102 
 WTNT42 KNHC 062057
 TCDAT2
 TROPICAL STORM BERTHA DISCUSSION NUMBER  15
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL022008
 500 PM EDT SUN JUL 06 2008
  
 A COUPLE OF MICROWAVE IMAGES JUST RECEIVED SUGGEST THAT BERTHA'S
 VORTEX IS TILTED A LITTLE.  THE IMAGES INDICATE THAT THE
 LOW-LEVEL CENTER IS LOCATED JUST SOUTHWEST OF THE MID-LEVEL CENTER.
 HOWEVER...THESE IMAGES ALSO SUGGEST THAT THE OVERALL STRUCTURE HAS
 IMPROVED WITH THE APPEARANCE OF AN EYE FEATURE...SUGGESTING THAT
 BERTHA IS STRENGTHENING.  DVORAK INTENSITY ESTIMATES WERE 45 KT AT
 18Z...BUT WITH THE IMPROVING STRUCTURE THE INITIAL INTENSITY IS
 INCREASED TO 50 KT. CONDITIONS APPEAR CONDUCIVE FOR STRENGTHENING
 DURING THE NEXT COUPLE OF DAYS AND BERTHA COULD BECOME A HURRICANE. 
 HOWEVER...INDICATIONS ARE THAT BEYOND 48 HOURS...WESTERLY SHEAR
 COULD HALT ANY ADDITIONAL STRENGTHENING AS SUGGESTED BY THE SHIPS
 MODELS.
  
 BERTHA IS MOVING WEST-NORTHWESTWARD OR 285/17 KT.  ALL OF THE
 AVAILABLE GUIDANCE SHOWS A NORTHWEST TURN AS THE RIDGE OVER THE
 WESTERN ATLANTIC WEAKENS IN A FEW DAYS. HOWEVER...THERE REMAINS
 SOME SPREAD IN THE GUIDANCE AS TO WHEN THE TURN OCCURS.  THE HWRF
 AND GFDL...WHICH DEPICT A STRONG TROPICAL CYCLONE REMAINS ALONG
 THE EASTERN EDGE OF THE MODEL ENVELOPE.  THE UKMET WHICH KEEPS
 BERTHA WEAKER IS ALONG THE WESTERN EDGE. THE NEW TRACK
 FORECAST IS ADJUSTED SLIGHTLY EASTWARD...BUT STILL REMAINS
 WEST OF THE MODEL CONSENSUS.
   
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      06/2100Z 18.1N  47.0W    50 KT
  12HR VT     07/0600Z 18.7N  49.6W    55 KT
  24HR VT     07/1800Z 19.5N  52.3W    60 KT
  36HR VT     08/0600Z 20.2N  54.6W    65 KT
  48HR VT     08/1800Z 20.9N  56.7W    70 KT
  72HR VT     09/1800Z 23.0N  60.5W    70 KT
  96HR VT     10/1800Z 26.0N  64.0W    70 KT
 120HR VT     11/1800Z 29.0N  65.5W    70 KT
  
 $$
 FORECASTER BROWN
  
 
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