ATL: ISAAC - Post-Tropical - Discussion

[Gustywind]

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
200 PM EDT Fri Sep 7 2018


Satellite data indicate that the circulation of a low pressure system located about 700 miles west of the Cabo Verde Islands
is well defined. However, the associated shower and thunderstorm activity has not been sufficiently organized to designate the
system as a tropical depression. Only a slight increase in organization would lead to the initiation of advisories on this
system, possibly as early as later today or tonight. This low is expected to move slowly westward across the tropical Atlantic Ocean
during the next several days.The chance of this system becoming a tropical cyclone during the next 48 hours is now in the high
range.

[Gustywind]

Latest from SSD...

07/1745 UTC 13.6N 34.9W T1.0/1.0 92L

[WAcyclone]

 https://twitter.com/ToddKimberlain/status/1038148669210587136



 https://twitter.com/ToddKimberlain/status/1038149076838178819

[bamajammer4eva]

 https://twitter.com/NHC_Atlantic/status/1038158625993310208

[cycloneye]

NHC will initiate advisories at 5 PM AST on Tropical Depression Nine, located over the eastern tropical Atlantic Ocean.

[cycloneye]

BULLETIN
Tropical Depression Nine Advisory Number 1
NWS National Hurricane Center Miami FL AL092018
500 PM AST Fri Sep 07 2018

...TROPICAL DEPRESSION NINE FORMS OVER THE EASTERN ATLANTIC...
...NO IMMEDIATE THREAT TO LAND...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.6N 34.9W
ABOUT 1755 MI...2820 KM E OF THE WINDWARD ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...STATIONARY
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Depression Nine was
located near latitude 13.6 North, longitude 34.9 West. The
depression is stationary and little motion is expected through
tonight. A westward motion with an increase in forward speed is
expected this weekend and early next week.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Little change in strength is expected during the next 24 hours, but
gradual strengthening is forecast late this weekend and early next
week.

The estimated minimum central pressure is 1007 mb (29.74 inches).



HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Cangialosi




Tropical Depression Nine Discussion Number 1
NWS National Hurricane Center Miami FL AL092018
500 PM AST Fri Sep 07 2018

Satellite images indicate that the low pressure system over the
eastern tropical Atlantic has developed a well-defined center and
sufficient deep convection to be classified a tropical depression,
the ninth one of the 2018 Atlantic hurricane season and second one
of the day. The initial intensity is set to 30 kt based on a 2.0
Dvorak classification from TAFB and earlier ASCAT data.

The depression has not moved much today, and it has even wobbled a
bit to the east recently. This slow motion is a result of very
weak steering with broad troughing to the north and Tropical
Depression Eight to its east. Little motion is expected through
tonight, but a westward motion with a gradual increase in forward
speed is forecast thereafter as a subtropical ridge builds to the
north of the cyclone. The NHC track forecast lies closest to the
HCCA guidance and takes the system toward the Lesser Antilles by the
end of the forecast period.

The depression is experiencing some influences of easterly shear,
which is why the center is currently on the eastern edge of the
convection. Little change in intensity is expected during the next
12 to 24 hours since the cyclone is still in the developing stage
and because moderate shear is expected to continue. However, the
shear is expected to decrease to less than 10 kt in about 24 hours.
These more favorable winds aloft combined with relatively warm
waters and a fairly moist airmass should allow for steady
strengthening beginning later in the weekend. There is a large
spread in the intensity guidance, with the HWRF showing the system
becoming a major hurricane and HMON showing almost no strengthening.
The NHC intensity forecast lies a little below consensus models
since it appears that it will take some time for the system to
strengthen.

FORECAST POSITIONS AND MAX WINDS

INIT 07/2100Z 13.6N 34.9W 30 KT 35 MPH
12H 08/0600Z 13.9N 35.2W 30 KT 35 MPH
24H 08/1800Z 14.0N 36.2W 30 KT 35 MPH
36H 09/0600Z 14.0N 37.6W 40 KT 45 MPH
48H 09/1800Z 14.0N 39.3W 50 KT 60 MPH
72H 10/1800Z 14.0N 44.0W 60 KT 70 MPH
96H 11/1800Z 14.1N 48.9W 70 KT 80 MPH
120H 12/1800Z 14.5N 54.5W 75 KT 85 MPH

$$
Forecaster Cangialosi

[cycloneye]

Will be a Hurricane on approach to Islands.

