WTPZ44 KNHC 280853 RRA

TCDEP4



HURRICANE ULIKA DISCUSSION NUMBER   8

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP192016

200 AM PDT WED SEP 28 2016



ULIKA HAS CONTINUED TO IMPROVE IN ORGANIZATION, AND RECENT MICROWAVE

DATA HAVE SHOWN THAT THE CYCLONE HAS MAINTAINED A WELL-DEFINED EYE

IN THE 89-GHZ CHANNEL DURING THE PAST FEW HOURS.  HINTS OF AN EYE

HAVE ALSO BEEN OBSERVED IN SHORTWAVE INFRARED IMAGERY, EMBEDDED

WITHIN A COMPACT CENTRAL DENSE OVERCAST.  SUBJECTIVE SATELLITE

INTENSITY ESTIMATES HAVE RISEN TO T4.0/65 KT FROM TAFB AND T3.0/55

KT FROM SAB, AND THE OBJECTIVE ADT FROM UW-CIMSS IS EVEN HIGHER

AROUND 75 KT.  A COUPLE OF CIMSS AMSU INTENSITY ESTIMATES ALSO

PROVIDED VALUES OF 60-65 KT SEVERAL HOURS AGO.  BASED ON THESE

DATA, ULIKA IS UPGRADED TO A HURRICANE WITH 65-KT WINDS, AND THIS

COULD BE CONSERVATIVE.



ULIKA HAS RAPIDLY INTENSIFIED DURING THE PAST 24 HOURS, WHICH IN

HINDSIGHT WAS PROBABLY HELPED BY THE CYCLONE'S SMALL WIND FIELD AND

RADIUS OF MAXIMUM WINDS.  VERTICAL SHEAR IS EXPECTED TO REMAIN LOW

FOR ANOTHER 12 HOURS OR SO, WHICH COULD ALLOW ULIKA TO INTENSIFY

SOME MORE IN THE SHORT TERM.  BY 24 HOURS, HOWEVER, SOUTHWESTERLY

TO WESTERLY VERTICAL SHEAR IS FORECAST TO INCREASE MARKEDLY,

EXCEEDING 30 KT IN A COUPLE OF DAYS.  GIVEN ULIKA'S SMALL SIZE, THE

CYCLONE WILL BE PARTICULARLY SENSITIVE TO THE INCREASE IN SHEAR,

AND ITS INTENSITY IS LIKELY TO DECREASE QUICKLY.  ULIKA IS EXPECTED

TO BECOME A REMNANT LOW BY DAY 4 AND THEN DISSIPATE SOUTHEAST OF

THE HAWAIIAN ISLANDS BY DAY 5.  THE NHC INTENSITY FORECAST IS VERY

CLOSE TO THE INTENSITY CONSENSUS FOR THE ENTIRE FORECAST PERIOD, AND

IS HIGHER THAN THE PREVIOUS FORECAST DURING THE FIRST 36 HOURS TO=