WTPA42 PHFO 240901 TCDCP2 TROPICAL STORM NEKI DISCUSSION NUMBER 23 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009 1100 PM HST FRI OCT 23 2009 THE LATEST UW/CIMSS ESTIMATE OF VERTICAL WIND SHEAR AFFECTING TROPICAL STORM NEKI IS 23 KT FROM 256 DEGREES. THIS HOSTILE ENVIRONMENT IS BEING CREATED IN PART DUE TO AN UPPER TROPOSPHERIC TROUGH...WHICH IS EVIDENT IMMEDIATELY TO THE WEST AND NORTHWEST OF NEKI ACCORDING TO LOOPS OF WATER VAPOR IMAGERY AND SATELLITE DERIVED UPPER LEVEL WINDS. THERE IS ALSO A LARGE UPPER LEVEL ANTICYCLONE LOCATED SOUTH OF THE ALOHA STATE NEAR 17N 160W. THE TROPICAL STORM IS CERTAINLY FEELING THESE ADVERSE CONDITIONS BASED ON ITS APPEARANCE IN SATELLITE IMAGERY THIS EVENING. A HUGE SWATH OF CIRRUS CLOUDS IS STREAMING MORE THAN 500 NM TOWARD THE NORTHEAST AWAY FROM THE REMAINING CENTRAL DENSE OVERCAST...OR CDO...LOCATED NEAR THE CENTER. THE SOUTHWESTERN EDGE OF THE CDO ALSO HAS A DISTINCT BOUNDARY INDICATING THE INHIBITION OF THE OUTFLOW IN THAT PORTION OF THE STORM DUE TO THE RELATIVELY STRONG UPPER LEVEL SOUTHWESTERLY WINDS. THE POOR APPEARANCE OF TROPICAL STORM NEKI IN SATELLITE IMAGERY ALSO CAUSES PROBLEMS FOR THOSE OF US WHO ARE TRYING TO DETERMINE THE LOCATION OF ITS LOW LEVEL CENTER. THERE IS SOME SPREAD IN THE POSITIONS FROM SAB...JTWC AND PHFO. HOWEVER...NEKI HAS BEEN MOVING RATHER SLOWLY...SO IT APPEARS TO BE CLOSE TO THE LATEST OFFICIAL POSITION...WHICH YIELDS A MOVEMENT OF 025 DEG/04 KT. ALSO...BASED ON CURRENT INTENSITY ESTIMATES OF T3.0-3.5...THE INTENSITY IS MAINTAINED AT 55 KT FOR THIS ADVISORY. THE CURRENT TRACK FORECAST IS AN UPDATE OF THE PREVIOUS ONE WITH SOME MINOR TWEAKS THROUGH 48 HOURS. WEAK STEERING CONDITIONS WILL LIKELY CONTINUE THROUGH THAT TIME PERIOD. NEKI WILL LIKELY ACCELERATE BEYOND 48 HOURS ONCE IT IS PICKED UP BY A NEW LARGE AMPLITUDE UPPER LEVEL TROUGH THAT IS FORECAST TO DIG TOWARD THE EAST SOUTHEAST. THE INTENSITY FORECAST IS ALSO UNCHANGED THROUGH DAY 2. HAVE KEPT GALE FORCE WINDS IN THE 72/96 HOUR PERIOD WHEN NEKI IS EXPECTED TO BE TRANSITIONING INTO AN EXTRATROPICAL SYSTEM. HAVE ALSO ADJUSTED THE WIND RADII...PARTICULARLY IN THE SOUTHEAST QUADRANT... TO ACCOUNT FOR THE MORE NORTHEASTWARD MOTION OF THE STORM. THE 0530 UTC QUIKSCAT PASS THAT CAME IN A FEW MINUTES AGO APPEARS TO SUPPORT THE INITIAL WIND RADII. WILL HAVE TO DETERMINE LATER TONIGHT IF ADVERSE WEATHER AND SEA CONDITIONS ARE BEGINNING TO SUBSIDE IN THE TROPICAL STORM WARNING AREA. FOR THE MOMENT...THERE IS NO CHANGE IN THE WARNINGS. FORECAST POSITIONS AND MAX WINDS INITIAL 24/0900Z 23.8N 164.9W 55 KT 12HR VT 24/1800Z 24.6N 164.5W 50 KT 24HR VT 25/0600Z 25.6N 164.0W 45 KT 36HR VT 25/1800Z 26.7N 163.4W 40 KT 48HR VT 26/0600Z 28.3N 163.0W 35 KT 72HR VT 27/0600Z 35.0N 160.0W 35 KT...BECOMING EXTRATROPICAL 96HR VT 28/0600Z 47.0N 152.0W 35 KT...EXTRATROPICAL $$ FORECASTER HOUSTON