WTPZ45 KNHC 191443 RRA

TCDEP5



TROPICAL STORM DARBY DISCUSSION NUMBER  32

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP052016

800 AM PDT TUE JUL 19 2016



CONVENTIONAL SATELLITE IMAGERY SHOWS THAT THE INNER CORE CLOUD TOPS

HAVE WARMED SINCE LAST NIGHT AND DEEP CONVECTIVE BANDING HAS BECOME

FRAGMENTED.  ALTHOUGH DARBY HAS EXHIBITED AN INTERMITTENT RAGGED EYE

FEATURE, A BLEND OF THE SUBJECTIVE FINAL-T AND CI-NUMBERS, AND

THE OBJECTIVE ADT ESTIMATE, YIELD AN INTENSITY OF 60 KT.

ADDITIONALLY, THE AMBIGUITY SOLUTION OF AN EARLIER ASCAT OVERPASS

REVEALED ONLY A COUPLE OF 50-55 KT WINDS OVER THE NORTHERN QUADRANT.

ACCORDINGLY, DARBY'S INITIAL INTENSITY HAS BEEN LOWERED TO 60 KT FOR

THIS ADVISORY.  THE CYCLONE IS CURRENTLY TRAVERSING SUB-25C WATER,

BUT SHOULD BE MOVING BACK OVER SLIGHTLY WARMER WATER EAST OF

THE HAWAIIAN ISLANDS NEAR THE 36 HOUR PERIOD.  DARBY, HOWEVER, WILL

ALSO BE MOVING INTO A MORE STABLE THERMODYNAMIC ENVIRONMENT AND

MODEST SOUTHWESTERLY SHEAR AROUND THE SAME TIME.  THEREFORE, THESE

CONTRIBUTING FACTORS ARE EXPECTED TO CAUSE DARBY TO GRADUALLY WEAKEN

THROUGH THE PERIOD.  THE OFFICIAL INTENSITY FORECAST IS BASED

PRIMARILY ON THE MODEL CONSENSUS, IVCN, WHICH INCLUDES THE HWRF

HURRICANE MODEL, AND IS ABOVE BOTH THE SHIPS AND LGEM

STATISTICAL-DYNAMICAL INTENSITY MODELS.



THE TRACK FORECAST PHILOSOPHY REMAINS SIMILAR TO THE PREVIOUS

FORECAST.  THE CYCLONE SHOULD CONTINUE ON A GENERALLY WESTWARD

HEADING TO THE SOUTH OF A MID-TROPOSPHERIC RIDGE ANCHORED ALONG 30N

FOR THE NEXT FEW DAYS.  AT THE 96 HOUR PERIOD, DARBY IS FORECAST

TO SLOW ITS FORWARD SPEED AS IT ENCOUNTERS A GROWING WEAKNESS IN THE

RIDGE WHILE A MID- TO UPPER-LEVEL LOW DIGS NORTH OF THE HAWAIIAN=