472 
 WTNT42 KNHC 081440
 TCDAT2
 HURRICANE BERTHA DISCUSSION NUMBER  22
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL022008
 1100 AM EDT TUE JUL 08 2008
  
 CONVENTIONAL AND MICROWAVE IMAGERY SHOW A RAPID DEGRADATION OF
 BERTHA'S STRUCTURE DURING THE LAST 6 HOURS.  THE EYE HAS
 DISAPPEARED AND CLOUD TOPS HAVE WARMED CONSIDERABLY.  THERE IS ALSO
 EVIDENCE IN MICROWAVE IMAGERY THAT THE WESTERN PORTION OF THE
 EYEWALL HAS ERODED.  A BLEND OF THE FINAL T AND CI NUMBERS FROM THE
 DVORAK TECHNIQUE SUPPORTS AN INITIAL INTENSITY OF 90 KT AND LATEST
 OBJECTIVE T NUMBERS SUGGEST AN EVEN LOWER INTENSITY.  THE INITIAL
 INTENSITY IS CONSERVATIVELY SET AT 90 KT.  IT WOULD APPEAR THAT
 BERTHA HAS FINALLY ENCOUNTERED THE HIGHER SHEAR ENVIRONMENT WE'VE
 BEEN FORECASTING.  ADDITIONALLY...THE CYCLONE IS MOVING OVER
 SLIGHTLY COOLER WATERS AND THERE ARE SOME INDICATIONS IN SATELLITE
 IMAGERY THAT IT COULD BE ENTRAINING DRY AIR.  BOTTOM LINE...THE
 ENVIRONMENT LOOKS RATHER HOSTILE AND BERTHA SHOULD CONTINUE TO
 WEAKEN IN THE SHORT-TERM.  TOWARDS THE END OF THE FORECAST
 PERIOD...THE SHEAR COULD RELAX AND SSTS INCREASE SO THERE IS SOME
 POTENTIAL FOR A LITTLE RE-INTENSIFICATION.  HOWEVER...GIVEN THE
 UNCERTAINTY IN INTENSITY FORECASTING...THE OFFICIAL FORECAST MERELY
 SHOWS SLOW WEAKENING THROUGH THE FORECAST PERIOD AND IS IN GOOD
 AGREEMENT WITH A CONSENSUS OF THE VARIOUS INTENSITY MODELS. 
  
 BERTHA HAS BEEN MOVING A LITTLE TO THE RIGHT OF THE PREVIOUS
 ESTIMATE OR 315/9.  BERTHA SHOULD CONTINUE TO GRADUALLY TURN
 NORTHWARD OVER THE NEXT COUPLE OF DAYS AS A MID-LEVEL RIDGE OVER
 THE WESTERN ATLANTIC WEAKENS AND IS REPLACED BY A WEAK TROUGH. 
 SINCE THE STEERING CURRENTS COULD BECOME RATHER WEAK AS A RESULT OF
 THIS EVOLUTION...BERTHA COULD MOVE SLOWLY AND ERRATICALLY
 TOWARDS THE END OF THE FORECAST.  IT IS FOR THIS REASON THAT
 INTERESTS IN BERMUDA SHOULD CONTINUE TO MONITOR THE PROGRESS OF
 THIS SYSTEM. TRACK MODELS HAVE NOT CHANGED SIGNIFICANTLY SINCE THE
 LAST FORECAST SO ONLY COSMETIC CHANGES TO THE OFFICIAL TRACK
 FORECAST ARE NEEDED AT THIS TIME.   
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      08/1500Z 22.1N  53.8W    90 KT
  12HR VT     09/0000Z 23.1N  54.9W    85 KT
  24HR VT     09/1200Z 24.3N  56.4W    80 KT
  36HR VT     10/0000Z 25.5N  57.8W    80 KT
  48HR VT     10/1200Z 26.6N  58.7W    75 KT
  72HR VT     11/1200Z 28.5N  59.5W    70 KT
  96HR VT     12/1200Z 30.5N  59.5W    65 KT
 120HR VT     13/1200Z 32.5N  58.5W    65 KT
  
 $$
 FORECASTER RHOME
  
 
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