341
WTPA45 PHFO 242039
TCDCP5
TROPICAL STORM ANA DISCUSSION NUMBER 45
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP022014
1100 AM HST FRI OCT 24 2014
ANA CONTINUES TO PRODUCE PULSING CENTRAL DEEP CONVECTION. RECENT
IMAGES HAVE ALSO SHOWN TRANSIENT WARM SPOTS APPEARING IN THE
INFRARED IMAGERY. AN SSMIS PASS FROM 1912 UTC INDICATED AN
EYEWALL-LIKE STRUCTURE TO THE EAST OF THE CENTER. EARLIER MICROWAVE
PASSES FROM 1812 AND 1557 UTC SHOWED THIS FEATURE TO BE A LITTLE
BETTER DEFINED. DVORAK INTENSITY ESTIMATES FROM THE FIX AGENCIES
CAME IN AT 45 KT/35 KT/30 KT FROM PHFO/SAB/JTWC. CIMSS SATCON WAS 49
KT WITH THE AMSU COMPONENT INDICATING 58 KT. GIVEN THE MICROWAVE
STRUCTURE FROM THE MOST RECENT PASSES AND THE OCCASIONAL WARM
SPOTS...THE INITIAL INTENSITY WILL LEAN TOWARD THE SATCON AND AMSU
ESTIMATES AND HAS BEEN INCREASED TO 55 KT FOR THIS FORECAST CYCLE.
THE INTIAL MOTION IS 020/11 KT AS ANA MOVES BETWEEN A
MID-LEVEL RIDGE TO ITS SOUTHEAST AND AN APPROACHING LOW PRESSURE
SYSTEM TO THE NORTHWEST. THIS IS A FASTER MOVEMENT FROM THE
PREVIOUS ADVISORY PACKAGE AND SIGNALS THE START OF AN EXPECTED
ACCELERATION TOWARD THE NORTHEAST. OBJECTIVE AIDS ARE RATHER
TIGHTLY PACKED...EVEN BEYOND DAY 3 WHEN ANA TRANSITIONS TO AN
EXTRATROPICAL SYSTEM. THUS...THE FORECAST TRACK CLOSELY FOLLOWS THE
PREVIOUS PACKAGE THROUGH 36 HOURS EXCEPT FOR A SLIGHT NORTHWARD
NUDGE TO ALIGN IT CLOSER TO THE DYNAMIC CONSENSUS. BEYOND 36
HOURS...THE FORECAST TRACK IS BASED ON THE GLOBAL MODELS AND
GUIDANCE FROM THE NOAA OCEAN PREDICTION CENTER AS ANA HEADS TOWARD
THE NORTH AMERICAN CONTINENT.
IN THE SHORT TERM...ANA WILL BE UNDER MODEST VERTICAL WIND SHEAR
AND IS TRANSITING MARGINAL SEA SURFACE TEMPERATURE
CONDITIONS. THIS IS EXPECTED TO ALLOW A MAINTENANCE OF STRONG
TROPICAL STORM INTENSITIES...WHICH IS CONSISTENT WITH THE SHIPS
GUIDANCE THROUGH 36 HOURS. BEYOND 36 HOURS...ANA SHOULD BEGIN AN
EXTRATROPICAL TRANSITION ALONG A TRACK THAT WILL TAKE IT OVER
PROGRESSIVELY COOLER TEMPERATURES AND INCREASING VERTICAL SHEAR.
THUS...THE INTENSITY FORECAST BEYOND 36 HOURS IS LARGELY BASED ON
NOAA OCEAN PREDICTION CENTER GUIDANCE WHICH CALLS FOR SLOW
WEAKENING AS AN EXTRATROPICAL CYCLONE UNTIL DISSIPATION AT 120
HOURS.
FORECAST POSITIONS AND MAX WINDS
INIT 24/2100Z 29.7N 169.3W 55 KT 65 MPH
12H 25/0600Z 31.5N 167.3W 55 KT 65 MPH
24H 25/1800Z 34.5N 163.2W 55 KT 65 MPH
36H 26/0600Z 38.4N 157.2W 50 KT 60 MPH
48H 26/1800Z 42.9N 148.7W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 27/1800Z 47.9N 138.7W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 28/1800Z 50.0N 130.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
120H 29/1800Z...DISSIPATED
$$
FORECASTER KODAMA
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