2020 Global Model Runs Discussion (Out thru day 16)

[toad strangler]

What in the world went on during the past 24 hrs about a deep trough in the GFS's 10+ day range,
You should know better than that.

 http://twitter.com/BenNollWeather/status/1299697057293271040

[Ivanhater]

I don't think some of these posts are going to age well as we head into September and I know some of y'all have been here long enough to know better. Smh.

[SFLcane]

If the West Atlantic ridge holds to some extent, you could see a storm moving S->N along the East Coast.

[SFLcane]

What in the world went on during the past 24 hrs about a deep trough in the GFS's 10+ day range,
You should know better than that.

http://twitter.com/BenNollWeather/status/1299697057293271040?s=20

That would certainly be a problem if it came to pass.

[NDG]

What in the world went on during the past 24 hrs about a deep trough in the GFS's 10+ day range,
You should know better than that.
Here's the GFS a few days ago showing a deep trough in the NE US early next week in its 10 day range.
https://i.imgur.com/70O4tWr.png

Here's the short range GFS, where's the trough?
https://i.imgur.com/zezFGrI.png

Plus something else to think about, even if a deep trough comes down the GLs/NE US into the MS river valley like the last one did a few days ago, if they do not keep progressing eastward the strong Atlantic/Bermuda ridge will still be taking hold just off of the US coast keeping the threat to at least the eastern US from tropical systems.

https://i.imgur.com/XJsbJ9f.gif

We shall see... Just gotta keep an eye on it.

With the recurving typhoons, you get a ridge->trough->ridge->trough pattern. Like Isaias/Irene/Floyd

Which all 3 of them made landfall in the eastern US.
I just don't see a OTS pattern setting up like in 2010 & 2011 as some are trying to indicate.

[SFLcane]

What in the world went on during the past 24 hrs about a deep trough in the GFS's 10+ day range,
You should know better than that.
Here's the GFS a few days ago showing a deep trough in the NE US early next week in its 10 day range.
https://i.imgur.com/70O4tWr.png

Here's the short range GFS, where's the trough?
https://i.imgur.com/zezFGrI.png

Plus something else to think about, even if a deep trough comes down the GLs/NE US into the MS river valley like the last one did a few days ago, if they do not keep progressing eastward the strong Atlantic/Bermuda ridge will still be taking hold just off of the US coast keeping the threat to at least the eastern US from tropical systems.

https://i.imgur.com/XJsbJ9f.gif

We shall see... Just gotta keep an eye on it.

With the recurving typhoons, you get a ridge->trough->ridge->trough pattern. Like Isaias/Irene/Floyd

Which all 3 of them made landfall in the eastern US.
I just don't see a OTS pattern setting up like in 2010 & 2011 as some are trying to indicate.

It’s tricky.. just gotta wait and see if something is there to take advantage. Hopefully not

[Shell Mound]

What in the world went on during the past 24 hrs about a deep trough in the GFS's 10+ day range,
You should know better than that.

http://twitter.com/BenNollWeather/status/1299697057293271040?s=20

Note that the GFS Parallel has also been consistently far more reliable than the GFS itself thus far in 2020. Besides the upcoming synoptic pattern, I would also argue that the “clustering” of tracks strongly supports potential TC threats to the Carolinas, Mid-Atlantic, and/or New England sometime in mid-September. For example, besides the numerous impacts in TX and LA (northwestern Gulf Coast), principally Cristobal, Hanna, Laura, and Marco, we have already seen three or more TS+ impacts from SC to NY, including Bertha, Fay, and Isaias. A strong, negatively tilted trough centred over the Great Lakes with equally strong blocking just off the Eastern Seaboard—namely, centred near the Canadian Maritimes—would definitely support the notion of additional threats to the aforementioned region(s). The western Gulf and the Carolinas/Mid-Atlantic/New England definitely seem to be the preferred “hotspots” for U.S. impacts in 2020.

