WTPA42 PHFO 192106 TCDCP2 TROPICAL STORM NEKI DISCUSSION NUMBER 5 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009 1100 AM HST MON OCT 19 2009 TROPICAL STORM NEKI CONTINUES TO ORGANIZE ITSELF FAR SOUTH OF THE MAIN HAWAIIAN ISLANDS. THE LATEST FIXES FROM PHFO...SAB AND JTWC ALL INDICATED A CURRENT INTENSITY OF 35 KT SO THE INITIAL INTENSITY WILL BE HELD AT 35 KT FOR THIS FORECAST PACKAGE. IT APPEARS THAT THE SYSTEM/S CENTER IS ON THE SOUTHEAST SIDE OF A LARGE CONVECTIVE CURVED BAND BASED ON THE INITIAL VISIBLE IMAGES OF THE DAY AND RECENT MICROWAVE DATA. THIS RESULTED IN A RELOCATION OF THE CENTER NORTHEAST OF THE PREVIOUS FORECAST POSITION. NEKI IS MOVING TOWARD THE NORTHWEST AT 13 KT TO THE SOUTH OF A WEAKNESS IN THE SUBTROPICAL RIDGE. THIS GENERAL MOTION SHOULD CONTINUE OVER THE NEXT 36 HOURS. A SLOWING IN FORWARD SPEED IS FORECAST BEYOND 36 HOURS AS A MIDLATITUDE TROUGH PASSES TO THE NORTH AND PRODUCES A SIGNIFICANT WEAKNESS IN THE STEERING CURRENT. THE OBJECTIVE AIDS ARE IN GENERAL AGREEMENT WITH THIS SCENARIO WITH THE ECMWF...GFS...HWRF AND GFDL ON THE NORTH SIDE OF THE ENVELOPE AND UKMET AND NOGAPS TO THE SOUTH. THE FORECAST TRACK HAS BEEN NUDGED A BIT NORTH OF THE PREVIOUS PACKAGE DUE TO THE ADJUSTMENT OF THE INITIAL POSITION. THE FORECAST ALSO IS WITHIN THE HWRF/GFS/GFDL CLUSTER IN DEFERENCE TO THE SATISFACTORY PERFORMANCE OF THESE 3 MODELS WITH NEKI SO FAR. THIS KEEPS NEKI WELL SOUTHWEST OF THE MAIN HAWAIIAN ISLANDS. THE TRACK ALSO TAKES THE CENTER OF NEKI SOMEWHAT NORTHEAST OF JOHNSTON ISLAND BUT UNCERTAINTIES IN THE FORECAST TRACK AND THE PRESENCE OF HURRICANE-RELATED EFFECTS AWAY FROM THE CENTER STILL KEEPS THIS SMALL PACIFIC ISLAND AT RISK. INTERESTS ON OR NEAR JOHNSON ISLAND SHOULD CLOSELY MONITOR THE PROGRESS OF THIS TROPICAL CYCLONE. CONDITIONS REMAIN VERY MUCH FAVORABLE FOR INTENSIFICATION. RECENT SATELLITE IMAGES SHOW A SLIGHT DECREASE IN DEEP CONVECTIVE ACTIVITY BUT THIS IS LIKELY DUE TO NORMAL DIURNAL TENDENCY RATHER THAN POOR ENVIRONMENTAL CONDITIONS. CONVECTION SHOULD BECOME REINVIGORATED DURING THE NIGHTTIME HOURS. SEA SURFACE TEMPERATURES RANGE FROM 28C TO NEARLY 29C ALONG THE FORECAST TRACK. OCEANIC HEAT CONTENT IS NOT AN INHIBITING FACTOR BASED ON THE LATEST CIRA ANALYSIS. THE CIMSS ANALYSIS SHOWS VERTICAL WIND SHEAR AT ONLY 1.1 M/S AND THUS INDICATES FAVORABLE CONDITIONS FOR INTENSIFICATION. SHEAR IS EXPECTED TO REMAIN WEAK OVER THE NEXT SEVERAL DAYS. THE OBJECTIVE GUIDANCE SHOWS CONTINUED INTENSIFICATION WITH A PEAK AT AROUND 96 HOURS. THE FORECAST THUS CALLS FOR NEKI TO BECOME A HURRICANE AT 36 HOURS WITH A PEAK INTENSITY OF 90 KT WHICH IS CLOSE TO THE CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 19/2100Z 10.7N 159.6W 35 KT 12HR VT 20/0600Z 12.0N 161.2W 40 KT 24HR VT 20/1800Z 13.7N 163.6W 50 KT 36HR VT 21/0600Z 15.2N 165.5W 65 KT 48HR VT 21/1800Z 16.3N 166.3W 75 KT 72HR VT 22/1800Z 17.8N 167.9W 85 KT 96HR VT 23/1800Z 19.2N 169.5W 90 KT 120HR VT 24/1800Z 20.6N 172.3W 85 KT $$ FORECASTER KODAMA