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WTPA42 PHFO 080855
TCDCP2
HURRICANE OHO DISCUSSION NUMBER 21
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP072015
1100 PM HST WED OCT 07 2015
OHO IS BEGINNING EXTRATROPICAL TRANSITION...WITH AN INCREASINGLY
SHEARED SATELLITE PRESENTATION. SHIPS AND UW-CIMSS ANALYSES SHOW 45
TO 50 KT OF SOUTH SOUTHWESTERLY SHEAR...WHILE SHIPS ALSO SHOWS OHO
MOVING ACROSS 23C WATER. THE LOW LEVEL CIRCULATION
CENTER...LLCC...REMAINS EXPOSED...WITH ALL REMAINING DEEP
CONVECTION PUSHED OFF TO THE NORTH NORTHEAST. SUBJECTIVE DVORAK
SATELLITE INTENSITY ESTIMATES WERE 4.0...65 KT...FROM PHFO AND
JTWC...WHILE UW-CIMSS ADT HAS OHO AT 55 KT. OHO IS SPINNING DOWN AS
A TROPICAL SYSTEM...SO SETTING THE INITIAL INTENSITY AT 65 KT FOR
THIS ADVISORY SEEMS REASONABLE.
INITIAL MOTION IS 030/34 KT. OHO HAS BEEN SCOOPED UP BY DEEP
TROUGHING TO ITS NORTHWEST AND IS NOW RACING NORTH NORTHEASTWARD
TOWARD THE MAINLAND. SINCE OHO WILL LIKELY COMPLETE EXTRATROPICAL
TRANSITION WITHIN 12 HOURS...WE COLLABORATED WITH THE OCEAN
PREDICTION CENTER...OPC...FOR ALL POINTS ALONG THE FORECAST TRACK.
OPC KINDLY CONTRIBUTED WIND AND SEAS RADII AS WELL. THE CURRENT
FORECAST TRACK KEEPS OHO HEADED TOWARD BRITISH COLUMBIA THROUGH 24
HOURS...THEN CURVES THE TRACK NORTHWESTWARD AT 36 AND 48 HOURS AS
THIS SYSTEM MOVES ALONG THE NORTHEASTERN FLANK OF A LARGE POLAR LOW
FORMING ACROSS THE ALEUTIANS. AS OHO BECOMES AN EXTRATROPICAL
STORM LOW...ITS WIND FIELD WILL EXPAND AND BECOME HIGHLY ASYMMETRIC.
OHO WILL WEAKEN THROUGH 24 HOURS...SPINNING DOWN AT THE MET RATE
ACCORDING TO CONCEPTUAL MODELS. HOWEVER...BAROCLINIC FORCES WILL
STRENGTHEN THE REMNANTS OF OHO BACK TO HURRICANE STRENGTH AS AN
EXTRATROPICAL STORM LOW BETWEEN 24 AND 36 HOURS. THIS STORM LOW
WILL THEN WEAKEN AGAIN BY 48 HOURS AS IT INTERACTS WITH THE ALASKAN
PANHANDLE...THEN DISSIPATE INLAND BY 72 HOURS.
THE CENTRAL PACIFIC HURRICANE CENTER WILL ISSUE ONE MORE ADVISORY
AFTER THIS ONE TO CLOSE THINGS DOWN WITH OHO PROPERLY. OHO WILL
BECOME EXTRATROPICAL BEFORE CROSSING 140W...SO AFTER THE 1500 UTC
ADVISORY CYCLE IT WILL BECOME THE RESPONSIBILITY OF OPC AND WILL BE
COVERED BY OPC HIGH SEAS FORECASTS.
FORECAST POSITIONS AND MAX WINDS
INIT 08/0900Z 32.5N 143.1W 65 KT 75 MPH...BECOMING EXTRATROPICAL
12H 08/1800Z 37.0N 140.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
24H 09/0600Z 47.0N 136.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 09/1800Z 55.0N 137.0W 75 KT 85 MPH...POST-TROP/EXTRATROP
48H 10/0600Z 59.0N 140.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
72H 11/0600Z...DISSIPATED
$$
FORECASTER POWELL
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