ATL: LEE - Post-Tropical Low - Discussion

[Dean_175]

NHC seems to be backing off the forecast of this developing at all into a tropical storm. Less and less tropical storm forecast points along the cone.

It seems that few systems that exist as a tropical depression for more than 24 hours actually reach storm status. I am starting to think that we may not get a name out of this, but we shall see.

[Hammy]

NHC seems to be backing off the forecast of this developing at all into a tropical storm. Less and less tropical storm forecast points along the cone.

It seems that few systems that exist as a tropical depression for more than 24 hours actually reach storm status. I am starting to think that we may not get a name out of this, but we shall see.

Two points vs three, but interestingly the forecast intensity is slightly higher than the previous advisory. I think this is probably a tropical storm already personally but we likely won't see an upgrade without an increase in organization or ASCAT pass.

[SuperMarioBros99thx]

NHC is surprising me.

[Dean_175]

Actually it may be looking a bit better on satellite. I would imagine a T2.5 for Dvorak. The convection is much more consolidated than it was yesterday. Can't access the link for ASCAT though as the website seems down.

[CrazyC83]

Seeing lots of barbs in the 30-35 range, and a few over 40 but contaminated.

[CrazyC83]

AL, 14, 2017091612, , BEST, 0, 125N, 328W, 35, 1007, TS, 34, NEQ, 60, 60, 0, 60, 1013, 150, 40, 0, 0, L, 0, , 0, 0, FOURTEEN, S, 0, , 0, 0, 0, 0, genesis-num, 029,

TS Lee at next advisory - likely at the last chance to grab the name as 97L may become Maria concurrently or shortly after.

[northjaxpro]

Tropical Storm Lee has been born 1007 mb. Upgrade coming at 11a.m.

[cycloneye]

Tropical Storm Lee Discussion Number 7
NWS National Hurricane Center Miami FL AL142017
1100 AM AST Sat Sep 16 2017

Deep convection has increased in intensity and coverage since this
time yesterday, and a recent partial ASCAT pass from around 1100
UTC indicated that the system is now producing tropical-storm-force
winds at least to the east of its center. Based on these data, the
depression is upgraded to Tropical Storm Lee with maximum winds of
35 kt. Lee has been able to strengthen a little despite about 15
kt of north-northwesterly shear. The cyclone appears to be located
in a sweet spot of relatively low shear, with much stronger upper-
level westerly winds located not too far to the north, and it may be
able to thread the needle of lower shear for another 36 hours or so.
After that time, the westerlies drop southward, and Lee will likely
be hammered by 30 kt of westerly shear by 48 hours. With all that
in mind, Lee is forecast to strengthen only slightly over the next
or so, with weakening expected to begin by day 3. The NHC intensity
forecast is close to the intensity consensus and HCCA, and Lee may
ultimately degenerate into a remnant low by day 5.

Lee's initial motion is estimated to be 265/10 kt. The storm is
located to the south of a weak mid-level ridge, and it is expected
to move generally westward or west-northwestward for the entire
forecast period. Although some of the track models are showing a
more pronounced poleward motion, Lee's relatively low intensity and
eventual weakening will likely keep it steered by lower-level flow.
As a result, the NHC track forecast is near the southern edge of
the guidance envelope, although not quite as far south as the ECMWF
model. This forecast is not too different from the previous one.

FORECAST POSITIONS AND MAX WINDS

INIT 16/1500Z 12.5N 33.1W 35 KT 40 MPH
12H 17/0000Z 12.4N 34.1W 40 KT 45 MPH
24H 17/1200Z 12.5N 35.3W 40 KT 45 MPH
36H 18/0000Z 12.9N 36.7W 40 KT 45 MPH
48H 18/1200Z 13.6N 38.4W 40 KT 45 MPH
72H 19/1200Z 15.6N 42.3W 35 KT 40 MPH
96H 20/1200Z 17.0N 46.0W 30 KT 35 MPH
120H 21/1200Z 18.0N 49.5W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg

[GlennOBX]

With Lee being one of 4 storms in the Atlantic in a relatively short time, would this cause the SSTs to drop significantly enough to inhibit intensification? Or is this not an issue?

