ATL: COLIN - Post-Tropical - Discussion

[AnnularCane]

I seem to recall another non-designated east coast low wreaking a fair amount of havoc, maybe a month or two ago? A bit of deja vu here. I don't know if it means anything or not, but these little lows are seeming rather intense.

[zhukm29]

Still improving... I wouldn't have thought this was a 20/20 disturbance to be honest, especially with TS wind reports coming out of SC...

An ASCAT pass from this morning showed a nascent circulation with winds at 30kt... I wouldn't be surprised if this was stronger now.

[MississippiWx]

Still improving... I wouldn't have thought this was a 20/20 disturbance to be honest, especially with TS wind reports coming out of SC...

An ASCAT pass from this morning showed a nascent circulation with winds at 30kt... I wouldn't be surprised if this was stronger now.

https://i.ibb.co/s6wrQRd/goes16-ir-96-L-202207020032.gif

Yeah, about time for the NHC to give this a lot more credit…

[tiger_deF]

Really impressive convective pattern with this one right now. Wouldn't be suprised if we've had a tiny TD/TS for the past several hours

[zhukm29]

Very strong vorticity signature, especially for an invest...

Really impressive convective pattern with this one right now. Wouldn't be suprised if we've had a tiny TD/TS for the past several hours

Yeah I definitely agree, I think reanalysis might put TCG a bit earlier, if it is ever designated at all. Maybe NHC is waiting for an ASCAT pass?

[zhukm29]

 https://twitter.com/WeatherFlowCHAS/status/1543073740254334976

[Teban54]

After Bonnie, it's refreshing to see a system developing so fast

This is giving me Bertha '20 vibes. If not operationally named, 96L will join 90L in my list of systems that might be classified as unnamed storms post-season.

[Landy]

STWO came out a few minutes ago bumping odds to 40/40.

1. Near the South Carolina Coast:
Updated: Recent surface observations indicate that a small low
pressure system located just inland to the west of Charleston,
South Carolina, is producing localized areas of winds to tropical
storm force along the South Carolina coast. This system is expected
to move northeastward along the South Carolina and North Carolina
coasts over the weekend, and a tropical depression or tropical storm
could form if the center of the low remains close enough to the
Atlantic waters during that time. Regardless of development, this
system is expected to produce heavy rains, which could cause flash
flooding across coastal portions of the Carolinas over the weekend.
See products issued by the Weather Prediction Center and your local
National Weather Service forecast office for more details.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...40 percent.

[zhukm29]

TS-force winds confirmed by ASCAT. The LLC seems to on the edge of the SC coast.

[MarioProtVI]

Looks like this thing really wants to be Colin…shame it can’t be used for a stronger storm to make up for the abysmal slop it was last time, but this time it’ll actually be a real TC!

[Hypercane_Kyle]

This should be tagged as a PTC, IMHO. Already producing TS-like impacts.

[Teban54]

This should be tagged as a PTC, IMHO. Already producing TS-like impacts.

IIRC, the PTC designation requires a high (70%?) chance of formation within the next 48 hours. The special TWO puts its chance at 40%, so not there yet.

Regardless, even if it doesn't become Colin during the next advisory cycle, I expect its formation chance to go up significantly to warrant PTC.

[zhukm29]

Looks like this thing really wants to be Colin…shame it can’t be used for a stronger storm to make up for the abysmal slop it was last time, but this time it’ll actually be a real TC!

Colin hasn't ever been used on a hurricane yet, but it'll only be its third use, so there's definitely time in the future. Maybe it will eventually get the Jose experience of being slop for multiple seasons and then becoming a powerhouse in 2017.

If anything, the last time Bonnie was a hurricane was in 1998... so this year's iteration of Bonnie might be its hurricane debut in the 21st century - and in the EPAC no less!

[NXStumpy_Robothing]

This should be tagged as a PTC, IMHO. Already producing TS-like impacts.

Personally, I would argue that this has been a TC for the past 12 hours given the continuous convective bursts near the center of a closed circulation that has been steadily increasing in strength and discerning itself from the surrounding environmental pressures. It clearly has satisfied the criteria for convective maintenance and surface-level organization of a warm-core low imo, so I don't see a reason to use the PTC designation over a TS one. Of course, the system could start failing to maintain the necessary feedback loop that separates TCs from tropical lows, but that doesn't seem likely as long as it remains just offshore.

If this goes unnamed, it will certainly be a system (like 90L in late May) that will merit a second look in post-season analysis.

Note: If the NHC goes 70/70 or higher at 2 am, then that would likely mean that they agree with this assessment and will begin issuing advisories on the system at 5 am. We'll see how they feel about it soon enough.

[CrazyC83]

The problem is that it is so close to the coast that tropical storm warnings would be needed immediately. If there is anything that resembles a tropical cyclone, then advisories should begin - give it the benefit of the doubt. This isn't out in the open ocean where you can watch and wait.

If it closes off, then a Special Advisory might be necessary without waiting for 5 am.

[CrazyC83]

Now up to 60/60.

1. Near the South Carolina Coast:
Surface observations and satellite-derived wind data indicate that
the small low pressure system located along the coast of South
Carolina is producing sustained tropical-storm-force winds
primarily to the southeast of its center over water and near the
immediate coast. In addition, shower and thunderstorm activity has
persisted near the area of low pressure over the last 6 to 12 hours.
If the associated showers and thunderstorms persist and continue to
become better organized, then this system could become a tropical
storm later today while moving northeastward along the South
Carolina coast, and then reaching the North Carolina coast by
tonight. Regardless of development, this system is expected to
produce heavy rains, which could cause flash flooding across coastal
portions of the Carolinas over the weekend. See products issued by
the Weather Prediction Center and your local National Weather
Service forecast office for more details. Further information on
the system, including offshore gale warnings, can be found in High
Seas forecasts issued by the National Weather Service.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.

[FireRat]

The problem is that it is so close to the coast that tropical storm warnings would be needed immediately. If there is anything that resembles a tropical cyclone, then advisories should begin - give it the benefit of the doubt. This isn't out in the open ocean where you can watch and wait.

If it closes off, then a Special Advisory might be necessary without waiting for 5 am.

I concur! Issuing a PTC for this one could retard the process, there will be coastal areas that will get TS effects real quick. Crazy to see how quick this thing came together and out of nowhere, and not too far from me to the southeast!

[ncforecaster89]

It has already met all of the standard requirements for TC designation and the confirmed TS sustained winds merit 96L’s immediate tropical storm classification.

I strongly suspect they’ve chosen to wait until the standard 5 am advisory interval, given it’s the overnight hours and provides them a little more time to see if the convection persists.

Again, one can justifiably argue it’s already TS Colin.

[Nancy Smar]

AL, 96, 2022070206, , BEST, 0, 330N, 798W, 35, 1012, TS, 34, NEQ, 40, 60, 0, 0, 1017, 110, 50, 45, 0, L, 0, , 0, 0, INVEST, S, 0, , 0, 0, 0, 0, genesis-num, 012,

[galaxy401]

Well this system came out of nowhere. Finally got Bonnie and Colin is now around the corner.