Possible development in the Western Atlantic / GOM (Is Invest 97L)

[DunedinDave]

Really the disagreement is where this thing will crank up.
Weak systems move further west. That’s why the GFS has this going into the gulf. It has it as basically just a wave til it hits the Gulf. Some of the other models like yesterdays Euro and the ICON wanted to crank it up around the Bahamas, and a strong system means a more likely north turn if the conditions are there.

[BobHarlem]

12z icon gets west of Grand Bahama, but stays east of Florida and goes out to sea, similar to 0z, but further right away from land.

[Emmett_Brown]

Many times, these late July waves never quite consolidate. (SAL, etc), but serve to start moistening the air for the waves that follow.

[toad strangler]

12z GFS doing the trip W through the N GOM again (albeit weaker) with a storm
12z CMC doesn't develop a TC but sends disorganized energy E of FL up towards Cape Hatteras

[chaser1]

A few random thoughts-

It's apparent that the broad mid-level tumbleweed low is slowly moistening up by simply seeing the increase in popcorn type cumulous buildups on vis satellite. This size system will sure need time for this to progress to any centralized convection, decent pressure falls, and organized banding features to develop.

I'm sure Michael Lowry didn't mean to sound as fence straddling as he did with ".... we expect a tropical depression or low-end tropical storm could form..." Meaning, I "expect" perhaps 5 different scenarios "could" occur .

Regardless of the watching glue dry evolution with this potential disturbance, I have to believe that at a minimum the NHC will want to get the Gulfstream out there before too long. The added upper air data over a large area will aid them in the difficult call for issuing PTC advisories. Last night's EURO 0Z run seemed to delay development of a 1010 mb low by 24 hr's (to occur around Sunday 12Z instead of it's prior 12Z run depicting closer to Sat 12Z time frame). Today's 12Z EURO run may push NHC to get that added Gulfstream data by Wednesday, or in contrast - have it's potential development cone nudged westward if today's GFS runs remain persistent on a GOM solution.

The EURO forecast seems to practically parallel TS Isaias from 2020 (albeit perhaps 1-2 degrees N of Isaias formation & track) and that system initially required NHC to declare TPC Advisories.

Interesting statistics from an 2022 NHC Webinar that reviewed 25 disturbances over a 3-year period (https://www.noaa.gov/sites/default/file ... 220517.pdf). Of 25 disturbances that NHC tagged as PTC's, only two did not ultimately develop into a T.S. That either speaks of some rather impressive forecasting by NHC, or an unwillingness to issue PTC advisories unless they are entirely confident that a TS will develop.

[WeatherBoy2000]

The 12z GFS run is similar in origin and track to the 06z but much weaker so far, not even a tropical storm.

[chaser1]

Many times, these late July waves never quite consolidate. (SAL, etc), but serve to start moistening the air for the waves that follow.

Yep, that's how I see this playing out. In fact, today's 12 GFS still showing some weak low in the NE GOM however distinctly weaker at 180 hr.s (1010mb as compared to 1003 & 1002 mb in it's previous runs). GFS is also a bit further east then it's prior runs so right now we have varying models closely straddling either side of Florida. Yesterday Wxman was thinking that NHC might soon push this disturbance to an increasingly higher percentage of likelihood. I'd probably back it off to about 40%.

[Spacecoast]

.
CMC / UK , & ICON (not shown) are the only models w/ genesis before 168hr (Aug 6th)..

[LarryWx]

12Z UKMET: similar to 0Z but weaker (TD vs TS) with trip from Key West vicinity into far E Gulf followed by turn into N FL; run ends with it near Jacksonville

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 108 HOURS
FORECAST POSITION AT T+108 : 25.0N 81.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 04.08.2024 108 25.0N 81.8W 1008 29
1200UTC 04.08.2024 120 26.8N 83.2W 1007 30
0000UTC 05.08.2024 132 28.0N 83.4W 1007 26
1200UTC 05.08.2024 144 29.2N 83.3W 1010 24
0000UTC 06.08.2024 156 30.2N 81.6W 1011 26
1200UTC 06.08.2024 168 30.0N 80.9W 1012 30

[LarryWx]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Tue Jul 30 2024

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

1. Near the Greater Antilles and the Bahamas:
A large tropical wave centered several hundred miles east of the
Lesser Antilles is producing limited shower activity due to
environmental dry air. Conditions are forecast to become a little
more conducive for development over the warmer waters of the
southwestern Atlantic Ocean, and a tropical depression could form
late this week while the system is in the vicinity of the Greater
Antilles or the Bahamas. Interests in the Greater Antilles, the
Bahamas, and the southeastern U.S. should monitor the progress of
this system.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...60 percent.


