WTPA42 PHFO 200903 TCDCP2 TROPICAL STORM NEKI DISCUSSION NUMBER 7 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009 1100 PM HST MON OCT 19 2009 NEKI IS LOOKING MORE LIKE A TYPICAL TROPICAL CYCLONE THIS EVENING. THE CONVECTIVE BANDS ON THE PERIPHERY OF THE SYSTEM HAVE BECOME LESS APPARENT WHILE ACTIVE CONVECTION HAS INCREASED NEAR THE CENTER. THE 0600 UTC FIXES FROM PHFO...SAB AND JTWC RANGED FROM 2.5 TO 3.0. WE HAVE MADE THE INITIAL INTENSITY 40 KT...IN THE MIDDLE OF THE FIX RANGE. TROPICAL STORM NEKI CONTINUES TO MOVE NORTHWESTWARD TO THE SOUTH OF A WEAKNESS IN THE SUBTROPICAL RIDGE. THE OBJECTIVE AIDS REMAIN FAIRLY TIGHTLY GROUPED...SHOWING A TRACK THAT CURVES LIKE A BACKWARD LETTER S. THE MODELS DIFFER MAINLY IN HOW SHARPLY THE TRACK CURVES. THE CURRENT FORECAST REMAINS CLOSE TO THE PREVIOUS TRACK. NEKI IS FORECAST TO CONTINUE NORTHWESTWARD WITH A GRADUAL TURN TO THE NORTH NORTHWEST AFTER 36 HOURS AND A SLOWING OF THE FORWARD SPEED. THIS IS DUE TO A TROUGH PASSING BY FROM WEST TO EAST NORTH OF THE SYSTEM. AFTER THE TROUGH PASSES...AND RIDGING ALOFT REBUILDS NORTHWEST OF THE CYCLONE...THE TRACK TURNS BACK TOWARD THE WEST NORTHWEST. THE LATEST FORECAST KEEPS NEKI WELL SOUTHWEST OF THE MAIN HAWAIIAN ISLANDS. HOWEVER...THE TRACK ALSO TAKES THE CENTER OF NEKI CLOSE ENOUGH TO JOHNSTON ISLAND TO WARRANT THE ISSUANCE OF A HURRICANE WATCH SINCE THE LEAD TIME REQUIREMENT IS 48 HOURS IN THE CENTRAL PACIFIC BASIN. THE FORECAST TRACK WILL KEEP NEKI OVER 28 DEGREE CELSIUS WATER FOR THE NEXT 120 HOURS. SHIPS GUIDANCE SHOWS 10 KT NORTHEAST SHEAR INCREASING A BIT TO 15 KT IN 18 HOURS...THEN DROPPING TO LESS THEN 10 KT. THESE ENVIRONMENTAL FACTORS SHOULD BE FAVORABLE ENOUGH TO ALLOW NEKI TO CONTINUE INTENSIFYING. WE HAVE SLOWED THE INTENSIFICATION A BIT FROM THE PREVIOUS FORECAST BUT STILL HAVE NEKI REACHING HURRICANE STRENGTH IN 36 HOURS. FORECAST POSITIONS AND MAX WINDS INITIAL 20/0900Z 12.4N 162.3W 40 KT 12HR VT 20/1800Z 13.8N 163.9W 45 KT 24HR VT 21/0600Z 15.7N 166.0W 55 KT 36HR VT 21/1800Z 17.3N 167.2W 65 KT 48HR VT 22/0600Z 18.5N 167.8W 75 KT 72HR VT 23/0600Z 20.1N 169.0W 80 KT 96HR VT 24/0600Z 21.5N 170.5W 80 KT 120HR VT 25/0600Z 22.0N 173.0W 75 KT $$ FORECASTER DONALDSON