506 
 WTNT45 KNHC 151440
 TCDAT5
  
 TROPICAL STORM ERIN DISCUSSION NUMBER   3
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052013
 1100 AM AST THU AUG 15 2013
  
 THE SATELLITE PRESENTATION OF THE CYCLONE HAS CONTINUED TO IMPROVE
 OVER THE PAST FEW HOURS. INFRARED IMAGERY SHOWS VERY COLD CLOUD
 TOPS SITUATED NEAR AND TO THE SOUTH OF THE ESTIMATED CENTER
 POSITION...WITH A SMALL BANDING FEATURE EXTENDING TO THE SOUTHWEST.
 THE INITIAL INTENSITY OF 35 KT IS SUPPORTED BY A BLEND OF THE
 LATEST OBJECTIVE AND SUBJECTIVE DVORAK ESTIMATES AND A 1102 UTC
 ASCAT-A PASS THAT SHOWED WINDS OF 32 KT. ERIN IS EXPECTED TO BE IN
 AN ENVIRONMENT THAT SUPPORTS SOME STRENGTHENING DURING THE NEXT
 COUPLE OF DAYS WITH SSTS OF 26-27C...LOW SHEAR...AND A MOIST
 ENVIRONMENT. BY DAY 3...THE SYSTEM WILL BE MOVING INTO A DRIER AND
 MORE STABLE ATMOSPHERIC ENVIRONMENT...WHICH SHOULD RESULT IN
 WEAKENING. THE GLOBAL MODELS AND THE HWRF SHOW A WEAK OR
 DISSIPATING SYSTEM BY DAY 5...HOWEVER THE SHIPS AND LGEM SHOW
 LITTLE CHANGE IN INTENSITY OR EVEN STRENGTHENING. THE OFFICIAL
 FORECAST LEANS A LITTLE TOWARD THE WEAKER SOLUTION AT DAYS 4 AND 5.
  
 THE AFOREMENTIONED ASCAT PASS WAS ALSO HELPFUL IN LOCATING THE
 CENTER OF ERIN...WHICH IS A LITTLE SOUTH AND WEST OF PREVIOUS
 ESTIMATES. BASED ON A SOUTHWESTWARD ADJUSTMENT OF THE CENTER
 POSITION THE INITIAL MOTION ESTIMATE IS 285/13. ERIN IS CURRENTLY
 BEING STEERED BY A NARROW SUBTROPICAL RIDGE TO ITS NORTH...AND THE
 GUIDANCE IS IN GOOD AGREEMENT ON THIS MOTION CONTINUING FOR THE
 NEXT COUPLE OF DAYS. BY DAY 3...THE SPREAD IN THE GUIDANCE
 INCREASES. ON THE RIGHT SIDE OF THE GUIDANCE ENVELOPE THE GFDL...
 GFDL ENSEMBLE MEAN...ECMWF AND UKMET SHOW A NORTHWESTWARD OR
 WEST-NORTHWESTWARD MOTION. THE FIM...GFS...GFS ENSEMBLE MEAN AND
 HWRF ALL SHOW A WESTWARD TRACK...CONSISTENT WITH A SHALLOWER SYSTEM
 BEING STEERED BY THE LOW-LEVEL FLOW. THE NHC FORECAST AT DAYS 3
 THROUGH 5 CONTINUES TO FOLLOW THIS SOUTHERN CAMP OF MODELS AND IS
 LARGELY AN UPDATE OF THE PREVIOUS NHC TRACK.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  15/1500Z 14.4N  26.5W   35 KT  40 MPH
  12H  16/0000Z 15.0N  28.6W   40 KT  45 MPH
  24H  16/1200Z 15.7N  31.2W   45 KT  50 MPH
  36H  17/0000Z 16.7N  33.5W   45 KT  50 MPH
  48H  17/1200Z 17.4N  35.8W   50 KT  60 MPH
  72H  18/1200Z 18.0N  40.0W   50 KT  60 MPH
  96H  19/1200Z 18.0N  44.5W   45 KT  50 MPH
 120H  20/1200Z 18.0N  49.0W   35 KT  40 MPH
  
 $$
 FORECASTER BRENNAN