2018 Tropics: Global Model Runs Discussion (Out to day 16)

[Aric Dunn]

THe gfs is still getting the vorticity and broad circulation going on the 10th.. been supper persistent with that.

[chaser1]

As I see it, the primary "tell" will be whether or not the lower pressures in the W. Caribbean actually verify such as the GFS is forecasting. The EURO never shows W. Carib. SLP ever dropping below 1012 mb north of 15N. Assuming that we begin to see the lower sea level pressures that the GFS is indicating, then it would seem to boil down to whether upper level conditions are conducive enough for a MLC to develop and co-locate with a deepening LLC (that isn't being driven west/northwest by strong easterly trades). I don't think that dry air inhibiting convection down there would be an issue. If any developing (or secondary) surface low begins to develop but continuously gets driven into Central America or Yucatan, than the EURO (and other models) might have better forecast the strength and evolution of the W. Atlantic building heights. Should genesis occur and a T.D. or T.S. actually develop.... well then it would be fairly obvious that the GFS had a better handle on the orientation and evolution of the surface to mid level flow by not building heights westward within the 5-8 day time frame. Seems to me that if the latter proves out that this might suggest a continued long wave pattern that would seem to extend north to south, perhaps from (or East) of the Upper Midwest, southward to the Central or E. Gulf area.

[NDG]

Bottom line, it appears that the EURO and the GFS keep pretty strong 500mb heights east of Florida. Where the two models seem to diverge is around the 120 hr. point. The EURO appears to build the pretty deep ridge from the surface up to 500 mb. westward with time. Meanwhile, the GFS does not build the surface reflection westward and continues to leave a portion of the monsoon trough to extend into the W. Caribbean and Central America. The GFS also indicates a stout 594 ridge E. of Florida that does not appear to migrate westward. It's large round orientation results in a deep south to north steering pattern from the W. Caribbean and into the Gulf which logically would want to steer any MLC poleward (assuming a somewhat vertically stacked system were in place).

Good point, the Euro has been wanting to build up h50 heights across the western Caribbean/FL area which eventually do not come to fruition.

[LarryWx]

The 12Z EPS, fairly similar to prior runs, has only very limited support for a TC genesis with the vast majority of its 51 members with lows that are either nonexistent or weaker than 1004 mb. Suffice it to say we continue to have a model war, which makes this extra interesting to follow. Which models will win and lose? Stay tuned for the next epiosode!

[caneman]

I've not seen anything from the Euro thus far this year to lead me to believe that have a good handle on future cyclogenesis. Am I worng

[CyclonicFury]

18z GFS MUCH weaker and farther west

[tarheelprogrammer]

18z GFS MUCH weaker and farther west

Looks like shear and land interaction get it. Which would be nice. An active EPAC is usually a no go for the GOM. Or am I wrong in assuming that?

[chaser1]

18z GFS MUCH weaker and farther west

Looks like shear and land interaction get it. Which would be nice. An active EPAC is usually a no go for the GOM. Or am I wrong in assuming that?

Could well imply a weaker decapitated system indeed; that would certainly fall in line with the other models in recent runs. Or, it could just be a wonky 18Z run. Thats where run-after-run continuity is a more accurate indication either way (especially if/where ensemble members are still trying or even increasingly attempting to blow up a storm, however are more greatly scattered)

[Twisted-core]

https://imgur.com/wjERbDd

Looking a decent chance for something on the global models.

[Aric Dunn]

00z ICON starts out with vorticty in the Sw Carrib. keeps it broad with a lot of convection then as it reaches the central gulf its starts to organize more.

[Weather150]

00z ICON starts out with vorticty in the Sw Carrib. keeps it broad with a lot of convection then as it reaches the central gulf its starts to organize more.

Looks to be the first ICON run to fully develop a tropical system.

[Aric Dunn]

CMC is very fast with development in the SW carrib starting on the 10th then moving pretty quick nnw. model trend is leaning towards the development of some kind starting from the SW carrib. where in the process it actually gets designated is variable.

now the only model left is the Euro.. lol

by morning we will likely see a small percentage from the NHC. 0 - 20% probably

[Weather150]

00z GFS is more south and west than the 18z run.

[stormreader]

The well-known June hurricane of 1934. Killed thousands in Central America (flooding) before heading to the northern gulf coast. Article I read said that there was also a May tropical storm that year. It made landfall along the central La coast. At times it had Cat 2 strength, but made landfall at Cat 1 according to this article.
https://en.m.wikipedia.org/wiki/1934_Ce ... _hurricane

[Aric Dunn]

both the cmc and gfs have shifted towards the central and western gulf now..

[drezee]

both the cmc and gfs have shifted towards the central and western gulf now..

I agree with Joe B from three days ago. The GFS will cave as always. This will likely be a BoC mess heading toward Tampico or Brownsville.

[TheStormExpert]

Yup, was always suspicious of anything developing on the Atlantic side with the East Pacific being active. Just like that the GFS caves to the Euro, never underestimate the Euro.

[Kingarabian]

both the cmc and gfs have shifted towards the central and western gulf now..

I agree with Joe B from three days ago. The GFS will cave as always. This will likely be a BoC mess heading toward Tampico or Brownsville.

His theory makes some sense. Low pressure over in the EPAC and Mexico, higher than normal pressure east of the Bahamas. Not much space for central GOM development other than the BOC.

[boca]

Yup, was always suspicious of anything developing on the Atlantic side with the East Pacific being active. Just like that the GFS caves to the Euro, never underestimate the Euro.

The GFS developes the storm just in later frames but I think it’s in the process of caving in. Will see what happens at 12pm today.

[TheStormExpert]

Yup, was always suspicious of anything developing on the Atlantic side with the East Pacific being active. Just like that the GFS caves to the Euro, never underestimate the Euro.

The GFS developes the storm just in later frames but I think it’s in the process of caving in. Will see what happens at 12pm today.

06z tries to pull a stronger version of Debby (2012) but I'm not buying. If anything the GFS MAY be hinting at what's to come August, September, and October with a potentially more active GoM similar to 1985.