INIT 07/2100Z 13.6N 34.9W 30 KT 35 MPH
12H 08/0600Z 13.9N 35.2W 30 KT 35 MPH
24H 08/1800Z 14.0N 36.2W 30 KT 35 MPH
36H 09/0600Z 14.0N 37.6W 40 KT 45 MPH
48H 09/1800Z 14.0N 39.3W 50 KT 60 MPH
72H 10/1800Z 14.0N 44.0W 60 KT 70 MPH
96H 11/1800Z 14.1N 48.9W 70 KT 80 MPH
120H 12/1800Z 14.5N 54.5W 75 KT 85 MPH

[BobHarlem]

Hmm nine's advisories are mixed with Gordon's (at least on the NHC site)

[cycloneye]

[SoupBone]

Monday - Wednesday are going to be very key days to watch the steering for this system. Somewhere in those days, you'll likely see a settling pattern for the general path. It's not really looking great for the islands right now.

[cycloneye]

Go to Talking Tropics forum and vote in the poll about which TD gets the name first.

viewtopic.php?f=31&t=119882&p=2702400#p2702400

[SoupBone]

Why are people not talking about this more? I know Florence is the flavor of the hour, but this will start impacting the islands in around 5 days (if it's a larger system).

[northjaxpro]

Why are people not talking about this more? I know Florence is the flavor of the hour, but this will start impacting the islands in around 5 days (if it's a larger system).

I get what you are saying with the attention on Flo and rightfully so.. However, no question this system TD 9 looks to be a HUGE concern for our neighbors down into the Caribbean. Definitely the last thing the people need down there after last year's deadly season.

Definitely will be monitoring this closely as well as everyone else.

[SoupBone]

Why are people not talking about this more? I know Florence is the flavor of the hour, but this will start impacting the islands in around 5 days (if it's a larger system).

I get what you are saying with the attention on Flo and rightfully so.. However, no question this system TD 9 looks to be a HUGE concern for our neighbors down into the Caribbean. Definitely the last thing the people need down there after last year's deadly season.

Definitely will be monitoring this closely as well as everyone else.

Yeah, they will start feeling it's outer bands on Wednesday, if not sooner. And the fact that it's forecast to be a hurricane is very concerning for an area that still hasn't recovered yet from last year's nightmare.

[northjaxpro]

Yeah, very disheartening and ill feeling I have just thinking about this storm potentially impacting the Caribbean so soon after last year"s deadly rampage of storms down there. As you mentioned, many down there are not close to recovering at all from last year, if ever.

[EquusStorm]

Sure is, uh, interesting to see what will no doubt be the cursed 'I'-named storm with the forecast cone and its black H pointed right at Dominica

[SoupBone]

If it manages to take the track it's currently on, the GFS has been doing exceptionally well so far.

[AJC3]

Go to Talking Tropics forum and vote in the poll about which TD gets the name first.

viewtopic.php?f=31&t=119882&p=2702400#p2702400

Considering my thoughts that I'd be really surprised if this became a TD by 5...

[Florabamaman]

Why are people not talking about this more? I know Florence is the flavor of the hour, but this will start impacting the islands in around 5 days (if it's a larger system).

Just watched my local (Pensacola) met and his tropical discussion. He reported that 9 was still an invest with 90% chance of development. He has not realized that it has been upgraded to a TD. Pretty much skipped over it altogether and discussed TD 8 for a few seconds and said it was "way far out" and not a concern. If there is one storm to watch here in the panhandle its 9...

[cycloneye]

@EricBlake12
By the way, while #Florence is getting all the attention, Tropical Depression 9 formed this afternoon. Definitely one to watch in the Lesser Antilles for next week...

 https://twitter.com/EricBlake12/status/1038179064455020544