769  
WTPA45 PHFO 140242  
TCDCP5  
 
POST-TROPICAL CYCLONE OLIVIA DISCUSSION NUMBER 54  
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP172018  
500 PM HST THU SEP 13 2018  
 
AN EARLIER FLARE UP OF DEEP CONVECTION WITHIN THE NORTHEAST AND EAST  
FLANKS OF OLIVIA CAUSED THE LOW-LEVEL CENTER TO SLOW DOWN, THEN  
ACCELERATE OFF TO THE WEST AS NEARBY THUNDERSTORMS COLLAPSED. STRONG  
WESTERLY VERTICAL WIND SHEAR OF AROUND 35 KT HAS NOW DISPLACED THE  
DIMINISHING CONVECTION NEARLY 90 N MI TO THE EAST OF THE ELONGATED  
AND FULLY EXPOSED LOW-LEVEL CENTER. HFO CAME UP WITH A SUBJECTIVE  
DVORAK CURRENT INTENSITY ESTIMATE OF 1.5, WHILE JTWC AND SAB ARE NO  
LONGER CLASSIFYING THE SYSTEM. GIVEN THE LACK OF ORGANIZED DEEP  
CONVECTION, OLIVIA IS DEEMED A POST-TROPICAL LOW WITH AN INTENSITY  
OF 30 KT, AND THIS WILL BE THE LAST ADVISORY.  
 
THE INITIAL MOTION IS SET AT WEST (260 DEGREES) AT 13 KT. THE WEAK  
LOW-LEVEL CENTER WAS EARLIER DRAWN TOWARD A PULSING AREA OF  
CONVECTION, THEN RECENTLY EMERGED FARTHER NORTH THAN EXPECTED,  
LEADING TO SOME UNCERTAINTY IN THE INITIAL MOTION. A LOW-LEVEL RIDGE  
TO THE NORTH WILL STEER THE REMNANT LOW OF OLIVIA WESTWARD THROUGH  
TOMORROW. INCREASED INTERACTION WITH A DEVELOPING UPPER-LEVEL LOW  
SITTING JUST NORTH OF THE REMNANT SURFACE LOW WILL CAUSE A TURN  
TOWARD THE WEST-NORTHWEST FRIDAY NIGHT AND SATURDAY. THE UPPER-LEVEL  
LOW WILL MAINTAIN STRONG VERTICAL WIND SHEAR THAT SHOULD LEAD TO  
DISSIPATION OF THE REMNANT SURFACE LOW DURING THE WEEKEND. THE  
INTENSITY FORECAST IS IN LINE WITH THE SHIPS AND LGEM GUIDANCE.  
 
 
FORECAST POSITIONS AND MAX WINDS  
 
INIT 14/0300Z 18.9N 164.2W 30 KT 35 MPH...POST-TROPICAL  
12H 14/1200Z 18.8N 166.1W 30 KT 35 MPH...POST-TROP/REMNT LOW  
24H 15/0000Z 19.1N 168.6W 25 KT 30 MPH...POST-TROP/REMNT LOW  
36H 15/1200Z 19.8N 171.0W 25 KT 30 MPH...POST-TROP/REMNT LOW  
48H 16/0000Z 20.8N 173.3W 25 KT 30 MPH...POST-TROP/REMNT LOW  
72H 17/0000Z...DISSIPATED  
 

 
FORECASTER WROE  
 
 
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