291 
 WTPA44 PHFO 060910
 TCDCP4
 
 TROPICAL STORM GUILLERMO DISCUSSION NUMBER  30
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP092015
 1100 PM HST WED AUG 05 2015
  
 STRONG VERTICAL WIND SHEAR AND THE ENTRAINMENT OF DRIER AIR ALOFT 
 INTO GUILLERMO CONTINUE TO PRODUCE VERY HOSTILE CONDITIONS FOR THE 
 INNER CORE OF THE TROPICAL STORM. HOWEVER...THE DATA REPORTED BY THE 
 U.S. 53RD WEATHER RECONNAISSANCE SQUADRON AIRCRAFT FLYING INTO 
 GUILLERMO THIS EVENING CONTINUED TO SHOW AN AREA OF VERY STRONG 
 WINDS...NEAR 50 KNOTS...CONFINED TO THE PERSISTENT DEEP CONVECTION 
 LOCATED ABOUT 75 NM NORTHEAST OF THE CENTER. THE ESTIMATED TOPS OF 
 THESE THUNDERSTORMS WERE NEAR 44 THOUSAND FEET. THIS IS LIKELY DUE 
 TO LOCALLY STRONG WINDS UNDERNEATH THE REMAINING POCKET OF DEEP 
 CONVECTION...AS WELL AS THE TIGHT PRESSURE GRADIENT BETWEEN 
 GUILLERMO AND A 1029 MB SURFACE HIGH LOCATED ABOUT 1240 MILES NORTH 
 NORTHEAST OF THE CENTER. THEREFORE...THESE STRONG SURFACE WINDS DO 
 NOT APPEAR TO BE REPRESENTATIVE OF THE INNER CORE WIND FIELD OF 
 GUILLERMO. THE SATELLITE FIX AGENCIES INDICATED GUILLERMO HAS 
 WEAKENED BELOW TROPICAL STORM INTENSITY...WITH JTWC AND SAB 
 INDICATING IT WAS TOO WEAK TO CLASSIFY. SFMR WINDS OF AROUND 42 
 KNOTS WERE FOUND NEAR THE CENTER IN THE NORTHWEST QUADRANT...SO WE 
 WILL MAINTAIN GUILLERMO AS A 45 KNOT TROPICAL STORM FOR THIS 
 ADVISORY.
 
 BASED ON THE LATEST FIXES AND THE AIRCRAFT VORTEX MESSAGES...THE
 INITIAL MOTION IS TOWARD THE WEST-NORTHWEST...OR 285 DEGREES...
 AT 9 KT. NOTE THAT THE TWO AIRCRAFT FIXES AND RECENT MOTION OF THE
 TOTALLY EXPOSED LOW-LEVEL CIRCULATION CENTER...LLCC...SUGGEST THAT
 THE SHORT-TERM MOTION MAY BE EVEN MORE TOWARD THE WEST. HOWEVER...IT
 IS TOO EARLY TO SUGGEST THAT THIS TREND IS MORE THAN A TEMPORARY
 WOBBLE. SO WE WILL MONITOR THE TRACK TONIGHT OF THE LLCC AND
 DETERMINE IF THIS MORE WESTWARD MOTION IS SUSTAINED. IN THE
 MEANTIME...THE FORECAST TRACK WAS ADJUSTED SLIGHTLY TO THE LEFT OF
 THE PREVIOUS FORECAST. NOTE THAT THIS IS TO THE SOUTH OF ALL OF THE
 MAIN TRACK GUIDANCE...INCLUDING THE TVCN CONSENSUS MODEL.
 
 WITH NO SIGNS OF DECREASING VERTICAL WIND SHEAR OR ABATEMENT OF THE
 ENTRAINMENT OF DRY AIR ALOFT...STEADY WEAKENING IS EXPECTED TO
 CONTINUE THROUGH THE END OF THIS WEEK. THE INTENSITY FORECAST
 FOLLOWS THE PREVIOUS ADVISORY...WEAKENING GUILLERMO TO A TROPICAL
 DEPRESSION THURSDAY NIGHT OR FRIDAY. THE WIND RADII FOUND BY THE
 RECONNAISSANCE AIRCRAFT WERE USED TO ADJUST THE SIZE OF THE STORM
 FOR THIS ADVISORY. GUILLERMO IS A VERY ASYMMETRIC TROPICAL
 CYCLONE...SO THE PRIMARY THREAT TO MARINERS REMAINS IN THE NORTHERN
 SEMICIRCLE. NOTE THAT THE COASTAL WATERS NORTHEAST OF THE MAIN
 HAWAIIAN ISLANDS FROM MAUI TO KAUAI REMAIN IN A TROPICAL STORM
 WATCH...SINCE ANY DEVIATION OF THE TRACK TO THE LEFT COULD BRING
 LOCALLY STRONG WINDS TO PORTIONS OF THESE MARINE ZONES.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  06/0900Z 21.8N 153.2W   45 KT  50 MPH
  12H  06/1800Z 22.1N 154.7W   40 KT  45 MPH
  24H  07/0600Z 22.7N 156.9W   35 KT  40 MPH
  36H  07/1800Z 23.3N 159.4W   30 KT  35 MPH
  48H  08/0600Z 24.0N 161.7W   30 KT  35 MPH
  72H  09/0600Z 25.5N 166.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
  96H  10/0600Z...DISSIPATED
  
 $$
 FORECASTER HOUSTON