439 
 WTPA42 PHFO 232100
 TCDCP2
 
 TROPICAL STORM NEKI DISCUSSION NUMBER  21
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP032009
 1100 AM HST FRI OCT 23 2009
 
 SATELLITE IMAGERY SHOWS THAT NEKI CONTINUES TO DETERIORATE THIS 
 MORNING. VISIBLE IMAGES ARE NOW REVEALING A PARTIALLY EXPOSED LLCC.
 THE LAYERED CLOUDS AND WHAT REMAINS OF THE DEEP CONVECTION HAVE
 BEEN PUSHED TO THE NORTHEAST OF THE CENTER BY 25 TO 30 KT OF
 SOUTHWESTERLY SHEAR...AS ANALYZED IN THE UW/CIMSS SHEAR ANALYSIS.
 CURRENT INTENSITY ESTIMATES FROM PHFO...JTWC...AND SAB WERE A
 CONSENSUS 3.5 AND SO THE INTENSITY ESTIMATE WAS SET TO 55 KT FOR
 THIS ADVISORY. 
 
 THE INITIAL MOTION ESTIMATE IS 025/4. NEKI IS LOCATED IN A COL
 BETWEEN SUBTROPICAL HIGH PRESSURE CENTERS TO THE EAST AND WEST...
 THE LOWER EQUATORIAL PRESSURE TO THE SOUTH...AND A SERIES OF 
 EXTRATROPICAL LOW PRESSURE CENTERS PASSING BY TO THE NORTH. THE 
 MID-LATITUDE SHORTWAVE TROUGHS PASSING BY TO THE NORTH OF NEKI WILL 
 LEAVE THE CYCLONE BEHIND...WITH HIGH PRESSURE BUILDING TO THE NORTH 
 THROUGH 36 TO 48 HOURS. THIS WILL KEEP NEKI IN RELATIVELY WEAK 
 STEERING CURRENTS. BEYOND 48 HOURS...A MUCH STRONGER MID-LATITUDE 
 TROUGH IS EXPECTED TO SWEEP NEKI INTO THE  WESTERLIES. THERE IS SOME 
 DISAGREEMENT ABOUT THE EVOLUTION OF WHAT IS LEFT OF NEKI AFTER 
 THAT...WHETHER THE CYCLONE BEGINS TO MERGE WITH EXTRATROPICAL LOW 
 PRESSURE...OR WHETHER THE LOW LEVEL CENTER BECOMES BECOMES ELONGATED 
 AND TORN APART. THE OFFICIAL FORECAST IS CLOSE TO...BUT SOMEWHAT 
 SLOWER THAN THE PREVIOUS FORECAST IN THE SHORT TERM...WITH A SLIGHT 
 ADJUSTMENT TO THE LEFT IN THE LONGER TERM.
 
 STRONG SOUTHWEST SHEAR IS EXPECTED TO CONTINUE OVER THE CYCLONE
 THROUGH AT LEAST THE NEXT 48 HOURS. SOME OF THE GLOBAL MODELS
 SUGGEST THAT SHEAR WILL WEAKEN BEYOND 48 HOURS...BUT BY THEN NEKI
 WILL BE APPROACHING THE MUCH COLDER WATERS OF THE NORTH PACIFIC.
 AGAIN...IT IS UNCERTAIN HOW MUCH BAROCLINIC ENHANCEMENT NEKI COULD
 GET IN THE LONGER RANGE. LITTLE CHANGE TO THE INTENSITY FORECAST
 WAS MADE THROUGH 36 HOURS...WITH A SLIGHTLY SLOWER WEAKENING TREND
 INDICATED FOR 48 HOURS AND BEYOND.
 
 THE CLOSEST AVAILABLE OBSERVATION...FROM BUOY 51001...INDICATED
 WINDS GUSTING TO 35 KT AT 1750 UTC. BASED ON THIS...AND MORE
 IMPORTANTLY ON THE VERY TIMELY QUIKSCAT WIND PASS FROM 1705 UTC...
 WE HAVE MADE SOME ADJUSTMENTS TO THE WIND RADII. NEKI/S RELATIVELY
 CLOSE APPROACH TO THE MAIN HAWAIIAN ISLANDS IS A SOBERING REMINDER
 THAT WE STILL HAVE MORE THAN A MONTH TO GO IN HURRICANE SEASON.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      23/2100Z 23.1N 165.3W    55 KT
  12HR VT     24/0600Z 23.7N 165.1W    50 KT
  24HR VT     24/1800Z 24.8N 164.6W    45 KT
  36HR VT     25/0600Z 25.8N 164.0W    40 KT
  48HR VT     25/1800Z 27.1N 163.2W    35 KT
  72HR VT     26/1800Z 30.6N 161.1W    30 KT...DISSIPATING
  96HR VT     27/1800Z 36.9N 157.4W    25 KT...EXTRATROPICAL
  
 $$
 FORECASTER R BALLARD