Forecaster Cangialosi

[WaveBreaking]

Starting to get some convection

[boca]

It seems like the cone is slowly shifting away from Florida with each update from the NHC.

[toad strangler]

It seems like the cone is slowly shifting away from Florida with each update from the NHC.

Yep. Apparently not putting much weight, if any, in the GFS

[LarryWx]

12Z Euro: forms at/near FL and turns NE/becomes a H; hits no land til Newfoundland.

[SouthFLTropics]

Just a couple of thoughts:

Watching this system try to come together is like waiting for a pot of water to boil. It seems like it may never happen, especially given the "current" appearance. However, this is exactly the type of system that you need to watch out for. One that has a decent circulation and manages to fly under the radar and wait to it gets close in to get its act together. Let's hope the current modeling is correct and this doesn't turn out to be more than what is currently shown. However, Beryl already showed us this season that the models still continue to struggle with TCG and more importantly the strength of systems. Despite its current look, if this circulation finds favorable conditions, it could pop in a hurry. I've always been fearful of a repeat of the 1935 Labor Day storm that devastated the Keys.

[BobHarlem]

12Z Euro: forms at/near FL and turns NE/becomes a H; hits no land til Newfoundland.

Struggling with a center too, check 96 vs 102 vs 108 hour, before forming over the Bahamas full out check 850 vorticity also), all on Saturday, Don't like these types of setups since they are prime for surprises. If you look at the GFS and it's almost splitting the low into two areas (look right of the main one one the GFS is in the gulf), this may be what the euro is tangling with here also.

[jlauderdal]

Just a couple of thoughts:

Watching this system try to come together is like waiting for a pot of water to boil. It seems like it may never happen, especially given the "current" appearance. However, this is exactly the type of system that you need to watch out for. One that has a decent circulation and manages to fly under the radar and wait to it gets close in to get its act together. Let's hope the current modeling is correct and this doesn't turn out to be more than what is currently shown. However, Beryl already showed us this season that the models still continue to struggle with TCG and more importantly the strength of systems. Despite its current look, if this circulation finds favorable conditions, it could pop in a hurry. I've always been fearful of a repeat of the 1935 Labor Day storm that devastated the Keys.

Development west of 60 spawms far more damaging hurricanes than the runners that tend to go fishing. This system a year ago wasnt making it past 70 with that setup, this year is very different. Bottom line, its not easy to make hurricanes.

[SFLcane]

It seems like the cone is slowly shifting away from Florida with each update from the NHC.

This is not a cone has never been rather covers were potential genesis might happen. For us on the eastcoast we might still get some impacts especially if its poorly organized which seems likely in the form of some loose rainbands. Just a teaser for ASO.

[toad strangler]

It seems like the cone is slowly shifting away from Florida with each update from the NHC.

This is not a cone has never been rather covers were potential genesis might happen. For us on the eastcoast we might still get some impacts especially if its poorly organized which seems likely in the form of some loose rainbands. Just a teaser for ASO.

Correct. Not an official NHC tropical cyclone cone. Most of us know that, but, it needs a name since we aren’t allowed to call it a cone without getting pulled over. How about Genesis Cone? Or GC lol. Whatever you want to call the shape, it still has relation to general track of an overall disturbance over a wide region.

[WaveBreaking]

Today's convection is starting to moisten the mid and upper-level ciruculations of the nothern vort max. Note how the darker shades W of the wave axis slowly begin to turn blueish-green near the end of the loop.


The southern vort max is still barren but is starting to get pulled N into the northern one, where it will eventually find better conditions in terms of moisture.