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 973 
 WTPA44 PHFO 171451
 TCDCP4
 
 TROPICAL STORM PEWA DISCUSSION NUMBER   5
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP012013
 500 AM HST SAT AUG 17 2013
  
 THE DEEP CONVECTION NEAR THE CORE OF PEWA...PRONOUNCED /PEH-VAH/...
 HAS BEEN PULSING OVERNIGHT. THE RAINBAND STRUCTURE THAT HAD BEEN
 WEST OF THE CENTRAL DEEP CONVECTION HAS FADED...BUT THE UPPER LEVEL
 OUTFLOW PATTERN APPEARS TO BE IMPROVING. THE SATELLITE FIX AGENCIES
 AT PHFO...JTWC AND SAB ALL SHOWED THE CURRENT INTENSITY IS 3.5.
 THERE WAS ALSO AN ASCAT PASS AT 0936Z WHICH SHOWED A FEW WINDS NEAR
 45 KT. WITH THE IMPROVED APPEARANCE IN SATELLITE IMAGERY...THE
 SUBJECTIVE DVORAK INTENSITY AND THE ASCAT DATA...WE HAVE ESTIMATED
 THE INITIAL INTENSITY HAS INCREASED TO NEAR 50 KT.
  
 THERE IS STILL SOME DOUBT ABOUT THE LOCATION OF THE CLOUD SYSTEM 
 CENTER AS OPPOSED TO THE LOW-LEVEL CIRCULATION CENTER /LLCC/ BASED 
 ON AN ASCAT PASS FROM 0936Z. THE RECENT MICROWAVE PASSES ALSO HAVE 
 NOT BEEN VERY USEFUL IN LOCATING THE LLCC. SO THERE IS UNCERTAINTY 
 IN THE EXACT LOCATION OF THE CENTER OF PEWA TONIGHT. THE CURRENT 
 MOTION IS 290/11 SINCE PEWA IS BEING STEERED BY THE DEEP LAYER FLOW 
 AROUND HIGH PRESSURE LOCATED FAR NORTH OF THE AREA. THE FORECAST 
 MODELS SHOW THIS HIGH PRESSURE WILL BUILD WESTWARD...WHICH IS 
 EXPECTED TO KEEP PEWA ON A GENERAL WEST NORTHWEST TRACK INTO EARLY 
 NEXT WEEK. THE LATEST CONSENSUS OF THE DYNAMICAL MODELS HAS SHIFTED 
 NORTHWARD...AND THE CURRENT FORECAST HAS BEEN NUDGED SLIGHTLY TO THE 
 RIGHT OF THE PREVIOUS TRACK TO MORE CLOSELY FOLLOW THIS GUIDANCE.
  
 THE INTENSITY FORECAST CONTINUES TO REMAIN VERY CHALLENGING. 
 ENVIRONMENTAL CONDITIONS APPEAR TO BE CONDUCIVE FOR FURTHER 
 INTENSIFICATION OF PEWA DURING THE NEXT 36 TO 48 HOURS. THE FORECAST 
 TRACK IS OVER WARM SSTS OF AT LEAST 28C AND THE VERTICAL WIND SHEAR 
 IS EXPECTED TO REMAIN RELATIVELY LOW. THE FORECAST PATH IS ALSO OVER 
 GREATER OCEANIC HEAT CONTENT VALUES. HOWEVER...PEWA MAY EVENTUALLY 
 BE IMPACTED BY THE CIRCULATION AROUND AN UPPER LEVEL LOW CURRENTLY 
 NEAR 21N 174E. THE LATEST INTENSITY FORECAST ASSUMES PEWA CAN 
 INTENSIFY TO A TYPHOON IN THE NORTHWEST PACIFIC OCEAN WITHIN THE 
 NEXT 36 TO 72 HOURS. AFTER THAT IS ASSUMED THAT THE INFLUENCE OF THE 
 UPPER LEVEL LOW WILL KEEP IT FROM INTENSIFYING FURTHER DURING DAYS 4 
 AND 5. NOTE THAT THE INITIAL WIND RADII WERE ADJUSTED BASED ON THE 
 LATEST ASCAT PASS.
  
 FINALLY...THE CENTER OF PEWA IS FORECAST TO CROSS THE INTERNATIONAL
 DATE LINE INTO THE AREA OF RESPONSIBILITY OF RSMC TOKYO LATER THIS
 WEEKEND. BASED ON THE LATEST TRACK...PEWA MAY MAKE THIS CROSSING
 AROUND 18/0600Z...BUT IT IS TOO EARLY TO MAKE THIS DETERMINATION
 YET.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  17/1500Z 10.7N 177.3W   50 KT  60 MPH
  12H  18/0000Z 11.4N 179.0W   55 KT  65 MPH
  24H  18/1200Z 12.4N 179.0E   60 KT  70 MPH
  36H  19/0000Z 13.7N 176.9E   65 KT  75 MPH
  48H  19/1200Z 14.9N 174.7E   70 KT  80 MPH
  72H  20/1200Z 17.5N 170.0E   70 KT  80 MPH
  96H  21/1200Z 20.5N 165.5E   70 KT  80 MPH
 120H  22/1200Z 23.0N 161.0E   70 KT  80 MPH
  
 $$
 FORECASTER HOUSTON
  
 
 
 
 
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