WTPZ44 KNHC 281438 RRA

TCDEP4



TROPICAL STORM HILARY DISCUSSION NUMBER  29

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP092017

800 AM PDT FRI JUL 28 2017



CLOUD TOPS NEAR THE CENTER OF HILARY CONTINUE TO WARM THIS MORNING,

AND A CONSENSUS OF OBJECTIVE AND SUBJECTIVE DVORAK INTENSITY

ESTIMATES SUGGESTS A DECREASED INITIAL INTENSITY OF 55 KT.  AN AMSR

PASS AT 0913 UTC SHOWED A BAND OF DEEP CONVECTION SPIRALING INTO THE

CENTER.  THERE IS ALSO A PRONOUNCED DRY SLOT, INDICATIVE OF THE

DRIER ENVIRONMENT THAT THE CYCLONE IS MOVING INTO.  HILARY IS

CROSSING THE 26 C SST ISOTHERM THIS MORNING, SO THE WINDOW FOR ANY

REINTENSIFICATION IS CLOSING QUICKLY, DESPITE THE INSISTENCE OF THE

HWRF AND GFS WHICH BOTH SHOW A HURRICANE IN 24 HOURS.  INSTEAD, THE

OFFICIAL FORECAST CONTINUES TO FOLLOW THE STATISTICAL MODELS, WHICH

DEPICT STEADY WEAKENING UNTIL HILARY BECOMES A REMNANT LOW.  THE

INTENSITY FORECAST IS A LITTLE LOWER THAN INDICATED IN THE PREVIOUS

ADVISORY BASED ON THE LOWER INITIAL INTENSITY, BUT NO SIGNIFICANT

CHANGES HAVE BEEN MADE.



THE LOW-LEVEL CENTER OF THE TROPICAL STORM WAS BRIEFLY VISIBLE THIS

MORNING, AND THE INITIAL MOTION IS A FAIRLY CONFIDENT 305/7.  THERE

HAS BEEN A SIGNIFICANT SHIFT IN THE GUIDANCE TOWARD THE NORTH FOR

THIS ADVISORY, ESPECIALLY THE GFS AND THE GFS-BASED HURRICANE

MODELS. THE 06Z GFS IN PARTICULAR HAS SHIFTED NEARLY 500 NM TO THE

NORTHEAST AT DAY 5 AND NO LONGER SHOWS ANY SIGNIFICANT INTERACTION

BETWEEN IRWIN AND HILARY. THE 00Z ECMWF ALSO SHIFTED A LITTLE NORTH,

BUT NOT NEARLY TO THE SAME EXTENT.  INTERACTION BETWEEN THE

TWO CYCLONES, AND THE EVENTUAL ABSORPTION OF IRWIN BY HILARY, IS