Watching GOM for tropical development (Is INVEST 92L)

[cycloneye]

I think is time to have a separated thread from the models one on what may happen to the area that the models ares showing with some development or not as they are not in consensus on that.

[cycloneye]

 https://twitter.com/DerekOrtt/status/1147540998412783616

[Aric Dunn]

ICON is on board with the EURO.

https://www.tropicaltidbits.com/analysi ... 70612&fh=9

[Nimbus]

Saw this in the long range forecast a few days ago. Tail ends of cold fronts over the warm gulf statistically develop into closed circulations maybe 5% to 10% of the time. Doubt they will be shutting down the oil rigs over this but worth watching.

[northjaxpro]

Yeah, just waiting for more model support to bolster EURO's solution. If the UKMET, in particular, joins in with the EURO, that would be significant for yours truly!

[TheAustinMan]

Yeah, just waiting for more model support to bolster EURO's solution. If the UKMET, in particular, joins in with the EURO, that would be significant for yours truly!

The 12Z UKMET tropical cyclone guidance output noted the development of a tropical cyclone in the northeastern Gulf of Mexico (28.4N, 85.5W, or 175 miles west of Tampa) in 138 hours (July 12). I'm waiting for the image outputs to see if the model is actually something at a well-organized feature, but it is a good sign seeing it on the initial text output statistics.

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 138 HOURS
FORECAST POSITION AT T+138 : 28.0N 85.4W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 12.07.2019 144 28.4N 85.5W 1003 40

[Aric Dunn]

Yeah, just waiting for more model support to bolster EURO's solution. If the UKMET, in particular, joins in with the EURO, that would be significant for yours truly!

00z UKMET has it but just keep it weak from shear. It is probably safe to say some sort of development is likely.

[cycloneye]

Here is the 12z ICON model showing development that Aric was mentioning.

[Shell Mound]

While the ECMWF/EPS, like the remainder of the global (dynamical) models, may or may not be handling future TCG (tropical-cyclone genesis) properly, it tends to do better at predicting the medium-range pattern than the GFS/GEFS, though the upgrades to the latter may close the performance-gap somewhat. One factor that may favour the ECMWF/EPS is the very warm SST anomaly over Baffin Bay and much of the Labrador Sea. This setup tends to promote mid-level ridging (bridging) over Greenland and adjacent portions of northern Canada, in the vicinity of Hudson Bay. In other words, the +SSTA promotes a feedback loop whereby a west-based -NAO is sustained. This induces lower heights (amplification) to the immediate south of the enhanced mid-level ridging. In turn, this would allow the mid-level trough to dig farther south over the Eastern Seaboard, enabling greater retrogression over the northern Gulf of Mexico. Therefore, if anything manages to develop, it will likely have more time over water than the GFS/GEFS suggest, and also be embedded in an environment of lower vertical wind shear, in line with the ECMWF/EPS solutions.

[northjaxpro]

Yeah, I think the odds for some type of development in the Northern GOM/NE GOM has increased. UKMET may get more bullish with time. We will see. It just depends just how far south this disturbance gets into Gulf. If it can get far enough south away from the coast and into better UL conditions, WATCH OUT! SSTs are around 90 degrees in areas in the vicinity of the Loop Current in the Gulf.

Also, - NAO would promote amplification of the trough as described in the post above by Shell Mound.

[Aric Dunn]

12z UKMET is a little stronger and more organized.

[northjaxpro]

12Z UKMET is also a little bit farther south into the Gulf this run as well.

[cycloneye]

Already the battle of the models is going on after the upgrades to the new FV3-GFS and ECMWF with the sidebars ICON,UKMET showing development.Let's see how things shape up in the models front to see which one pass the first true exam after those upgrades in the hurricane season.

[cycloneye]

Here we go.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sat Jul 6 2019

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

A trough of low pressure over western Kentucky, Tennessee and
northern Mississippi is forecast to move over the northeastern Gulf
of Mexico where a low pressure area could form early next week.
Some gradual development of the system is then possible as it drifts
westward over the northern Gulf of Mexico through midweek.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

$$
Forecaster Blake

[Aric Dunn]

you dont see that too often.. lol

[AnnularCane]

you dont see that too often.. lol

Point of origin somewhere around...Graceland?

[northjaxpro]

This certainly would be the true definition of a "home-grown " tropical cyclone should we get development in the next 5 days. You do not see origins of a potential system like this drift down from the Continental U.S. south into the GOM very often, or even into off the Southeast U.S. Atlantic coast for that matter.

[Aric Dunn]

It will be approaching the coast in 48 to 72 hours and its structure as it does will be key to how fast it develops.

[Nimbus]

20% sounds like they are already going with the low shear scenario?

[psyclone]

It's worth mentioning that even though OHC maps never depict good warmth over the NE Gulf owing to very shallow waters it is an absolute hot tub out there thanks to our southeast ridge. In my years here the waters are as persistently warm as I can recall. If a system forms heat potential won't be lacking. This same phenomenon was at work last September when our ridge roasted us in anomalous heat yielding exceptionally warm waters and Michael took advantage of those temps and gained strength right until landfall even as it passed over shallow shelf waters.