WTNT45 KNHC 180258 RRA

TCDAT5



TROPICAL STORM NICOLE DISCUSSION NUMBER  56

NWS NATIONAL HURRICANE CENTER MIAMI FL       AL152016

1100 PM AST MON OCT 17 2016



THE OLD ADAGE ABOUT TROPICAL CYCLONES TRANSITIONING TO EXTRATROPICAL

ONCE THE LATITUDE IS LARGER THAN THE LONGITUDE DOES NOT APPLY TO

NICOLE.  THE SYSTEM HAS BEEN ABLE TO MAINTAIN A COHERENT INNER CORE

OF DEEP CONVECTION, WHICH WRAPS ABOUT TWO-THIRDS THE WAY AROUND ITS

CENTER.  THIS IS, HOWEVER, SOMEWHAT REDUCED FROM EARLIER TODAY AND

THE DVORAK DATA-T NUMBERS FROM TAFB AND SAB HAVE DROPPED. A JUST

ARRIVING ASCAT-A SCATTEROMETER PASS FROM 0019Z INDICATES THAT PEAK

WINDS ARE ABOUT 60 KT AND THIS MAY BE A BIT GENEROUS. THUS NICOLE

HAS WEAKENED TO A TROPICAL STORM.



NICOLE'S RESILIENCE AS A TROPICAL CYCLONE IS LIKELY DUE TO IT BEING

EMBEDDED WITHIN VERY LOW VERTICAL SHEAR AND IN QUITE COLD UPPER

TROPOSPHERIC TEMPERATURES, DESPITE THE SSTS DROPPING TO NEAR 20 DEG

C.  HOWEVER, NICOLE SHOULD SOON TRANSITION TO AN EXTRATROPICAL

CYCLONE, AS FRONTAL BOUNDARIES DEVELOP NEAR THE CENTER OF THE SYSTEM

BY TOMORROW.  EVEN THOUGH IT WILL BECOME EXTRATROPICAL, IT IS

ANTICIPATED THAT NICOLE WILL REMAIN A LARGE AND POWERFUL SYSTEM FOR

THE NEXT COUPLE OF DAYS BEFORE BEING ABSORBED BY A SEPARATE

EXTRATROPICAL CYCLONE IN ABOUT THREE DAYS. THE INTENSITY FORECAST IS

SLIGHTLY LESS THAN THAT FROM THE PREVIOUS ADVISORY BECAUSE OF THE

LOWERED INITIAL INTENSITY AND IS BASED UPON A DETERMINISTIC GLOBAL

MODEL CONSENSUS.



NICOLE IS MOVING TOWARD THE NORTHEAST AT ABOUT 22 KT, AS IT IS BEING

ADVECTED ALONG IN THE DEEP LAYER SOUTHWESTERLY FLOW AHEAD OF A

SHORTWAVE TROUGH OVER EASTERN CANADA.  A 2019Z AMSU PASS AND THE=