Tropical Wave in Bay of Campeche (Is Invest 91L)

[BIFF_THE_UNRULY]

I think 3-4 more days before we get a firm idea of thing thing. That’s when the models showing genesis start to show it.

Thats my play. If I dont see anything consistent by labor day, its a dud in my book

[Ubuntwo]

The wave has been steadily organizing following sunrise. Convection slid north/east like Teban mentioned earlier. It's a bit elongated, but the mid and low level centers are closer than they've ever been. I believe convective organization was not accurately captured on the 12z GFS - while the 12z Euro is pretty accurate.

[chaser1]

This IS season peak right now and some people on this board are expecting a trackable system and right now the basin should be ideal for development MJO or not.
This is sad to see areas of interest all strung out given the high expectations and the supposed peak right now.
Some areas of the Gulf coast need more rain and tropical systems are sometimes needed to fill basins etc. Does not always mean death and destruction from a T.S. or low end hurricane.

I slightly lean more toward MetroMike's perspective and i'll tell you why. Rightfully so, some of you point to trending ensemble forecasts, while others point toward climatology or perhaps NHC bumping up formation probability for the wave approaching the Lesser Antilles. One of the earliest lessons I learned about Meteorology was regarding "Persistence". Simply put, minus an absence of clear-cut data such as run to run model consistency and/or model corroboration, or some obvious satellite presentation showing signs of tropical genesis (or at least some increase and sustained convective consolidation) then often times the most reasonable near-term expectation is essentially more of the same. Naturally, that methodology of forecasting is crude, unspecific and has limitations. Right here and right now though, I'm looking at an Atlantic basin that is broadly suppressed and lacking well defined area's of disturbed weather other than a few whack-a-mole spots that might flare up due to diurnal forcing or divergent upper level wind shear. I was positive that a couple of named storms would develop during the first few days of September because... well.... Hyperactive season expectations, climo, anomalous SST's, yada yada yada. Well, something will eventually pop and that could be in 48 hr's or a week from now but for the moment I really do tend to consider Persistence as the best near-term guidance. Show me the money!

[IcyTundra]

Back down to 0/40 the NHC is going back in forth between 0/50 and 0/40 with this AOI.

[cycloneye]

Down to 40%.


Near the Lesser Antilles and Caribbean Sea:
A tropical wave located several hundred miles east of the Lesser
Antilles continues to produce some disorganized showers and
thunderstorms. The disturbance is forecast to move westward and
reach the Lesser Antilles on Monday, then continue across the
eastern and central Caribbean Sea through the middle part of next
week. Later next week, environmental conditions appear to become
more conducive for development, and a tropical depression could
form as the system moves across the western Caribbean Sea.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...40 percent.

[chaser1]

The wave has been steadily organizing following sunrise. Convection slid north/east like Teban mentioned earlier. It's a bit elongated, but the mid and low level centers are closer than they've ever been. I believe convective organization was not accurately captured on the 12z GFS - while the 12z Euro is pretty accurate.

FWIW, NHC lowered the 8:00am 0/50% to 0/40% at 2:00pm. I'll be the first to say that this does not mean all too much but the point is that this conveys less confidence of near to mid term improvement of conditions. And onward we go

[Spacecoast]

I know EPS false alarmed a system earlier this season, but it seems to have caught the storms that have developed earlier than the GEFS. This may be a big nothingburger, but writing it off because the GFS and its ensembles aren't super enthusiastic (although about a third are pretty enthusiastic) when the EPS are enthusiastic may be a mistake. I'm counting 6 of 31 GEFS members with significant lows in the Gulf, and a couple of more with weaker systems at Day 10. Not even the GFS ensembles are signaling Gulf cancel.

As far as ensembles go, the EPS have a high percentage of members developing this AOI. Importantly, it still shows ~20% chance of a Hurricane striking anywhere from TX to Fl panhandle (see EPS 0z strike prob). The EPS track spread is still very wide, so any specific track is up in the air. Given the possibility of intensification in the Gulf, it would be prudent to prepare for any impacts, should such a scenario materialize.