[NDG]

What in the world went on during the past 24 hrs about a deep trough in the GFS's 10+ day range,
You should know better than that.

http://twitter.com/BenNollWeather/status/1299697057293271040?s=20

Note that the GFS Parallel has also been consistently far more reliable than the GFS itself thus far in 2020. Besides the upcoming synoptic pattern, I would also argue that the “clustering” of tracks strongly supports potential TC threats to the Carolinas, Mid-Atlantic, and/or New England sometime in mid-September. For example, besides the numerous impacts in TX and LA (northwestern Gulf Coast), principally Cristobal, Hanna, Laura, and Marco, we have already seen three or more TS+ impacts from SC to NY, including Bertha, Fay, and Isaias. A strong, negatively tilted trough centred over the Great Lakes with equally strong blocking just off the Eastern Seaboard—namely, centred near the Canadian Maritimes—would definitely support the notion of additional threats to the aforementioned region(s). The western Gulf and the Carolinas/Mid-Atlantic/New England definitely seem to be the preferred “hotspots” for U.S. impacts in 2020.

I agree, the troughs that have come have been negatively positioned still giving the US a threat because ridging across the Atlantic has stayed present more often than not.
So just because a strong trough may come down the US in about 10 days it does not mean many if any OTS tracks setting up. The only ones that I may see going OTS are the ones that may develop strong sooner just off of the CV Islands, eventually once the SAL outbreaks settle down and they track through a break in the ridge in the middle or eastern Atlantic.

[SFLcane]

Who added the magnet in the eastern Atl?

[TheStormExpert]

I’m basically disregarding all the global models at this point. As we’ve seen numerous times this season they are useless for TCG. So basically that leaves me no choice but to nowcast.

[TheStormExpert]

If the West Atlantic ridge holds to some extent, you could see a storm moving S->N along the East Coast.

With semi-permanent ridging basically placed over SE Canada and the NW Atlantic that would reinforce the idea of a mid-Atlantic or NE U.S. threat. Maybe Fay was a precursor of what’s to come?

[gatorcane]

The GFS is back to showing quite a trough for the Eastern CONUS. Taste of fall:

[TheStormExpert]

I was never sold yesterday on any long-range OTS solutions until I saw Michael Ventrice’s Tweets. But these model solutions are 10+ days out are more than likely to change.

[gatorcane]

12Z GFS animation of eastern CONUS trough in the medium to long-range. I doubt it will be as deep as it shows but you can see how it is modeling it and how it evolves. The model has a couple of weak recurving Cape Verde lows:

[SFLcane]

All signals for genesis are stuck in the D10+ range.

[SFLcane]

Something is just off about this season.

[toad strangler]

Something is just off about this season.

Yeah, on modeling.

[TheStormExpert]

Something is just off about this season.

In the MDR yes, but we just had a 150mph Cat.4 slam into SW Louisiana a few days ago. 2005 didn’t really produce much of anything in the Tropical Atlantic and look how it turned out! This is definitely no 2005 repeat in terms of ACE but number of storms-wise it may be.

[bohai]

Not sure if this is where to post this but it may have an affect on future models. 45 people have drowned in SW Niger, near the city of Niamey where the Niger River has overflowed due to excessive rains. This is slightly north of the African tropical belt but may be getting influenced by these heavy rains.

[chaser1]

http://twitter.com/BenNollWeather/status/1299697057293271040?s=20

Note that the GFS Parallel has also been consistently far more reliable than the GFS itself thus far in 2020. Besides the upcoming synoptic pattern, I would also argue that the “clustering” of tracks strongly supports potential TC threats to the Carolinas, Mid-Atlantic, and/or New England sometime in mid-September. For example, besides the numerous impacts in TX and LA (northwestern Gulf Coast), principally Cristobal, Hanna, Laura, and Marco, we have already seen three or more TS+ impacts from SC to NY, including Bertha, Fay, and Isaias. A strong, negatively tilted trough centred over the Great Lakes with equally strong blocking just off the Eastern Seaboard—namely, centred near the Canadian Maritimes—would definitely support the notion of additional threats to the aforementioned region(s). The western Gulf and the Carolinas/Mid-Atlantic/New England definitely seem to be the preferred “hotspots” for U.S. impacts in 2020.

