574  
WTNT43 KNHC 121459  
TCDAT3  
 
POST-TROPICAL CYCLONE CHRIS DISCUSSION NUMBER 24  
NWS NATIONAL HURRICANE CENTER MIAMI FL AL032018  
1100 AM AST THU JUL 12 2018  
 
EXTRATROPICAL TRANSITION HAS BEEN ONGOING FOR THE PAST FEW HOURS,  
WITH THE RAIN SHIELD CONTINUING TO EXPAND AND CLOUDS TOPS WARMING IN  
THE NORTHWESTERN SEMICIRCLE. IN ADDITION, SURFACE OBSERVATIONS CLOSE  
TO THE CENTER NOW SHOW A SHARP TEMPERATURE GRADIENT OF ALMOST 20 DEG  
F ACROSS THE CENTER, WHICH IS INDICATIVE OF THE CYCLONE HAVING  
MERGED WITH A COLD FRONTAL SYSTEM. AS A RESULT, CHRIS HAS BECOME A  
POST-TROPICAL/EXTRATROPICAL CYCLONE. THE INTENSITY OF 60 KT IS BASED  
ON CONTINUITY WITH THE PREVIOUS ADVISORY AND EARLIER ASCAT  
SCATTEROMETER PASSES. GRADUAL WEAKENING IS FORECAST BY ALL OF THE  
INTENSITY MODEL GUIDANCE, BUT THE CYCLONE IS STILL EXPECTED TO  
REMAIN A GALE AREA THROUGH 72 HOURS.  
 
CHRIS HAS MADE A SLIGHT WESTWARD JOG, BUT THE LATEST MODEL GUIDANCE  
INSISTS THAT THE CYCLONE WILL START MOVING BACK TOWARD THE NORTHEAST  
OR 045 DEGREES AT 30-31 KT. POST-TROPICAL CYCLONE CHRIS IS FORECAST  
TO REMAIN EMBEDDED WITHIN THE FAST MID-LATITUDE WESTERLY FLOW ON THE  
EAST SIDE OF A BROAD, DEEP-LAYER TROUGH MOVING EASTWARD OVER THE  
NORTHEASTERN UNITED STATES AND SOUTHEASTERN CANADA FOR THE NEXT 48  
HOURS OR SO. BY 72 HOURS, THE CYCLONE IS EXPECTED TO SLOW DOWN AND  
BEGIN MOVING NORTHWARD AS IT INTERACTS WITH A LARGER MID-LATITUDE  
UPPER-LEVEL LOW. THE NHC MODEL GUIDANCE REMAINS TIGHTLY PACKED, SO  
ONLY MINOR ADJUSTMENTS TO THE PREVIOUS ADVISORY TRACK WERE REQUIRED,  
AND MAINLY IN JUST THE FIRST 12 HOURS. ON THE FORECAST TRACK, THE  
CENTER OF CHRIS IS EXPECTED TO PASS OVER OR NEAR THE AVALON  
PENINSULA OF SOUTHEASTERN NEWFOUNDLAND AROUND 2100-0000 UTC THIS  
AFTERNOON AND EVENING.  
 
THIS IS THE LAST PUBLIC ADVISORY ISSUED BY THE NATIONAL HURRICANE  
CENTER ON THIS SYSTEM. ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE  
FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE,  
UNDER AWIPS HEADER NFDHSFAT1, WMO HEADER FZNT01 KWBC, AND AVAILABLE  
ON THE WEB AT HTTPS://OCEAN.WEATHER.GOV/SHTML/NFDHSFAT1.SHTML. OTHER  
INFORMATION ON POST-TROPICAL CYCLONE CHRIS CAN BE FOUND IN PRODUCTS  
ISSUED BY ENVIRONMENT CANADA/CANADIAN HURRICANE CENTRE ON THE  
INTERNET AT WEATHER.GC.CA/HURRICANE/.  
 
 
FORECAST POSITIONS AND MAX WINDS  
 
INIT 12/1500Z 44.4N 57.7W 60 KT 70 MPH...POST-TROPICAL  
12H 13/0000Z 47.7N 52.8W 55 KT 65 MPH...POST-TROP/EXTRATROP  
24H 13/1200Z 50.7N 44.7W 45 KT 50 MPH...POST-TROP/EXTRATROP  
36H 14/0000Z 53.5N 35.0W 40 KT 45 MPH...POST-TROP/EXTRATROP  
48H 14/1200Z 56.5N 26.5W 35 KT 40 MPH...POST-TROP/EXTRATROP  
72H 15/1200Z 61.6N 18.9W 35 KT 40 MPH...POST-TROP/EXTRATROP  
96H 16/1200Z...DISSIPATED  
 

 
FORECASTER STEWART  
 
 
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