ATL: INVEST 92L - Discussion

[northjaxpro]

I think the reason why the GFS and the Euro do not develop much if any, 92L, is because is going to be getting squeezed between the Southern US heat ridge and the ULL, and it may very well get sheared away by UL NE winds by at least Friday.

Yeah, a very good observation NDG. You can see the squeeze play very well right now on water vapor imagery, with the northerly to northeastly upper wind flow beginning to come into extreme Northeast Florida from the Southern U.S. ridge you identified, and the ULL off to the east.

92L just may feel those upper level northerly and northeaterly winds within the next 36 hours or so and get sheared. We will find out.

[tolakram]

Latest. New convection firing as the sun sets.

[tolakram]

Live IR loop

http://wwwghcc.msfc.nasa.gov/cgi-bin/get-goes?satellite=GOES-E%20CONUS&lat=27&lon=-77&info=ir&zoom=1&width=1200&height=720&quality=95&type=Animation&palette=ir3.pal&numframes=10

RAMSDIS floater: http://rammb.cira.colostate.edu/ramsdis/online/loop.asp?data_folder=tropical/tropical_ge_4km_visir2_floater_1&width=640&height=480&number_of_images_to_display=12

[perk]

Was working on a study since 7am today, so just looked at this disturbance around 3:45pm. In my opinion, there is evidence that a low-level circulation center has developed. It's not strong, but I think it's present. Convection remains weak and disorganized, located generally NW of the weak LLC. I see a large outflow boundary moving outward in the western half of the disturbance, a sign of collapsing squalls.

Both the EC and GFS carry the vorticity south of west across Florida and the Gulf, reaching NE Mexico to south Texas next Monday afternoon (GFS) or Tuesday (EC). Neither indicates any significant development (just a wave after passing Florida). A 20-30% chance of development looks good for now, but I am concerned that it already does appear to have a LLC. It should move over Florida on Friday morning, so we'll see if that LLC can persist. Conditions in the Gulf don't look TOO hostile toward development, but there's the issue with the cold front reaching the NW Gulf on Saturday.

Both the GFS and Euro indicate that the front will stall along the TX coast on Saturday. Will it? If it doesn't stall, then the disturbance may not continue its westward trek. What about dry air moving out over the Gulf being ingested by the disturbance by late Sunday? That could certainly be an inhibiting factor.

Something to keep a close eye on for the next 4-5 days. It doesn't look like a hurricane threat - for now.

Any chance 92L can get to the NW GOM.

[wxman57]

Any chance 92L can get to the NW GOM.

I wouldn't say there is NO chance, but the frontal boundary should be located from the mid TX coast to the SW LA coast by the weekend. It probably wouldn't head right for the front. It would either continue W-WSW toward NE Mexico or south TX or take a turn northward toward the mid to NE Gulf coast ahead of the front.

[SeGaBob]

If I had to guess I think NHC will raise development chances to at least 40/50% at 8pm. Whether they do or not it does appear more organized than it did at 2pm.

[MGC]

With the formation of a surface circulation today, odds apear to be increasing this afternoon for 92L to become a TC. Looking at the WV loop, there is a anti-cyclone over the disturbance, shear is minimal....SST are plenty warm...but, there appears to be some dry air over the central Bahama's that could hinder rapid development. Looks to be a well established east to west low level flow into the central GOM. Convections appears to be waning currently. With a forecast track into the GOM, I'm going to pay particular attention to this disturbance. Gotta have good weather on Saturday afternoon as we are hosting a pool party for my great-granddaugher's fourth birthay!....MGC

The above is the opinion of MGC and not an official forecast.

[wxman57]

Very good video discussion on 92L (and 91L). He explains why 92L may have a tough time developing beyond 24-48 hrs:

http://www.tropicaltidbits.com/blog/2014/09/10/92l-to-bring-rain-to-florida-91l-may-develop-well-out-to-sea/

[northjaxpro]

Yep, NDG pointed out those strong upper level northeasterly winds from the Southern U.S. ridge earlier on this page. If those winds reach 92L , I don't see development in the short term after about 36 hours.

[TARHEELPROGRAMMER]

It looks like it is dieing to me as we speak does anyone feel the same?

[Brent]

A weak area of low pressure has formed near the northwestern
Bahamas, and its associated shower activity is showing some signs of
organization. However, the environment is forecast to become
unfavorable for significant development while the low moves slowly
westward toward southern Florida. If necessary, an Air Force plane
will investigate this system tomorrow. Regardless of development,
this low will bring heavy rains over portions of southern Florida
and the Florida Keys during the next couple of days.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...30 percent.

[tropicwatch]

Pressures have been gradually falling on Great Abaco. Down to about 1013.5mb

[SFLcane]

Bla...this season is getting old.

[Blown Away]

A weak area of low pressure has formed near the northwestern
Bahamas, and its associated shower activity is showing some signs of
organization. However, the environment is forecast to become
unfavorable for significant development while the low moves slowly
westward toward southern Florida. If necessary, an Air Force plane
will investigate this system tomorrow. Regardless of development,
this low will bring heavy rains over portions of southern Florida
and the Florida Keys during the next couple of days.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...30 percent.

Yellow to Orange...

[jlauderdal]

A weak area of low pressure has formed near the northwestern
Bahamas, and its associated shower activity is showing some signs of
organization. However, the environment is forecast to become
unfavorable for significant development while the low moves slowly
westward toward southern Florida. If necessary, an Air Force plane
will investigate this system tomorrow. Regardless of development,
this low will bring heavy rains over portions of southern Florida
and the Florida Keys during the next couple of days.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...30 percent.

nhc is very good inside 72 hours..highly unlikely they miss the uprights..not much here to get excited about other then its close to our shores

[TARHEELPROGRAMMER]

Multiple eye walls forming lol. That could also be it being tore apart. Enjoy the nice weather Florida.
https://imageshack.com/i/idzqOEGhp

[Hammy]

nhc is very good inside 72 hours..highly unlikely they miss the uprights..not much here to get excited about other then its close to our shores

I will say one thing, when it comes to smaller systems like this, even the tiniest change in atmospheric conditions can make or break a system, and if there's even a tiny window of opportunity in an otherwise unfavorable environment, you can get a good amount of intensification in a short time, Bertha this year being a good example of this.

[tropicwatch]

Convection is building again. Question is will it continue overnight.

[jlauderdal]

nhc is very good inside 72 hours..highly unlikely they miss the uprights..not much here to get excited about other then its close to our shores

I will say one thing, when it comes to smaller systems like this, even the tiniest change in atmospheric conditions can make or break a system, and if there's even a tiny window of opportunity in an otherwise unfavorable environment, you can get a good amount of intensification in a short time, Bertha this year being a good example of this.

yep, small system like bertha or charly would be the type to surprise..lets see if it can maintain some convection

[LarryWx]

Looking at infrared satellite photos this evening, I see renewed healthy convection as older dies out. I'm now thinking 2/3 chance of a TD+ while still E of FL due to current conditions being so favorable (well organized with small size/good moisture/high SST's/upper high/light shear/far enough from land since Bahamas don't interfere much). Anyone disagree with this high of a chance E of FL?

Edit: Another way to put this: how much more favorable a combo of factors can there be? Are the overall factors as favorable as they seem to me?