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Tropical Storm Ernesto Discussion Number   7
NWS National Hurricane Center Miami FL       AL052018
500 PM AST Thu Aug 16 2018

Visible and infrared satellite imagery shows that convective
banding has increased closer to the center of Ernesto today.  The
system has also lost much of its outer cloud bands and is no longer
co-located with an upper-level low.  On this basis, Ernesto is now
being classified as a tropical storm. The initial intensity remains
40 kt, which is based on recent satellite estimates and the earlier
ASCAT data.  Although the cyclone is forecast to move over cooler
waters and become post-tropical very soon, the global models deepen
the system somewhat due to baroclinic processes. In addition, the
expected increase in the cyclone's forward speed is likely to result
in an increase in the wind speed.  The new NHC intensity forecast
calls for slight strengthening over the next 12-24 hours, with
little overall change in intensity thereafter.  The system is still
predicted to merge with a frontal zone as it approaches Ireland and
the United Kingdom late Saturday or Saturday night.

Ernesto continues to accelerate northeastward and is now moving
045/16 kt.  The cyclone should accelerate further while moving
northeastward to east-northeastward within the mid-latitude
westerlies over the next day or two. The dynamical model guidance
remains tightly clustered and little change was made to the
previous NHC track forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  16/2100Z 43.0N  41.0W   40 KT  45 MPH
 12H  17/0600Z 44.9N  37.6W   45 KT  50 MPH...POST-TROPICAL
 24H  17/1800Z 47.7N  31.4W   45 KT  50 MPH...POST-TROPICAL
 36H  18/0600Z 50.2N  23.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  18/1800Z 52.0N  15.8W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  19/1800Z...MERGED WITH FRONTAL ZONE

$$
Forecaster Brown

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