141  
WTNT42 KNHC 100831  
TCDAT2  
 
TROPICAL STORM OPHELIA DISCUSSION NUMBER 5  
NWS NATIONAL HURRICANE CENTER MIAMI FL AL172017  
500 AM AST TUE OCT 10 2017  
 
ALTHOUGH THE INTENSITY OF OPHELIA'S DEEP CONVECTION HAS DECREASED  
DURING THE PAST SEVERAL HOURS, THE CLOUD PATTERN HAS IMPROVED  
AND BECOME MORE SYMMETRIC WITH BANDING FEATURES NOW BETTER  
ESTABLISHED AROUND THE CENTER. THE INITIAL INTENSITY IS HELD AT 45  
KT, IN AGREEMENT WITH A DVORAK CLASSIFICATION FROM SAB AND THE  
LATEST SATELLITE CONSENSUS ESTIMATE FROM CIMSS AT THE UNIVERSITY OF  
WISCONSIN.  
 
THE RECENT DECREASE IN CONVECTION COULD BE ASSOCIATED WITH SOME DRY  
AIR THAT HAS WRAPPED INTO THE CIRCULATION, AS SEEN IN TOTAL  
PRECIPITABLE WATER IMAGERY. THE OTHER ENVIRONMENTAL CONDITIONS  
APPEAR GENERALLY CONDUCIVE FOR STRENGTHENING WITH WIND SHEAR VALUES  
EXPECTED TO DECREASE TO NEAR 10 KT DURING THE NEXT COUPLE OF DAYS  
WITH SSTS REMAINING MARGINALLY WARM AROUND 26.5 TO 27 DEG C.  
THESE CONDITIONS COMBINED WITH AN UNSTABLE ATMOSPHERE SHOULD ALLOW  
OPHELIA TO STRENGTHEN, AND THE NHC FORECAST FOLLOWS THE IVCN AND  
HCCA CONSENSUS MODELS AND BRINGS THE CYCLONE TO HURRICANE STRENGTH  
IN 24 TO 36 HOURS. ALTHOUGH THE OFFICIAL FORECAST SHOWS SLIGHT  
WEAKENING BY THE END OF THE PERIOD DUE TO AN INCREASE IN SHEAR AND  
COOLER WATERS, THE LATEST GUIDANCE SUGGESTS THAT THE WEAKENING  
COULD BE LESS THAN CURRENTLY FORECAST.  
 
SATELLITE FIXES INDICATE THAT OPHELIA HAS MADE A TURN TO THE  
SOUTHEAST, AS EXPECTED. A CONTINUED SLOW SOUTHEAST MOTION IS  
FORECAST DURING THE NEXT 36 TO 48 HOURS AS MID-LEVEL RIDGING  
BUILDS TO THE NORTH AND WEST OF THE STORM. AFTER THAT TIME, A TURN  
TO THE NORTHEAST OR EAST-NORTHEAST AT A PROGRESSIVELY FASTER PACE IS  
EXPECTED AS A MID- TO UPPER-LEVEL TROUGH APPROACHES OPHELIA. THE  
MODELS ARE IN FAIRLY GOOD AGREEMENT, AND ONLY MINOR CHANGES WERE  
MADE TO THE PREVIOUS NHC TRACK FORECAST. THIS PREDICTION LIES NEAR  
THE MIDDLE OF THE GUIDANCE ENVELOPE.  
 
FORECAST POSITIONS AND MAX WINDS  
 
INIT 10/0900Z 31.9N 38.8W 45 KT 50 MPH  
12H 10/1800Z 31.7N 38.4W 55 KT 65 MPH  
24H 11/0600Z 30.8N 37.9W 60 KT 70 MPH  
36H 11/1800Z 30.2N 37.4W 70 KT 80 MPH  
48H 12/0600Z 30.0N 36.8W 75 KT 85 MPH  
72H 13/0600Z 31.0N 35.0W 75 KT 85 MPH  
96H 14/0600Z 33.0N 30.5W 75 KT 85 MPH  
120H 15/0600Z 35.5N 23.5W 65 KT 75 MPH  
 

 
FORECASTER CANGIALOSI  
 
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