ATL: LEE - Post-Tropical Low - Discussion

[Extratropical94]

Showers and thunderstorms continue near a low pressure area
associated with the remnants of Lee located about 1000 miles east of
the Leeward Islands. While this system is producing gale-force
winds, the associated thunderstorm activity has become less
concentrated during the past few hours. Although the enviromental
conditions are marginal, only a small increase in the overall
organization of the thunderstorms would result in the regeneration
of Lee. This low is expected to move northward over the central
Atlantic Ocean.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...70 percent.

[WeatherGuesser]

Season of the Zombies. How many have done this?

[CrazyC83]

DMax might bring this back over the top. Trying for a piece of the spotlight after being in dark shadows.

[WeatherGuesser]

Satellite data indicate that the remnants of Lee, located about
1000 miles east of the Leeward Islands, have become less organized
today and the associated winds have decreased below gale force.
Environmental conditions are currently not conducive for tropical
cyclone formation, but they could become a little less hostile in a
day or two. This low is expected to move northward over the central
Atlantic Ocean during the next few days.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...50 percent.


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


Lee hangin' in, but may be losing the fight for life.

[EquusStorm]

Looks like the remnant low has degenerated further in the last several hours, but I really hope it holds together and re-develops when conditions improve a little. Would be a fun and carefree open Atlantic storm to watch, unlike the significantly less fun and carefree island-obliterating monsters we've been having to the west.

[abajan]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed Sep 20 2017 ...

Shower and thunderstorm activity associated with the remnants
of Lee remain limited. Environmental conditions are expected
to remain unfavorable for significant development during the next
few days, and the chances of regeneration are decreasing. The low
is forecast to move north-northwestward or northward over open
waters of the central Atlantic Ocean.

* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...low...30 percent.

Forecaster Brown

[Vince_and_Grace_fan]

I don't know exactly which system is Ex-Lee from these, but the northern one looks quite good now.

[RL3AO]

Haven't looked any closer than that image, but it appears to be a tropical cyclone or at least very close to being one.

[tolakram]

 https://twitter.com/pppapin/status/911070809510301696




Philippe Papin @pppapin
Interesting feature w/ #Lee remains. Old sfc vortex dissipating, b/ new sfc vortex formed off mid-level center that sheared off yesterday.
11:33 PM - Sep 21, 2017 · Rotterdam, NY

[tolakram]

Updated: A small area of low pressure has developed 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...low...30 percent.
* Formation chance through 5 days...medium...40 percent.

$$
Forecaster Berg/Blake

[BYG Jacob]

Updated: A small area of low pressure has developed 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...low...30 percent.
* Formation chance through 5 days...medium...40 percent.

$$
Forecaster Berg/Blake

But.. it already looks like a TC...

[hcane27]

is this the ex-Lee ?? ... or a new one ??

AL, 98, 2017092200, , BEST, 0, 293N, 484W, 25, 1016, LO, 0, , 0, 0, 0, 0, 1018, 90, 25, 0, 0, , 0, , 0, 0, INVEST, ,
AL, 98, 2017092206, , BEST, 0, 296N, 487W, 25, 1016, LO, 0, , 0, 0, 0, 0, 1018, 90, 25, 0, 0, , 0, , 0, 0, INVEST, ,
AL, 98, 2017092212, , BEST, 0, 299N, 490W, 25, 1016, LO, 34, NEQ, 0, 0, 0, 0, 1019, 90, 25, 0, 0, L, 0, , 0, 0, INVEST, S,

[EquusStorm]

Might be pretty conservative with this one; it might develop way sooner than they think if organization persists. It also presents an interesting challenge; Lee's surface low is still out there dying to the south, as noted, so is a mid-level remnant good enough to re-use the name Lee or would this be Nate?

Being tagged 98L instead of Lee, I assume we'd have Nate...

[WeatherGuesser]

"Old sfc vortex dissipating, b/ new sfc vortex formed off mid-level center that sheared off yesterday."

So, would it be Lee or Nate?

[supercane4867]

The NHC has assigned this system as a new invest since the old surface center of Lee has dissipated. If this becomes a TS it will be named Nate.

Invest 98L
As of 12:00 UTC Sep 22, 2017:

Location: 29.9°N 49.0°W
Maximum Winds: 25 kt  Gusts: N/A
Minimum Central Pressure: 1016 mb
Environmental Pressure: 1019 mb
Radius of Circulation: 90 NM
Radius of Maximum Wind: 25 NM

[NotSparta]

"Old sfc vortex dissipating, b/ new sfc vortex formed off mid-level center that sheared off yesterday."

So, would it be Lee or Nate?

Nate. The new low is not associated with Lee's low level center, but the mid level one, meaning that if this forms, then it will be Nate. This happens usually when systems cross over into the EPAC and once with an infamous hurricane in 2005.

[EquusStorm]

Well there we have it, mystery solved. Hello, proto-Nate.

[BYG Jacob]

Well there we have it, mystery solved. Hello, proto-Nate.

Looks surprisingly good actually, might end up being a moderate TS before he moves too far north.

[EquusStorm]

Indeed. Usually I question if it wouldn't be one already, but looking over scatterometer data, it'd be iffy to say if it has a well defined surface spin just yet... however it's really really close.

[TheStormExpert]

So Ex-Lee would be Nate if it regenerates? I’m confused.