000
WTNT42 KNHC 132027
TCDAT2
TROPICAL STORM BERTHA DISCUSSION NUMBER  43
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL022008
500 PM EDT SUN JUL 13 2008
 
AN AIR FORCE RESERVE RECONNAISSANCE PLANE JUST FINISHED TWO PASSES
ACROSS BERTHA. FLIGHT-LEVEL WINDS...SFMR AND DROPSONDES INDICATE
THAT BERTHA CONTINUES AS A 55 KT TROPICAL STORM. HIGH RESOLUTION
SATELLITE IMAGES SHOW A VIGOROUS LOW-LEVEL CIRCULATION ASSOCIATED
WITH THE CYCLONE BUT DEEP CONVECTION IS VERY LIMITED. SOME OF THE
DYNAMICAL MODELS INDICATE RESTRENGTHENING WHILE THE SHIPS GUIDANCE
MAINTAIN BERTHA WITH BASICALLY THE SAME INTENSITY.  THE OFFICIAL
FORECAST KEEPS BERTHA AS A 50 KT CYCLONE THROUGH FIVE DAYS....AS
INDICATED BY THE SHIPS MODEL. SOME INTENSIFICATION COULD OCCUR IF
BERTHA BEGINS TO ACQUIRE EXTRATROPICAL CHARACTERISTICS AS IT
INTERACTS WITH THE MID-LATITUDE WESTERLIES.  

BERTHA FOOLED ME ONCE AGAIN. IT APPEARS THAT BERTHA BEGAN A
NORTHWESTWARD DRIFT EARLIER TODAY BUT...IN FACT...IT WAS MOVING IN
CIRCLES AND IT COULD BE DOING ONE OF THESE LOOPS AGAIN. MODEL
GUIDANCE...WHICH IS NOW MORE IN GOOD AGREEMENT...INSISTS THAT
THE NORTHWARD MOTION SHOULD BEGIN TONIGHT AND SO DOES THE OFFICIAL
FORECAST. IN ABOUT 48 HOURS...BERTHA IS EXPECTED TO BE EMBEDDED
WITHIN THE MID-LATITUDE WESTERLIES AND BE STEERED SLOWLY EASTWARD.
THE CIRCULATION SHOULD THEN EXPAND WHILE GRADUALLY ACQUIRING
EXTRATROPICAL CHARACTERISTICS.  ONE WAY OR ANOTHER IT APPEARS THAT
BERTHA COULD BE WITH US FOR SEVERAL MORE DAYS.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/2100Z 30.2N  63.1W    55 KT
 12HR VT     14/0600Z 30.5N  63.3W    50 KT
 24HR VT     14/1800Z 32.0N  63.8W    50 KT
 36HR VT     15/0600Z 33.5N  63.7W    50 KT
 48HR VT     15/1800Z 35.0N  62.5W    50 KT
 72HR VT     16/1800Z 35.5N  60.0W    50 KT
 96HR VT     17/1800Z 35.0N  57.0W    50 KT
120HR VT     18/1800Z 35.0N  54.0W    50 KT
 
$$
FORECASTER AVILA