ATL: LEE - Post-Tropical Low - Discussion

[JBCycloneStan]

This is an odd scenario. It looks like sheared-off feeder bands of ex-Lee formed their own vortex north of the old Lee circulation. Does this make the new system Lee or Nate? Pretty fascinating stuff.

[tolakram]

Is now INVEST 98L

http://www.storm2k.org/phpbb2/viewtopic.php?f=59&t=119245&p=2647809#p2647809

[northjaxpro]

Looks like a completely closed circulation to me and in my opinion this is a tropical cyclone for sure. May be already Nate.

[OiOya]

I wonder if this is the same one that was spotted in this thread just yesterday?
If so, good eye.

[CyclonicFury]

UP TO 40/50 at 2:00 PM TWO
000
ABNT20 KNHC 221733
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Fri Sep 22 2017

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

The National Hurricane Center is issuing advisories on Post-Tropical
Cyclone Jose, located a little over a hundred miles south-southeast
of Nantucket, Massachusetts, and on Hurricane Maria, located just to
the north of Grand Turk Island.

A small area of low pressure, associated with the remnants of Lee,
is located over the central Atlantic Ocean almost a thousand miles
east-southeast of Bermuda. The low is producing a concentrated area
of showers and thunderstorms, although the circulation appears
somewhat elongated. Some additional development of this system is
possible during the next few days while it moves slowly northward
through early next week.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...50 percent.

$$
Forecaster Berg

[Vince_and_Grace_fan]

HWRF and HMON develops this into a small hurricane. It looks similar to Michael in 2012 which also developed from a small low and later became a hurricane.

[Michele B]

Could this system impact Maria at all?

Maybe push it westward more?

[CyclonicFury]

Interesting that the 2PM mentioned Lee in it. Maybe that means that if this regenerates, it will be Lee, not Nate?

[EquusStorm]

Uhhh... well, it's Lee again

Kinda seems like they're breaking precedence just a little with that but whatevs. Time to unlock and merge I guess?

Forecast intensity is just under hurricane in fairly favorable conditions... we are probably gonna keep the consecutive hurricane streak alive after all

---

Tropical Depression Lee Discussion Number 18
NWS National Hurricane Center Miami FL AL142017
500 PM AST Fri Sep 22 2017

The mid-level circulation from Lee separated from the low-level
center two days ago and moved northward around the eastern
periphery of a large upper-level trough. A large convective burst
over the mid-level center yesterday then caused a new low-level
center to develop while it moved on the northern side of the upper
trough. ASCAT and ship data indicate that the small circulation is
now well defined, and since deep convection has persisted near the
center, advisories on Lee are being restarted. The initial wind
speed is 30 kt, which could be conservative given the healthy
structure seen on the last-light visible and recent microwave data.

Cold upper-level temperatures from the upper trough should mitigate
the effect of marginally warm waters for the next few days while Lee
remains in a low-shear environment. The depression is expected to
strengthen over the next few days until westerly shear is forecast
to increase. The official forecast is similar to the model guidance,
although it shows an earlier peak more coincident with the
lower-shear, warmer-water environment. This wind speed forecast is
difficult because Lee is a very small tropical cyclone, which
notoriously have rapid changes, both up and down, in intensity.

Lee is moving northward at about 6 kt. The depression should turn
to the northeast and east over the next couple of days while it
moves around a ridge over the tropical central Atlantic. Lee is
forecast to become trapped beneath a mid-latitude ridge in a few
days, which should cause the cyclone to drift at long range. It
should be noted that models have a rather weak representation of
Lee at the present time, which causes this to be an uncertain
forecast. For now, the forecast is closest to the ECMWF, which
has the most coherent cyclone to follow.


FORECAST POSITIONS AND MAX WINDS

INIT 22/2100Z 30.8N 48.9W 30 KT 35 MPH
12H 23/0600Z 31.7N 48.7W 40 KT 45 MPH
24H 23/1800Z 32.3N 48.2W 45 KT 50 MPH
36H 24/0600Z 32.3N 47.2W 50 KT 60 MPH
48H 24/1800Z 32.1N 45.8W 55 KT 65 MPH
72H 25/1800Z 31.4N 43.2W 60 KT 70 MPH
96H 26/1800Z 30.5N 42.0W 55 KT 65 MPH
120H 27/1800Z 29.5N 43.0W 50 KT 60 MPH

$$
Forecaster Blake

[tolakram]

Oh now what do I do. I will merge this back into Lee and unlock. Good grief. Where is Luis when we need him, hopefully ok!

[tolakram]

Welcome back Lee.

[Hammy]

Uhhh... well, it's Lee again

Kinda seems like they're breaking precedence just a little with that but whatevs. Time to unlock and merge I guess?

Forecast intensity is just under hurricane in fairly favorable conditions... we are probably gonna keep the consecutive hurricane streak alive after all

There's precedent with doing this--I remember Dorian in 2013 and Bonnie in 2016 (as well as a few others I can't remember specifically) that were given different invest numbers prior to regeneration. I don't think it was don prior to 2013 though.

[galaxy401]

Quite odd that it's still Lee. Maybe that rule is more for basin crossers. Didn't Lee from 2005 do something similar as well?

[EquusStorm]

Uhhh... well, it's Lee again

Kinda seems like they're breaking precedence just a little with that but whatevs. Time to unlock and merge I guess?

Forecast intensity is just under hurricane in fairly favorable conditions... we are probably gonna keep the consecutive hurricane streak alive after all

There's precedent with doing this--I remember Dorian in 2013 and Bonnie in 2016 (as well as a few others I can't remember specifically) that were given different invest numbers prior to regeneration. I don't think it was don prior to 2013 though.

Ah, alright. Can't say that I knew that about those cases. I was out of town for Dorian's regeneration anyway, lol.

[WeatherGuesser]

BULLETIN
Tropical Depression Lee Advisory Number 18
NWS National Hurricane Center Miami FL AL142017
500 PM AST Fri Sep 22 2017

...LEE REGENERATES OVER THE CENTRAL ATLANTIC OCEAN...
...NO THREAT TO LAND...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...30.8N 48.9W
ABOUT 940 MI...1515 KM E OF BERMUDA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1014 MB...29.95 INCHES


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


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 500 PM AST (2100 UTC), the center of Tropical Depression Lee was
located near latitude 30.8 North, longitude 48.9 West. The
depression is moving toward the north near 7 mph (11 km/h), and a
gradual turn to the northeast and east is forecast over the next
couple of days.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours.

The estimated minimum central pressure is 1014 mb (29.95 inches).


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


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

$$
Forecaster Blake

------------------------------

I'm sooo ConFUSED!!!

[WeatherGuesser]

Has anybody seen a Bavarian Doc-Tor with a labor-a-tory around here?

[bg1]

The mid-level circulation from Lee separated from the low-level
center two days ago and moved northward around the eastern
periphery of a large upper-level trough. A large convective burst
over the mid-level center yesterday then caused a new low-level
center to develop while it moved on the northern side of the upper
trough.

Well then what if the old LLC regenerated as well? Lee-1 and Lee-2? I'm confused...

Edit: Have an idea for a hurricane season animation now...

[Kazmit]

Back from the dead, and now forecast take a strange track and become near hurricane strength. This season never ceases to surprise me.

[WeatherGuesser]

NHC is far too harried right now to entertain questions about this kind of thing, but maybe later one of the ProMets with their ear could ask about this?

[WeatherGuesser]

Season of the Zombies. How many have done this?

OK, back to this question. I know Harvey did, but wasn't there another?