WTNT44 KNHC 281502 RRA

TCDAT4



TROPICAL STORM MATTHEW DISCUSSION NUMBER   1

NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142016

1100 AM AST WED SEP 28 2016



SURFACE OBSERVATIONS AND DATA FROM AN AIR FORCE RESERVE

RECONNAISSANCE AIRCRAFT INDICATE THAT THE TROPICAL WAVE PASSING

THROUGH THE WINDWARD ISLANDS HAS ACQUIRED A CLOSED CIRCULATION.  THE

AIRCRAFT FOUND PEAK FLIGHT-LEVEL WINDS OF 64 KT, AND SFMR SURFACE

WINDS OF AROUND 50 KT OVER THE NORTHERN PORTION OF THE CIRCULATION.

AS A RESULT, ADVISORIES ARE BEING INITIATED ON A 50-KT TROPICAL

STORM. THE CURRENT LACK OF INNER CORE STRUCTURE SUGGESTS THAT

FURTHER STRENGTHENING SHOULD BE LIMITED TODAY, BUT ENVIRONMENTAL

CONDITIONS CONSISTING OF WARM WATER AND LOW SHEAR AHEAD OF MATTHEW

FAVOR INTENSIFICATION THROUGHOUT THE REMAINDER OF THE FORECAST

PERIOD. THE NHC INTENSITY FORECAST IS MORE CONSERVATIVE THAN THE

STATISTICAL GUIDANCE, BUT FOLLOWS THE TRENDS OF THE GLOBAL MODELS

IN DEEPENING THE SYSTEM.



SINCE THE CENTER HAS VERY RECENTLY FORMED, THE INITIAL MOTION

ESTIMATE IS A HIGHLY UNCERTAIN 275/18 KT.  A STRONG DEEP-LAYER RIDGE

OVER THE WESTERN ATLANTIC SHOULD STEER MATTHEW WESTWARD ACROSS THE

EASTERN CARIBBEAN DURING THE NEXT FEW DAYS, AND THE TRACK GUIDANCE

IS TIGHTLY CLUSTERED THROUGH 72 HOURS.  AFTER THAT TIME, THE

TROPICAL CYCLONE WILL BE APPROACHING THE WESTERN PORTION OF THE

RIDGE AND A NORTHWESTWARD TURN IS EXPECTED, ALTHOUGH THERE ARE

SIGNIFICANT DIFFERENCES AMONG THE TRACK MODELS AS TO WHEN THE TURN

TAKES PLACE AND HOW SHARP IT WILL BE.  THE GFS TAKES THE CYCLONE

NORTHWESTWARD MUCH FASTER THAN THE ECMWF WITH MORE TROUGHING

DEVELOPING OVER THE EASTERN GULF OF MEXICO.  FOR NOW, THE NHC TRACK=