...TROPICAL DEPRESSION FORMS OVER THE EASTERN ATLANTIC... ...NO THREAT TO LAND... As of 5:00 AM EST Mon Oct 9 the center of Seventeen was located near 31.1, -39.9 with movement N at 3 mph. The minimum central pressure was 1008 mb with maximum sustained winds of about 35 mph.
[caption id="" align="aligncenter" width="600" ] Current Track of Tropical Depression Seventeen [/caption]
[caption id="" align="aligncenter" width="600" ]Probability of Tropical Force Winds for Tropical Depression Seventeen [/caption]
WATCHES AND WARNINGS
-------------------- There are no coastal watches or warnings in effect.
DISCUSSION AND 48-HOUR OUTLOOK
------------------------------ At 500 AM EST (0900 UTC), the center of Tropical Depression Seventeen was located near latitude 31.1 North, longitude 39.9 West. The depression is moving toward the north near 3 mph (6 km/h), and this motion is expected to continue today. A turn to the east and east-southeast is expected to occur tonight and Tuesday.
Maximum sustained winds are near 35 mph (55 km/h) with higher gusts. Some strengthening is forecast, and the depression is expected to become a tropical storm later today or tonight.
The estimated minimum central pressure is 1008 mb (29.77 inches).
HAZARDS AFFECTING LAND
---------------------- None.
NEXT ADVISORY
------------- Next complete advisory at 1100 AM EST.
IN DEPTH DISCUSSION
500 AM EST 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.
Current Track of Tropical Depression Seventeen [/caption]
Probability of Tropical Force Winds for Tropical Depression Seventeen [/caption]