000
WTNT41 KNHC 280832
TCDAT1

Tropical Storm Erin Discussion Number   7
NWS National Hurricane Center Miami FL       AL062019
500 AM EDT Wed Aug 28 2019

GOES-16 shortwave infrared imagery and recent microwave overpasses
show that Erin's surface center has once again become exposed to the
north of a rather amorphous deep convective mass.  Erin's severely
tilted structure is in response to persistent moderate
west-northwesterly shear, indicated in the UW-CIMSS shear product.
Subjective satellite intensity estimates from TAFB and SAB support
maintaining an initial intensity of 35 kt for this advisory.

A series of microwave images during the past several hours indicate
that the initial motion is estimated to be north-northwestward, or
330/5 kt, within the mid-level southerly flow produced by a
mid-latitude shortwave trough approaching the northeastern United
States, and the Bermuda high to east-southeast.  A turn toward the
north while accelerating is forecast later today and Erin is
expected to reach Nova Scotia, with a north-northeastward heading,
by the end of the week.  Only a minor adjustment, a bit slower than
the previous advisory, was made in order to hedge closer to the TVCA
multi-model consensus.

Statistical-dynamical intensity guidance show that the shear should
diminish somewhat today while the system remains over warm oceanic
sea surface temperatures.  This, should allow for some slight
strengthening at that time.  Thereafter, baroclinic processes
associated with the aforementioned mid-latitude trough and
significantly decreasing sea surface temperatures should cause Erin
to acquire extratropical characteristics, and complete the
transition in 36 hours, as the Florida State Cyclone Phase Evolution
forecast and global models unanimously predict.

Minor adjustments were made to the forecast wind radii based on the
RVCN consensus radii model.


FORECAST POSITIONS AND MAX WINDS

INIT  28/0900Z 32.4N  72.3W   35 KT  40 MPH
 12H  28/1800Z 33.9N  72.2W   40 KT  45 MPH
 24H  29/0600Z 36.6N  70.8W   35 KT  40 MPH
 36H  29/1800Z 40.7N  67.8W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  30/0600Z 45.3N  63.9W   30 KT  35 MPH...POST-TROP/EXTRATROP
 72H  31/0600Z...DISSIPATED

$$
Forecaster Roberts