Hurricane Lorenzo Forecast Discussion Number 35

By | October 1, 2019

Issued at 1100 PM AST Mon Sep 30 2019


000
WTNT43 KNHC 010245
TCDAT3

Hurricane Lorenzo Discussion Number  35
NWS National Hurricane Center Miami FL       AL132019
1100 PM AST Mon Sep 30 2019

Lorenzo has not changed appreciably during the past several hours
on satellite imagery, with an eye still present along with a large
cloud shield in the northeastern quadrant. Dvorak estimates remain
near 90 kt so that will be the initial wind speed.  The initial
wind field has also grown according to the latest scatterometer
data, and that is reflected in the wind radii analyses.

The hurricane is now moving faster and has turned northeastward at
about 17 kt.  Lorenzo should continue to accelerate to the northeast
during the next couple of days ahead of a large mid- latitude
trough, and the model guidance remains in tight agreement taking the
hurricane near the western Azores.  The longer-range future of
Lorenzo is a little clearer tonight as the global models are in much
better agreement on the cyclone turning east- northeastward close to
Ireland and then eastward across Great Britain, dissipating over
western Europe by 96 h. The new forecast is shifted southward, and
is close to a blend of the latest UKMET/ECMWF and GFS solutions.

Lorenzo is forecast to slowly weaken tomorrow due to the cyclone
moving over progressively cooler waters.  Extratropical transition
should occur by 48 hours, and there is unanimous global model
agreement on Lorenzo keeping much of its strength through that time.
Weakening is then anticipated while the low approaches Ireland and
the U.K., although the wind speed forecast at 72 hours is
deceptively low since the radius of maximum winds is possibly
already onshore.

It is also worth mentioning that there will be some enormous seas on
the eastern side of Lorenzo.  The hurricane will be accelerating to
the northeast in the same general direction for a couple of days.
Combined with the large size and intensity, this is a recipe for an
amplified wave field on the eastern side due to a phenomenon called
trapped-wave fetch.  Full information on the High Seas Forecasts can
be found at the Ocean Prediction Center under AWIPS header
NFDHSFAT1, WMO header FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSFAT1.php.
The UK Met Office also has information in High Seas Forecasts issued
by under WMO header FQNT21 EGRR and on the web at
http://www.metoffice.gov.uk/public/weather/marine-high-seas/


Key Messages:

1.  Lorenzo is expected to bring hurricane and tropical storm force
winds to the Azores beginning Tuesday night, and these conditions
will continue into Wednesday.  Hurricane and Tropical Storm Warnings
are in effect for the Azores.

2.  Large swells generated by Lorenzo will continue to spread across
much of the north Atlantic basin during the next few days.  These
swells will produce life-threatening surf and rip currents,
especially across the Azores.


FORECAST POSITIONS AND MAX WINDS

INIT  01/0300Z 32.0N  41.2W   90 KT 105 MPH
 12H  01/1200Z 34.1N  39.0W   90 KT 105 MPH
 24H  02/0000Z 37.8N  34.2W   85 KT 100 MPH
 36H  02/1200Z 42.9N  27.7W   80 KT  90 MPH
 48H  03/0000Z 49.0N  21.0W   75 KT  85 MPH...POST-TROP/EXTRATROP
 72H  04/0000Z 55.0N  10.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 96H  05/0000Z...DISSIPATED

$$
Forecaster Blake

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