Watching GOM for tropical development (Is INVEST 92L)

[cycloneye]

 https://twitter.com/DerekOrtt/status/1147918376024596481

[Aric Dunn]

UKMET again more detail. coming inline with Euro.

[cycloneye]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sun Jul 7 2019

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

A trough of low pressure over the southeastern United States is
forecast to move southward toward the northeastern Gulf of Mexico,
where a broad low pressure area will likely form in a few days.
Thereafter, upper-level winds support gradual development, and a
tropical depression could form late week while the low meanders near
the northeastern Gulf of Mexico coast through Friday. Interests
along the northern Gulf Coast and Florida peninsula should monitor
the progress of this system.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...50 percent.

$$
Forecaster Blake

[ColdMiser123]

Some pretty significant differences with the evolution of the trough to the north between UKMET runs, which allows for the potential disturbance to stay in the Gulf longer, hence a stronger, further west solution. Looking at the 588 dm 500 hPa contour, the trough at 0z on the UKMET had a larger north-south amplitude across the Southeast, which allowed the system to drift north sooner, and spend less time over the Gulf.



At 12z, the 588 dm contour over the Southeast was significantly further north, which allowed for more of a westward component before turning to the north at the end of the run. The trough closing off had a role with the limited meridional amplitude this run.



This trough originates from a poorly sampled region right now, so I wouldn't favor any particular solution at this time, just that everyone along the Gulf Coast should monitor the progression of this.

[northjaxpro]

Impressive vorticity signature over Northern Alabama/ NE MS currently on WV Imagery. It is moving south/southeast. This should reach the Apalachee Bay/Northeast GOM within the next 24 -30 hours. I have pretty good confidence that this will get trigger development into the Gulf. How far south it gets down into the GOM and the intensity and track are the big questions going forward.

[LeonardRay]

Impressive vorticity signature over Northern Alabama/ NE MS currently on WV Imagery. It is moving south/southeast. This should reach the Apalachee Bay/Northeast GOM within the next 24 -30 hours. I have pretty good confidence that this will get trigger development into the Gulf. How far south it gets down into the GOM and the intensity and track are the big questions going forth.

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/GIFS/GOES16-GM-08-1000x1000.gif

What effect would that upper low down in the sw gulf, bay of campeche have ?

[cycloneye]

Flooding is going to be the main hazard.

 https://twitter.com/DrRickKnabb/status/1147920419049103366

[chaser1]

Very clearly the mid to lower level vorticity is seen on satellite and 12z sounding, forecasted to track towards the NE GOM, A lot people are already looking at the NE GOM this morning but there is nothing but a surface trough at the moment.

https://i.imgur.com/AhBsRMi.gif
https://i.imgur.com/TtRY1Fm.gif
https://i.imgur.com/E3dYCED.gif

Without a doubt, it's very origin makes any evolution of this feature rather fascinating to watch! From a meteorology nerd perspective, I'd rather enjoy seeing this be forecasted in advance and then actually attain "legit" T.S. organization and intensity. Do I think it'll legitimately develop into a T.D.?? Nope. 'Course, that wont mean NHC won't tag it with a name LOL). As Jax previously mentioned above, more importantly is the potential flooding impact that this event could have on one or more regions (depending on how it all plays out). I tend to think Crownweather is right and what we'll see play out will likely be a compromise between what each of the EURO and GFS models are hedging toward; basically a (crapper) with too little time over water to warrant serious concern but probably a weather event that could cause serious flooding for a number of counties. I think the worse case risk would be to area's still recovering from Michael and especially those river regions that have been historically prone to cause overflow flooding.

Beyond that hey... "it's July" and I highly doubt there'll be anything else to potentially develop south of 25N for the foreseeable future, during a year which I still think will largely under-perform (in numbers and in ACE). So, why not geek-out on a potential tropical disturbance that originated near Kansas? At least there's a potential disturbance to watch less likely to be hampered by SAL or ENSO-like upper level shear

[cycloneye]

Great discussion twitter thread from Levi Cowan.

 https://twitter.com/TropicalTidbits/status/1147928654363734017




 https://twitter.com/TropicalTidbits/status/1147928664933392384




 https://twitter.com/TropicalTidbits/status/1147928667072466946

[northjaxpro]

Chaser1, we may possibly be looking at a situation like Debby 2012 up this way. It definitely is on the table for sure. We will know more in the details in the next 24-36 hours. But, most certainly, plenty of rain/potential flooding for some areas are possible as the week progresses.

[Aric Dunn]

Great discussion twitter thread from Levi Cowan.

https://twitter.com/TropicalTidbits/status/1147928654363734017

https://twitter.com/TropicalTidbits/status/1147928664933392384

https://twitter.com/TropicalTidbits/status/1147928667072466946

Yeah, thats about right.. and speaking of west short term motion to the vort.. the Euro is showing less of a hook and more a straight shot to the gulf. well over water in 72 hours..

[Aric Dunn]

Still diving sw at 96 hours.. going to texas this time ?

[storm4u]

At 96 hours the Euro seems like it's about to go beast mode.. way into the Gulf

[stormlover2013]

Still diving sw at 96 hours.. going to texas this time ?

No way Texas lol, saying New Orleans then will feel weakness then ne ne

[Aric Dunn]

Still diving sw at 96 hours.. going to texas this time ?

No way Texas lol, saying New Orleans then will feel weakness then ne ne

ridging is building in... and it had a lot of members into texas..

https://www.tropicaltidbits.com/analysi ... 0712&fh=96

[Steve]

UK met seems to only go as far west as 86.2 which is roughly on a parallel with Grayton Beach in Walton Co. That’s the 4th county east of the AL/FL border. So that’s a benchmark for the UK as of now.

[drezee]

12z throws a curve ball....not a good scenario

[Aric Dunn]

yeah, looks like its on a western LA eastern Texas track.. and deepening.

[TheProfessor]

quite the westward jump on the 12z Euro through hour 120.

[chaser1]

I would lean toward a right loaded QPF bomb with most of the rain dumping on florida. Most of these systems end up weak and right and that's what is probably most likely here. If it shakes out that way it will tame the extremely warm water temps in our part of the world which is usually what eventually happens when they get out of bounds.

Yep a right loaded QPF bomb looks likely. Latest GFS has that QPF swath (20+ inches of rain ) just offshore, any further east and the west coast of Florida from Tampa north would be in the bullseye. My guess is that this ends up further west than the GFS shows and more of a panhandle issue:

https://i.postimg.cc/ZnZZZ3CD/gfs-apcpn-seus-26.png

Agreed, what I've been kinda thinking as well. At least somewhat "right-loaded" and the heaviest precip training south to north into a somewhat narrow area. While I agree with Aric's point regarding lacking strong SW shear, I think all that mitigates is a broader fanned out precip impact to areas well east and northeast of any COC or trough axis. If this system were to remain weak and unable to coalesce over water, then some part of N. Florida may get drenched. What's worrisome is the increased model support for "stronger". That would likely translate to further south, more time over water, and a further west impact too.