Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Mon Oct 9 2017

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on newly formed
Tropical Depression Seventeen, located over the central Atlantic
Ocean more than 800 miles west-southwest of the Azores.

The NOAA Weather Prediction Center is issuing advisories on recently
downgraded Post-Tropical Cyclone Nate, located inland over eastern
Ohio.

Tropical cyclone formation is not expected during the next 5 days.

&&
Public Advisories on Tropical Depression Seventeen are issued under
WMO header WTNT32 KNHC and under AWIPS header MIATCPAT2.
Forecast/Advisories on Tropical Depression Seventeen are issued
under WMO header WTNT22 KNHC and under AWIPS header MIATCMAT2.

$$
Forecaster Stewart

TROPICAL DEPRESSION FORMS OVER THE EASTERN ATLANTIC… …NO THREAT TO LAND

Tropical Depression Seventeen Discussion Number 1
NWS National Hurricane Center Miami FL AL172017
500 AM AST Mon Oct 09 2017

The well-defined low pressure system over the eastern Atlantic
several hundred miles southwest of the Azores has maintained an
area of deep convection near and to the east of the center for the
past several hours. Therefore, the system now meets the criteria
for a tropical depression. The initial intensity is estimated to be
30 kt based on ASCAT data from around 0000 UTC and a 2.0/30 kt
Dvorak classification from TAFB.

The depression is moving slowly northward at 3 kt, and a continued
slow north to north-northeast motion is expected today. A turn to
the east and then southeast is forecast to begin tonight and
continue through Wednesday while the cyclone is steered by the flow
on the east side of a subtropical ridge. Thereafter, a mid- to
upper-level trough is expected to approach the depression, and that
should cause the system to move a little faster to the east and
east-northeast. The NHC track forecast lies near the middle of the
guidance envelope, in agreement with various consensus aids, and
keeps the system far from any land areas.

The depression is currently over marginally warm 27 deg C SSTs and
in an environment of moderate to strong westerly shear. The
models suggest that the shear will likely let up a little during the
next couple of days, which could allow the depression to gradually
strengthen while it remains over relatively warm waters. After that
time, the shear could increase again, but the amount of shear
depends on the exact track of the tropical cyclone. There is a fair
amount of spread in the models at the longer range with the regional
models (HWRF, HMON, and COAMPS-TC) bringing the system to hurricane
strength while the statistical SHIPS and LGEM models show a much
weaker system. The NHC intensity forecast leans toward the more
conservative side of the guidance for now, but it should be noted
that confidence in the intensity forecast is low.

FORECAST POSITIONS AND MAX WINDS

INIT 09/0900Z 31.1N 39.9W 30 KT 35 MPH
12H 09/1800Z 31.5N 39.8W 35 KT 40 MPH
24H 10/0600Z 31.7N 39.0W 35 KT 40 MPH
36H 10/1800Z 31.5N 38.4W 40 KT 45 MPH
48H 11/0600Z 31.0N 37.8W 45 KT 50 MPH
72H 12/0600Z 29.7N 37.0W 50 KT 60 MPH
96H 13/0600Z 29.7N 35.5W 50 KT 60 MPH
120H 14/0600Z 31.0N 32.0W 50 KT 60 MPH

$$
Forecaster Cangialosi

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Mon Oct 9 2017

For the eastern North Pacific…east of 140 degrees west longitude:

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Zelinsky