000
WTNT43 KNHC 052044
TCDAT3

TROPICAL STORM BERTHA DISCUSSION NUMBER  20
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032014
500 PM EDT TUE AUG 05 2014

Deep convection redeveloped over the center earlier today, but
that convection was subsequently sheared off to the east-northeast.
An ASCAT overpass from a few hours ago indicated that, although
Bertha still had a well-defined surface circulation, the maximum
winds were no more than 45 kt, Based on this, and a Dvorak
classification of T3.0 from TAFB, the advisory intensity is
set at 45 kt. The scatterometer data also indicated that there
were no winds to tropical storm force over the western semicircle of
the circulation.  The SHIPS model predicts that west-southwesterly
shear will increase greatly over the next day or two, and these
conditions could cause more weakening than indicated by the
official forecast.  However, it is possible that the system may
maintain more of its intensity by extracting energy from baroclinic
processes associated with the frontal system just to its north.  In
any event, global models show the system becoming embedded within
the frontal zone within 36 hours, so the official forecast indicates
that the transition to a post-tropical/extratropical cyclone will
be complete by that time.

Bertha's heading is gradually shifting to the right and the motion
is now 030/18 kt.  There is little change to the track forecast
philosophy.  Over the next couple of days, the tropical, or
post-tropical, cyclone should turn toward the northeast and
accelerate ahead of an amplifying mid-level trough moving off the
northeast United States coast.  Later in the forecast period, the
system should move swiftly east-northeastward to eastward in the
mid-latitude westerlies over the North Atlantic.

The track and wind radii forecast for 36 hours and beyond have been
coordinated with the NOAA Ocean Prediction Center.

FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 36.2N  70.3W   45 KT  50 MPH
 12H  06/0600Z 38.2N  67.0W   45 KT  50 MPH
 24H  06/1800Z 41.0N  61.6W   40 KT  45 MPH
 36H  07/0600Z 43.7N  55.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  07/1800Z 46.0N  49.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  08/1800Z 48.0N  37.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  09/1800Z 49.0N  20.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
120H  10/1800Z 51.0N   1.0W   30 KT  35 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch