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Tropical Storm Helene Discussion Number  34
NWS National Hurricane Center Miami FL       AL082018
500 PM AST Sat Sep 15 2018

The cloud pattern of Helene is gradually decaying and transitioning
to a shear pattern, with the low-level center occasionally visible
through breaks in the cirrus overcast.  The initial intensity is
reduced to 55 kt in best agreement with the CIMSS satellite
consensus.  Helene is moving toward colder water and into increasing
shear associated with the mid-latitude westerlies.  This should
cause continued weakening and, as Helene merges with a frontal
system, extratropical transition in about 36 h.  The forecast will
continue to call for Helene or its remnants to be absorbed into a
large non-tropical low over the North Atlantic between 72-96 h, and
the latest global model guidance suggests this could happen earlier
than forecast.

The initial motion is now 050/19.  A mostly northeastward motion at
a faster forward speed should occur during the remainder of the
cyclone's life as it becomes more embedded in the westerlies.  On
the forecast track, Helene should pass near or over the western
Azores during the next several hours, and head toward Ireland and
the United Kingdom Sunday night and Monday.  There are again no
significant changes to either the track guidance or the official
forecast track since the last advisory.

Tropical storm conditions are spreading over portions of the Azores
and should continue through tonight.

Helene is also expected to be a storm-force post-tropical cyclone
when it approaches Ireland and the United Kingdom in two to three
days.  Interests in those locations should consult products from
their local meteorological service for information about potential
impacts from Helene.  Local forecasts and warnings for the UK can be
found on the website of the UK Met Office at
https://www.metoffice.gov.uk/.  Local forecasts and warnings for
Ireland can be found on the website of Met Eireann at
https://www.met.ie/.


FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 40.2N  32.1W   55 KT  65 MPH
 12H  16/0600Z 41.9N  29.2W   55 KT  65 MPH
 24H  16/1800Z 44.4N  24.1W   55 KT  65 MPH
 36H  17/0600Z 47.2N  17.9W   55 KT  65 MPH...POST-TROP/EXTRATROP
 48H  17/1800Z 51.2N  11.1W   50 KT  60 MPH...POST-TROP/EXTRATROP
 72H  18/1800Z 61.0N   1.0E   50 KT  60 MPH...POST-TROP/EXTRATROP
 96H  19/1800Z...ABSORBED BY EXTRATROPICAL LOW

$$
Forecaster Beven

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