Tropical Wave over the SE Bahamas (Is INVEST 91L)

[Dylan]

 https://twitter.com/dylanfedericowx/status/1034786966351560704

[SoupBone]

Can someone post the criteria for being declared in invest? I'm not questioning the fact that it hasn't been declared an invest yet, but I'm curious about the criteria and if it's close.

[Blown Away]

ECMWF develops the Low a bit farther E in the Bahamas compared to previous runs. I suspect if the low had more time over the GOM it would develop more like we saw in previous runs.

[NotSparta]

Beginning to show similar setups like it did for Rita and Katrina, before the waves made it to the gulf the models had them hitting Florida and possibly re-curving but continued to push through and hit Texas and Louisiana. History likes to repeat itself. well see

Dude, you’ve been constantly trying to compare this wave to Katrina or Rita. Something like those storms COULD happen but chances are slim to none at the moment.

The way the euro steers it doesn't give this much time to become strong, no matter if there are favorable conditions or not. I think a reasonable call if this forms is a TD/weak TS

[stormlover2013]

No it’s where the euro has it forming not steering it

[Bocadude85]

If you blend the GFS and Euro you get a robust tropical wave moving through Florida into the gulf.

[wxman57]

Can someone post the criteria for being declared in invest? I'm not questioning the fact that it hasn't been declared an invest yet, but I'm curious about the criteria and if it's close.

There are no rigid criteria for declaring an invest. An invest is declared when the NHC would like to start running model data on something of interest in the tropics. There is no requirement for a specific chance of development, or any chance of development at all. Thus, the declaration of an invest does not mean development chances are increasing, or are even good at all. There's really little value in the declaration, as the models that are run do not perform well out of the very deep tropics (south of 18N or so) where high pressure to the north will keep a disturbance moving westward. In such cases, they can provide an idea of possible timing of arrival of a system that moved off the coast of Africa, say, reaching the eastern Caribbean.

That said, I think the most likely scenario with this wave is that increased rain chances for south Florida over the weekend and across the central to NE Gulf Coast next week.

[SoupBone]

Can someone post the criteria for being declared in invest? I'm not questioning the fact that it hasn't been declared an invest yet, but I'm curious about the criteria and if it's close.

The official definition of invest for those playing along at home:

"Invest:
A weather system for which a tropical cyclone forecast center (NHC, CPHC, or JTWC) is interested in collecting specialized data sets (e.g., microwave imagery) and/or running model guidance. Once a system has been designated as an invest, data collection and processing is initiated on a number of government and academic web sites, including the Naval Research Laboratory (NRL) and the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies (UW-CIMSS). The designation of a system as an invest does not correspond to any particular likelihood of development of the system into a tropical cyclone; operational products such as the Tropical Weather Outlook or the JTWC/TCFA should be consulted for this purpose."

So no specific criteria it looks like, and even if it's declared, it's not because they think it will become anything. Interesting. Honestly, I think I have to refresh my memory each season wit this term for some reason. I'm a criteria/threshold type of person, so I always ask this question every season.

[SoupBone]

Can someone post the criteria for being declared in invest? I'm not questioning the fact that it hasn't been declared an invest yet, but I'm curious about the criteria and if it's close.

There are no rigid criteria for declaring an invest. An invest is declared when the NHC would like to start running model data on something of interest in the tropics. There is no requirement for a specific chance of development, or any chance of development at all. Thus, the declaration of an invest does not mean development chances are increasing, or are even good at all. There's really little value in the declaration, as the models that are run do not perform well out of the very deep tropics (south of 18N or so) where high pressure to the north will keep a disturbance moving westward. In such cases, they can provide an idea of possible timing of arrival of a system that moved off the coast of Africa, say, reaching the eastern Caribbean.

That said, I think the most likely scenario with this wave is that increased rain chances for south Florida over the weekend and across the central to NE Gulf Coast next week.

Haha, look one post down. I went and found it. Appreciate your response too. I think I do this every season.

[gatorcane]

850MB vorticity increasing over the Northern Leewards:

[slamdaddy]

This may become this biggest thread in storm2k history ? 388 entries and not even and invest yet.

[otowntiger]

192 hours, the Euro makes it a Panhandle problem.

But not much of one, lol. A weak TS or TD it looks there.

Be careful to downplay a weak TS as “not much” of a problem. Allison was a weak TS and one of the costliest storms in history, and her name was retired.

Most deaths from tropical cyclones are the result of inland flooding.

ok, thanks.

[stormlover2013]

Beginning to show similar setups like it did for Rita and Katrina, before the waves made it to the gulf the models had them hitting Florida and possibly re-curving but continued to push through and hit Texas and Louisiana. History likes to repeat itself. well see

Dude, you’ve been constantly trying to compare this wave to Katrina or Rita. Something like those storms COULD happen but chances are slim to none at the moment.


From levin cowan: A tropical wave east of the Leewards will be warily monitored as it comes west.

Its interaction w/ the PV streamer is key. Such interactions can organize convection & lead to genesis (e.g. Rita '05), but can also shear the wave. EC has a weaker PV streamer and/or more convection

[jlauderdal]

This may become this biggest thread in storm2k history ? 388 entries and not even and invest yet.

that's what happens when its been dead and we are at the end of august and you have Floridians and Texans in the game

[Blown Away]

Vorticity on latest ECMWF. I would think this area will get a yellow tag soon...

[psyclone]

A tropical system is the best way to disperse the red tide that has been plaguing southwest florida for 9 months. My -removed- here is aggressive.. Let's give the pot a big stir

[otowntiger]

Vorticity on latest ECMWF. I would think this area will get a yellow tag soon...

sorry, off topic, but i couldn't help but notice that the 'train' of the CV sytems forming, the first two look to recurve well out to sea, at least according to this model. Activity picking up for sure, but maybe the ridge stays back enough at least for the near term to keep systems originating there away from land.

[gatorcane]

Shear dropping over Bahamas and east of Florida:

[Hypercane_Kyle]

I do worry about this one. Has the look of a classic homebrew storm. I know the Euro only shows a TS in the GOMEX, but previous runs have shown a hurricane. Land interaction/time over the GOMEX appears to be the limiting factor here.

[Bocadude85]

12Z GFS is about to start, we shall see if it starts to come around to the Euros solution.