CLOUD PATTERN OF HILARY IS GRADUALLY BECOMING BETTER ORGANIZED,

WITH SOME CONVECTIVE BANDING FEATURES BEGINNING TO DEVELOP.  THE

UPPER-LEVEL OUTFLOW IS WELL DEFINED OVER ALL BUT THE SOUTHEASTERN

SEMICIRCLE OF THE CIRCULATION.  DVORAK T-NUMBERS FROM TAFB AND SAB

REMAIN AT 2.5 SO THE CURRENT INTENSITY IS HELD AT 35 KT.  THIS IS

ALSO CONSISTENT WITH ASCAT DATA FROM A FEW HOURS AGO.  THE

ATMOSPHERIC AND OCEANIC ENVIRONMENT SHOULD BE QUITE FAVORABLE FOR

INTENSIFICATION DURING THE NEXT FEW DAYS.  THE SHIPS GUIDANCE

INDICATES THAT THE VERTICAL SHEAR SHOULD REMAIN BELOW 10 KT

THROUGHOUT THE FORECAST PERIOD, AND THE GLOBAL MODELS SHOW A LARGE

UPPER-LEVEL ANTICYCLONE OVER HILARY THROUGH 4-5 DAYS.  LATE IN THE

PERIOD HILARY IS EXPECTED TO MOVE OVER COOLER SSTS, AND THIS SHOULD

HALT THE INTENSIFICATION PROCESS.  THE OFFICIAL INTENSITY FORECAST

SHOWS THE SYSTEM APPROACHING MAJOR HURRICANE STATUS IN 72 HOURS

AND SOME OF THE GUIDANCE, INCLUDING THE CORRECTED CONSENSUS MODELS,

SUGGEST THAT THIS COULD BE CONSERVATIVE.



OVERNIGHT MICROWAVE DATA INDICATE A BIT OF A JUMP TO THE

WEST-NORTHWEST, PERHAPS AS A RESULT OF REFORMATION OF THE CENTER AS

OPPOSED TO LARGE-SCALE MOTION.  THE INITIAL MOTION ESTIMATE IS

300/13 KT.  A LARGE MID-LEVEL ANTICYCLONE CENTERED OVER THE

SOUTHWESTERN UNITED STATES OR NORTHWESTERN MEXICO SHOULD MAINTAIN

THE WEST-NORTHWESTWARD HEADING THROUGHOUT THE FORECAST PERIOD.  THE

TRACK MODEL GUIDANCE IS IN AGREEMENT ON A DECREASE IN FORWARD SPEED,