It's important to evaluate all 31 GEFS members as equally valid possible outcomes. While it is true that 6 of 31 have significant lows in the Gulf, it is equally true that
~17 members do not develop this at all.

I personally don't see either extreme predictions like 'Gulf cancel', or Andrew / Alicia analogies as likely outcomes, but I have no crystal ball.
Perhaps a track between Beryl, and Debbie is the best guess ATM.

[aspen]

Huge downtick in the operational 12z models today. Euro throws the wave right into The Shredder before it can ever established a concentrated vort.

[Ubuntwo]

The wave has been steadily organizing following sunrise. Convection slid north/east like Teban mentioned earlier. It's a bit elongated, but the mid and low level centers are closer than they've ever been. I believe convective organization was not accurately captured on the 12z GFS - while the 12z Euro is pretty accurate.

FWIW, NHC lowered the 8:00am 0/50% to 0/40% at 2:00pm. I'll be the first to say that this does not mean all too much but the point is that this conveys less confidence of near to mid term improvement of conditions. And onward we go

Yeah, the ensembles no longer really supported 50% and many operational runs have either no development or delay it beyond day 7. The organization was expected, and it's a little behind schedule, but I figure it was still worth a mention & we will see what happens.

[Stratton23]

And the EPS largely disagrees with the operational run, chsnces for development should have just stayed at 50%, i really dont see any reason for the NHC to keep flip flopping chances unless support really drops off, and it hasnt

[Ubuntwo]

Huge downtick in the operational 12z models today. Euro throws the wave right into The Shredder before it can ever established a concentrated vort.

This is not true. While the 12z Euro has slower/weaker development, it does not crash into Hispaniola. The model spins up a 1006mb TC immediately before landfall in Belize. Ridging is so strong it never gets into the Gulf, though.

[Stratton23]

The EPS still has numerous members showing a powerful system affecting the gulf coast, we got a long ways to go with this one folks, Mexico- florida is in play for something, or also just a weak system

[Ubuntwo]

The EPS still has numerous members showing a powerful system affecting the gulf coast, we got a long ways to go with this one folks, Mexico- florida is in play for something, or also just a weak system

Yes, although we are down to ~37% developing by hour 144 vs. 50% on the 6z and 59% on the 0z.

[SouthFLTropics]

One thing I've learned over my entire life of living in Florida, regardless of what models show, is don't turn your back on a mass of convection moving west through the MDR in August and September. Models are just a tool in the toolbox. Just when we think we've got it figured out, we don't. I think monitoring the evolution of the convection over the next few days will be more important than long range model watching at this point in time. Pay attention to real time and keep at least one eye on it.

[cycloneye]

Huge downtick in the operational 12z models today. Euro throws the wave right into The Shredder before it can ever established a concentrated vort.

Even a piece goes to EPAC.

[gatorcane]

12Z Euro going with a crossover to the EPAC with development. Quite the change from the 00Z run and some prior runs with the sharp north turn into the Gulf.

[cycloneye]

Beings more weak and moves fast, it avoids the trough to the NW and in this 12z Euro run, ends in EPAC.

[Stratton23]

The one thing i noticed about that euro run is despite having ridging sending this wave into CA, it still has a frontal boundary in the gulf of mexico, it wouldn’t take much for a system to get tugged to the north if you have a front sitting in the gulf like that, this 500mb height pattern is extremely sensitive

[jlauderdal]

Wxman57 will get a few weeks off the way its setting up.

[Teban54]

The posts in this forum are NOT official forecasts and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the NHC and NWS.

Let's take a break from model runs and look at how the system is evolving in real time, shall we?

Over the past few hours, especially the past hour, there seems to be substantial improvement in the wave's organization on satellite imagery. In my unprofessional opinion, near the end of the loop below, you can see the system actually becoming a coherent entity with a reasonably well-defined center, instead of a few vorts side by side with linear convection.



This trend seems to be corroborated with vorticity analysis as well. The secondary vort at 500 mb that had been in place for much of the past 24 hours seems to be either dissipating or merging with the main one (which has stacked with lower levels).



Given the organization trends, I personally find it hard to believe the models (especially 12z runs) that make the wave strung out immediately after. But that could be just me.