Bertha remains a tricky system to say the least.... a part of the 5am Discussion...

BERTHA'S FORWARD MOTION HAS SLOWED A BIT AND IS NOW ABOUT 315/8. AN
ANTICYCLONE TO THE NORTH OF THE HURRICANE WILL CONTINUE TO SLIDE
EASTWARD OVER THE NEXT DAY OR TWO...SO THE TRACK OF THE HURRICANE
IS LIKELY TO BEND TOWARD THE NORTH THROUGH 48 HOURS. BEYOND THAT
TIME...THE TRACK FORECAST IS COMPLICATED BY THE FACT THAT THE
DYNAMICAL MODELS...IN PARTICULAR THE GFS...SHOW A MID-LEVEL
ANTICYCLONE DEVELOPING TO THE NORTH OF BERTHA IN AROUND 72 HOURS.
THIS DEVELOPMENT WOULD AT LEAST RETARD THE NORTHWARD PROGRESS OF
THE HURRICANE AND...IF THE ANTICYCLONE TURNS OUT TO BE STRONG
ENOUGH...COULD EVEN FORCE A TURN TO THE LEFT AS INDICATED BY THE
GFS. THE GFDL AND HWRF MODELS RESPOND TO THE INCREASED RIDGING
MAINLY BY SLOWING THE TROPICAL CYCLONE AS IT CROSSES 30N LATITUDE.
IT IS CERTAINLY POSSIBLE FOR BERTHA TO MOVE ERRATICALLY IN ABOUT 3
DAYS...BUT THE DETAILS OF THAT MOTION ARE OF COURSE UNKNOWN.