Tropical Storm BERTHA

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TROPICAL STORM BERTHA DISCUSSION NUMBER  19
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032014
1100 AM EDT TUE AUG 05 2014

Increasing westerly vertical shear is displacing deep convection to
the east of the low-level center of Bertha, which is clearly exposed
in visible satellite images.  The current intensity is adjusted down
a bit in accordance with observations from a NOAA Hurricane Hunter
plane a few hours ago.  Since the shear is forecast to become even
stronger over the next couple of days, additional weakening would be
expected due to those conditions. However, the cyclone might be able
to draw energy from baroclinic process associated with a frontal
zone not far to its north, and maintain at least some of its
intensity.  The system is forecast to merge with that front and
become an extratropical cyclone within 36 hours. It is also
possible, however, that the shear will become so strong that Bertha
would be reduced to a convection-free post-tropical cyclone before
extratropical transition takes place. The NOAA Ocean Prediction
Center has provided input to the official intensity forecast.

Bertha continues moving north-northeastward near 19 kt.  The
tropical, or post-tropical, cyclone is forecast to accelerate
northeastward ahead of an amplifying mid-level trough near the
United States east coast during the next couple of days. Thereafter,
the system should move quickly east-northeastward to eastward in the
mid-latitude westerlies over the North Atlantic. The track forecast
for 36 hours and beyond is also based on input from the Ocean
Prediction Center.

FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 34.8N  71.9W   50 KT  60 MPH
 12H  06/0000Z 37.1N  69.2W   50 KT  60 MPH
 24H  06/1200Z 39.8N  64.5W   50 KT  60 MPH
 36H  07/0000Z 42.5N  59.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
 48H  07/1200Z 45.0N  53.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  08/1200Z 49.0N  40.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  09/1200Z 49.0N  22.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  10/1200Z 51.0N   2.0W   45 KT  50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch

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