194 
 WTPA41 PHFO 250234
 TCDCP1
 
 TROPICAL DEPRESSION SIX-C DISCUSSION NUMBER   1
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP062015
 500 PM HST THU SEP 24 2015
  
 RECENT SATELLITE IMAGES SHOWED THAT A TROPICAL DISTURBANCE SOUTHEAST
 OF THE MAIN HAWAIIAN ISLANDS HAS DEVELOPED DEEP CONVECTION WITHIN A
 CURVED BAND NEAR ITS CENTER. IN ADDITION...A 1953 UTC ASCAT PASS
 SHOWED WINDS AT 30 KT WITHIN 80 NM OF THE DISTURBANCE/S EASTERN
 SEMICIRCLE. SUBJECTIVE DVORAK FIXES UNANIMOUSLY CAME IN AT 2.0/30
 KT. AS A RESULT OF THESE DATA...ADVISORIES ARE BEING INITIATED ON
 TROPICAL DEPRESSION SIX-C. THIS IS THE ELEVENTH TROPICAL CYCLONE IN
 THE CENTRAL NORTH PACIFIC BASIN FOR THE 2015 SEASON AND TIES THE
 RECORD FOR THE MOST ACTIVE SEASON WHICH WAS SET IN 1992 AND
 REPEATED IN 1994.
 
 THE DEPRESSION IS MOVING AT 320/7 KT TOWARDS A WEAKNESS IN THE
 SUBTROPICAL RIDGE. THIS MOTION IS EXPECTED TO CONTINUE OVER THE NEXT
 COUPLE OF DAYS. A LARGE MIDDLE AND UPPER LEVEL LOW PRESSURE SYSTEM
 CURRENTLY FAR NORTHEAST OF THE HAWAIIAN ISLANDS IS FORECAST TO MOVE
 TOWARD THE SOUTHEAST. AN ASSOCIATED TROUGH EXTENDING SOUTHWEST FROM
 THE LOW WILL SHIFT SOUTHWARD...RESULTING IN AN INCREASE IN UPPER
 LEVEL SOUTHWESTERLIES...AND VERTICAL WIND SHEAR...THAT WILL IMPACT
 THE TROPICAL CYCLONE. GLOBAL MODELS SHOW THAT THE VERTICAL SHEAR
 WILL DECOUPLE THE SYSTEM BEYOND 48 HOURS...WHICH MEANS THE
 CYCLONE WILL BECOME SHALLOW AND MOVE WITH THE LOWER LEVEL STEERING
 CURRENT. THE RELIABLE DYNAMICAL MODELS ARE IN GENERAL AGREEMENT WITH
 THIS SCENARIO AND ARE FAIRLY CLOSE TO EACH OTHER WITH THE MAIN
 DIFFERENCES BEING THE FORWARD SPEED AFTER DECOUPLING OCCURS. THE
 TRACK FORECAST FOR THIS ADVISORY CLOSELY FOLLOWS THE DYNAMIC
 CONSENSUS AND IS BETWEEN THE GFS TO THE SOUTH AND THE ECMWF TO THE
 NORTH.
 
 TROPICAL DEPRESSION SIX-C IS PASSING OVER WARM WATER...28C TO 29C
 BASED ON THE LATEST ANALYSIS. MODERATE SHEAR IS ALREADY AFFECTING
 THE SYSTEM ACCORDING TO THE 0000 UTC CIMSS ANALYSIS AND IS FORECAST
 TO INCREASE...ESPECIALLY BEYOND 48 HOURS. BEFORE THE STRONGER SHEAR
 SETS IN AND DECOUPLES THE CYCLONE...THERE APPEARS TO BE A WINDOW OF
 OPPORTUNITY FOR STRENGTHENING. THUS...THE FORECAST CALLS FOR SIX-C
 TO BECOME A TROPICAL STORM TONIGHT FOLLOWED BY STEADY WEAKENING
 AFTER 36 HOURS. IF IT DOES BECOME A TROPICAL STORM IT WILL BE NAMED
 NIALA...PRONOUNCED NEE-AH-LA. 
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  25/0300Z 14.5N 149.3W   30 KT  35 MPH
  12H  25/1200Z 15.1N 150.0W   35 KT  40 MPH
  24H  26/0000Z 16.2N 151.0W   40 KT  45 MPH
  36H  26/1200Z 17.0N 152.2W   40 KT  45 MPH
  48H  27/0000Z 17.4N 153.5W   35 KT  40 MPH
  72H  28/0000Z 17.5N 156.0W   30 KT  35 MPH
  96H  29/0000Z 17.0N 157.5W   30 KT  35 MPH
 120H  30/0000Z 16.5N 159.0W   25 KT  30 MPH
  
 $$
 FORECASTER KODAMA