WTPZ42 KNHC 080858 RRA

TCDEP2



HURRICANE JOHN DISCUSSION NUMBER  11

NWS NATIONAL HURRICANE CENTER MIAMI FL       EP122018

300 AM MDT WED AUG 08 2018



AS MENTIONED IN THE PREVIOUS DISCUSSION, THE EYE OF JOHN PASSED

ABOUT 9 NMI NORTHEAST OF SOCORRO ISLAND AROUND 0030 UTC, WITH THE

ISLAND POSSIBLY BEING WITHIN OR JUST OUTSIDE THE EYEWALL. ADDITIONAL

DATA FROM AN AUTOMATED STATION ON THE ISLAND INDICATE THAT THE

HIGHEST SUSTAINED WIND REPORTED IN 15-MINUTE INTERVALS WAS 48 KT AT

0230 UTC, WITH ANOTHER 70-KT GUST REPORTED AT 0200 UTC. THE LOWEST

PRESSURE MEASURED WAS 970 MB AT 0015 UTC, WHICH IS PROBABLY A 4-5 MB

TOO LOW. SINCE THAT TIME, JOHN'S EYE HAS OCCASIONALLY BECOME

CLOUD-FILLED, BUT DEEP CONVECTION HAS RECENTLY DEVELOPED IN THE

EYEWALL. THE INITIAL INTENSITY IS ONLY DECREASED SLIGHTLY TO 85 KT

BASED ON A UW-CIMSS ADT ESTIMATE OF 87 KT AND DUE TO THE RECENT

UPTICK IN EYEWALL CONVECTION.



ALTHOUGH JOHN SHOULD REMAIN OVER WARM WATERS FOR ANOTHER 12 HOURS

OR SO, THE GENERAL TREND CALLS FOR STEADY WEAKENING DUE TO THE

INGESTION OF MORE STABLE AIR TO THE NORTH, WHICH IS EXPECTED TO

DECREASE THE INSTABILITY AND INNER-CORE CONVECTION. THE OFFICIAL

INTENSITY FORECAST IS LOWER THAN THE PREVIOUS INTENSITY FORECAST,

AND IS SIMILAR TO A BLEND OF THE FSSE AND HCCA MODELS.



THE INITIAL MOTION ESTIMATE IS NORTH-NORTHWESTWARD OR 330/10 KT.

JOHN IS EXPECTED TO RETURN TO A NORTHWESTWARD MOTION AT A SLIGHTLY

FASTER FORWARD SPEED LATER THIS MORNING, AND THEN CONTINUE THAT

MOTION FOR THE NEXT 72 HOURS. AFTER THAT TIME, A TURN TOWARD THE

WEST-NORTHWESTWARD IS FORECAST DUE TO THE WEAKENING AND SHALLOW

CYCLONE BEING STEERED BY THE LOW-LEVEL TRADE WIND FLOW. THE NEW