[bob rulz]

It's not an issue. It would have to move over the exact same area as another storm within a few days for upwelling to have any effect.

[NotSparta]

Wonder if it'll be classified as a remnant low soon

[Buck]

convection trying to fire but not lasting long. Wonder how long this will exist as a naked swirl before dissipating?

[EquusStorm]

Probably going to be a remnant low quicker than forecast imo

[Hammy]

Interesting note, Lee is going to be the first storm since April not to have any land impacts.

[Bizzles]

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM

Tropical Depression Lee Discussion Number 14
NWS National Hurricane Center Miami FL AL142017
500 AM AST Mon Sep 18 2017

Lee's cloud pattern has deteriorated considerably this morning.
All that remains of the deep convection are a few fragmented bands
in the northeast quadrant. The initial intensity is generously
held at 30 kt for this advisory. Deep-layer shear is expected to
increase during the next 12 to 24 hours, and this inhibiting
factor should prevent the cyclone from maintaining what is left
of the deep convection. Consequently, Lee should degenerate into a
remnant low by tonight.

The initial motion is estimated to be west-northwestward or 290/11
kt. A west-northwestward to northwestward motion is expected
through the entire forecast period, or until the cyclone dissipates
in 3 days or earlier. No significant changes were made to the NHC
track from previous advisory and the official forecast is based
mainly on the HFIP Corrected Consensus technique.

FORECAST POSITIONS AND MAX WINDS

INIT 18/0900Z 14.1N 39.8W 30 KT 35 MPH
12H 18/1800Z 14.9N 41.2W 25 KT 30 MPH
24H 19/0600Z 16.0N 42.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 19/1800Z 17.1N 44.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 20/0600Z 18.5N 45.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 21/0600Z...DISSIPATED

$$
Forecaster Roberts

NNNN

[1900hurricane]

00Z best track downgrades Lee to a disturbance.

AL, 14, 2017091900, , BEST, 0, 148N, 427W, 25, 1007, DB, 34, NEQ, 0, 0, 0, 0, 1012, 120, 60, 0, 0, L, 0, , 0, 0, LEE, S, 0, , 0, 0, 0, 0, genesis-num, 029,

[1900hurricane]

Advisory text calls it a Remnant Low.

...LEE HAS DEGENERATED INTO A REMNANT LOW... ...THIS IS THE LAST ADVISORY...

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM

Remnants Of Lee Discussion Number 17
NWS National Hurricane Center Miami FL AL142017
1100 PM AST Mon Sep 18 2017

Lee has degenerated into a tight swirl of low clouds with
intermittent burst of convection, and no longer classifies as a
tropical cyclone. As forecast by global models, strong upper-level
westerly winds have become established over the disturbance, and
this pattern should not allow regeneration. Some additional bursts
of convection could still develop while the disturbance moves
northwestward until dissipation in a day or so.

This is the last advisory on Lee issued by the National Hurricane
Center.

FORECAST POSITIONS AND MAX WINDS

INIT 19/0300Z 15.1N 43.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
12H 19/1200Z 16.0N 44.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 20/0000Z...DISSIPATED

$$
Forecaster Avila

NNNN

[WeatherGuesser]

A small low pressure area, the remnants of Lee, is located roughly
midway between the Cabo Verde Islands and the Leeward Islands.
Environmental conditions could become marginally conducive for
redevelopment of a tropical cyclone by late in the week while the
system moves northwestward to northward over the central Atlantic
Ocean.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...20 percent.

[RL3AO]

Special TWO

1. Showers and thunderstorms have increased near a low pressure area,
the remnants of Lee, located about 1000 miles east of the Leeward
Islands. Satellite wind data show that the low is already producing
gale-force winds, and only a small increase in the organization of
the deep convection would result in the regeneration of Lee.
However, the environmental conditions are only marginal favorable
for tropical cyclone formation. 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...medium...60 percent.

[EquusStorm]

With the TWO at 60%, part of me kind of wishes Lee would regenerate over the open ocean and somehow find conditions to hit hurricane intensity briefly to keep the consecutive hurricane streak alive, heh... might as well go for more statistical points of note while we're at it.

Interestingly, it wouldn't be the first weak storm named Lee to have a discontinuous track to the east of (and after) a category five hurricane.