I agree, the troughs that have come have been negatively positioned still giving the US a threat because ridging across the Atlantic has stayed present more often than not.
So just because a strong trough may come down the US in about 10 days it does not mean many if any OTS tracks setting up. The only ones that I may see going OTS are the ones that may develop strong sooner just off of the CV Islands, eventually once the SAL outbreaks settle down and they track through a break in the ridge in the middle or eastern Atlantic.

Fully concur with all of the above. Most Atlantic seasons exhibit a pretty strong display of pattern persistence. I'm not even referring to the specific clustering of tropical cyclone tracks themselves, though as the season progresses they clearly exhibit what anomalous mid level ridging or troughing had broadly been in place for that season. It is plainly obvious to see that thus far 2020 has been a year where tropical storm tracks have been primarily influenced by predominant high pressure ridging across the breadth of the Atlantic from MDR all the way north into the northern latitudes AND extending well west into the Eastern CONUS.

Ironically, I see one similarity in conditions that ultimately impacted storm tracks in the 2005 Atlantic season and this years' storm tracks. If we just look at overall storm tracks for 2005 and 2020 (not quantity of storms), there's one big similarity and one big disparity between the two years. On the surface, most people would say that storm tracks from 2005 and 2020 have nothing in common. Okay, so the obvious dissimilarity were the broad "shot-gun" pattern of storm tracks during 2005 where damn near every square inch of the Atlantic basin was exposed to tropical cyclones tracking nearby. In 2005 storms tracked to the west, to the north, to the east, with a few storms even having a southerly component of motion for a short period of time. In 2005 storms formed practically everywhere including the Central Atlantic MDR, Caribbean and Southern Gulf but also throughout the sub-tropics too. 2020 storm tracks have been largely clustered along an east to west low latitude conveyor belt that has rounded it's turn roughly between 80W-90W with some tracks continuing north into S.E. Canada and the rest turning ENE around 35N. What the two seasons DID have in common that largely impacted storm tracks was the lack of meridianal kinks in the steering flow which we generally see each Hurricane Season. The steering flow for both years have been exceptionally zonal, without the typical semi-permanent mid Atlantic or E. CONUS trough. I call it the anti-Ninal Conde pattern LOL. Primary reason for 2020 storm tracks appearing so different from 2005 has been the anomalously strong mid level heights across nearly all of the Atlantic this year compared to 2005 having lower heights and weaker mid level height gradient across most of the Atlantic. One other likely contributing factor in 2005's "scatter-shot" storm tracks was likely the more conducive conditions for genesis throughout the entire basin better allowing development to occur and less hampered by dry air or particularly strong Easterly trades. Here in 2020 a broad range of very favorable conditions have been in place but particularly strong mid and upper level easterly trades have also resulted in much of the basin being hampered by large SAL incursions and dry mid level RH. Area's least affected by these negative conditions seem to be southernmost latitudes and westernmost longitudes and will probably continue to be area's most likely to exhibit best chances for quicker development and potential RI.

I have to agree with NDG and Shell that given the primary pattern we are in, it makes sense to assume that additional storm tracks will likely push very close to or track over the US Eastern Seaboard from the Carolina's northward potentially to New York or as far north as Maine. I'm sure that global models (especially the GFS) will continue to project long-range forecasts toward deeper trough bias as we inch toward Fall. Unfortunately, the models are taking longer then normal to correct themselves and have seemed to have less of a handle on mid-term time frame steering. On the broader scale the largely zonal flow will probably continue to give way to a negatively tilted long wave pattern extending southward from the Great Lakes and amplified ridging extending to the far West Atlantic, it's reasonable that some southerly steering component will increasingly play into the steering of storms approaching 75W-85W. Generally speaking that should imply a decreasing threat to East Coast Florida from storms approaching from the southeast. On the other hand, I also think we'll see an increase in development near the Lesser & Greater Antilles, West Caribbean and Eastern Gulf. That would suggest increased risk to Central America and Yucatan, and enhanced risk of southerly approach to Jamaica, Cuba, Florida and Northern Gulf regions (my guess is that risk to the Texas coast will diminish going forward - famous last words lol).