WTNT44 KNHC 010847 RRA

TCDAT4



HURRICANE MATTHEW DISCUSSION NUMBER  13

NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142016

500 AM EDT SAT OCT 01 2016



MATTHEW HAS CHANGED LITTLE IN ORGANIZATION SINCE THE PAST ADVISORY,

WITH A SMALL EYE SURROUNDED BY A CENTRAL DENSE OVERCAST FEATURING

CLOUD TOPS COLDER THAN -80C.  THE EYE HAS BECOME A LITTLE LESS

DISTINCT, SUGGESTING AT LEAST THAT THE HURRICANE IS NO LONGER

INTENSIFYING.  IN ADDITION, THE RAW INTENSITY ESTIMATES FROM THE

CIMSS ADT TECHNIQUE ARE SLIGHTLY LOWER THAN THEY WERE SIX HOURS

AGO.  BASED ON THESE TRENDS, THE INITIAL INTENSITY IS REDUCED TO

135 KT. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS SCHEDULED

TO REACH MATTHEW NEAR 1200 UTC.



THE INITIAL MOTION IS NOW 270/6.  MATTHEW REMAINS SOUTH OF A LOW-

TO MID-LEVEL RIDGE OVER THE WESTERN ATLANTIC.  THE DYNAMICAL MODELS

FORECAST THIS RIDGE TO WEAKEN OVER THE NEXT 72 HOURS AS A MID- TO

UPPER-LEVEL TROUGH DEVELOPS OVER THE GULF OF MEXICO.  THIS

EVOLUTION SHOULD CAUSE MATTHEW TO TURN NORTHWESTWARD AFTER 24 HOURS

AND NORTHWARD BY 48-72 HOURS.  THE GUIDANCE GENERALLY AGREES WITH

THIS SCENARIO.  HOWEVER, THERE IS A SPREAD BETWEEN THE GFS FORECAST

OF LANDFALL IN JAMAICA AND EASTERN CUBA AND THE ECMWF FORECAST

LANDFALL IN SOUTHWESTERN HAITI.  THE GUIDANCE BECOMES MORE DIVERGENT

AFTER 72 HOURS.  THE GFS SHOWS A TURN TOWARD THE NORTH-NORTHWEST,

WHICH BRINGS THE CENTER CLOSER TO THE NORTHWESTERN BAHAMAS AND

FLORIDA. THIS MODEL IS NEAR THE WESTERN EDGE OF THE GUIDANCE

ENVELOPE.  THE ECMWF IS NEAR THE EASTERN EDGE OF THE GUIDANCE

ENVELOPE AND SHOWS THE CENTER EAST OF THE BAHAMAS BY 120 HOURS.

ADDING TO THE UNCERTAINTY IS THE EASTWARD SHIFT OF THE CANADIAN=