WTPZ43 KNHC 082031 RRA

TCDEP3



TROPICAL STORM KRISTY DISCUSSION NUMBER   8

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP132018

200 PM PDT WED AUG 08 2018



KRISTY'S OVERALL STRUCTURE HASN'T CHANGED MUCH OVER THE PAST FEW

HOURS, BUT CLOUD TOPS ASSOCIATED WITH THE DEEPEST CONVECTION HAVE

NOTICEABLY WARMED. THE INTENSITY ESTIMATES FROM ALL AGENCIES HAVE

ALSO NOT CHANGED, SO THE INITIAL INTENSITY HAS BEEN HELD AT 40 KT.

UNFORTUNATELY, THE VARIOUS INTENSITY MODELS HAVE NOT CHANGED, EITHER

AND THE SPREAD REMAINS HIGH. WHILE THE HWRF CONTINUES TO SHOW KRISTY

QUICKLY STRENGTHENING TO HURRICANE INTENSITY, ALL OF THE

STATISTICAL-DYNAMICAL GUIDANCE KEEPS THE TROPICAL STORM VERY WEAK

THROUGHOUT THE FORECAST PERIOD. THE NHC FORECAST THEREFORE CONTINUES

TO SPLIT THE DIFFERENCE BETWEEN THESE SCENARIOS AND SHOWS SLOW

STRENGTHENING FOR A COUPLE OF DAYS WHILE THE CYCLONE REMAINS IN

A LOW-SHEAR ENVIRONMENT. BY DAYS 4 AND 5, KRISTY IS FORECAST TO BE

MOVING OVER MUCH COOLER SSTS AND THROUGH A MORE STABLE ENVIRONMENT,

WHICH SHOULD CAUSE IT TO WEAKEN AND BECOME A REMNANT LOW.



THE TRACK FORECAST IS ALSO STILL LOW CONFIDENCE. ALTHOUGH KRISTY IS

CURRENTLY MOVING WEST-NORTHWESTWARD WITH AN INITIAL MOTION OF 300/5

KT, THE MODELS ARE IN GOOD AGREEMENT THAT KRISTY WILL TURN NORTHWARD

OVERNIGHT AND TOMORROW DUE TO A WEAKNESS IN THE SUBTROPICAL RIDGE

CREATED BY HURRICANE JOHN. THE UNCERTAINTY GROWS SUBSTANTIALLY

BEYOND 24 H. THE GFS CONTINUES TO INSIST ON A STEERING FLOW THAT

WILL CAUSE KRISTY TO BECOME WRAPPED UP IN THE LARGER CIRCULATION OF

JOHN, WHILE THE UKMET AND ECMWF SHOW ONLY A SLOW NORTHWARD MOTION,

FOLLOWED BY A TURN BACK TOWARD THE WEST OR NORTHWEST ONCE THE