955 
 WTNT42 KNHC 311457
 TCDAT2
 HURRICANE EARL DISCUSSION NUMBER  25
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
 1100 AM AST TUE AUG 31 2010
  
 THE EYE HAS BECOME OBSCURED ON VISIBLE IMAGES AND THIS IS REFLECTED
 IN A DECREASE IN THE DVORAK NUMBERS AND IN AN INCREASE IN THE
 PRESSURE TO 939 MB. THIS APPARENT WEAKENING IS MOST LIKELY RELATED
 TO AN ONGOING EYEWALL REPLACEMENT CYCLE AS INDICATED BY THE DOUBLE
 EYE STRUCTURE OBSERVED ON MICROWAVE DATA AT 1035 UTC. HOWEVER...AN
 AVERAGE OF THE FLIGHT-LEVEL WINDS AND SFMR DATA FROM THE AIR FORCE
 RECONNAISSANCE PLANE STILL SUPPORTS AN INITIAL INTENSITY OF 115
 KNOTS. NO CHANGE IN INTENSITY IS EXPECTED TODAY BUT THERE IS A
 CHANCE FOR EARL TO STRENGTHEN A LITTLE DURING THE NEXT 24 HOURS IF
 THE OUTER EYEWALL SHRINKS. DESPITE THE FLUCTUATIONS IN INTENSITY...
 EARL MOST LIKELY WILL RETAIN CATEGORY FOUR STATUS FOR THE NEXT 48
 HOURS. A GRADUAL WEAKENING SHOULD BEGIN THEREAFTER AS THE SHEAR
 INCREASES.
  
 EARL HAS CONTINUED TO WOBBLE DURING THE PAST FEW HOURS BUT THE
 AVERAGE MOTION IS TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT 12
 KNOTS. EARL HAS BEEN STEERED BY THE FLOW AROUND A SUBTROPICAL RIDGE
 EXTENDING FROM THE EASTERN UNITED STATES EASTWARD ACROSS THE
 ATLANTIC. THIS PATTERN WILL KEEP EARL ON A GENERAL WEST-NORTHWEST
 TO NORTHWEST TRACK DURING THE NEXT 24 TO 48 HOURS. THEREAFTER...THE
 SUBTROPICAL RIDGE WILL MOVE EAST AND EARL WILL LIKELY TURN NORTH AND
 NORTHEAST BETWEEN THE RIDGE AND MID-LEVEL TROUGH OVER THE EASTERN
 UNITED STATES. THIS IS THE SCENARIO PROVIDED BY MOST OF THE
 DYNAMICAL MODELS. THE OFFICIAL FORECAST HAS SHIFTED A LITTLE TO THE
 WEST BEFORE 48 HOURS AND IS ON THE WESTERN EDGE OF THE GUIDANCE
 ENVELOPE.
  
 GIVEN THE TRACK AND THE LARGE AREA OF TROPICAL STORM FORCE WINDS...A
 HURRICANE WATCH WILL LIKELY BE REQUIRED FOR A PORTION OF THE
 MID-ATLANTIC COAST LATER TODAY. INTERESTS FROM THE CAROLINAS
 NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE PROGRESS OF EARL.
 THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO HOW CLOSE THE
 HURRICANE WILL COME TO THE U.S. EAST COAST.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      31/1500Z 21.2N  67.9W   115 KT
  12HR VT     01/0000Z 22.3N  69.7W   115 KT
  24HR VT     01/1200Z 24.8N  71.7W   120 KT
  36HR VT     02/0000Z 27.3N  73.5W   115 KT
  48HR VT     02/1200Z 30.5N  75.0W   115 KT
  72HR VT     03/1200Z 36.5N  73.0W   100 KT
  96HR VT     04/1200Z 43.5N  66.0W    80 KT
 120HR VT     05/1200Z 52.5N  57.0W    55 KT...POST-TROP/EXTRATROP
  
 $$
 FORECASTER AVILA