2020 Global Model Runs Discussion (Out thru day 16)

[NDG]

GEFS & GEFS-Para both say not so fast Mr. GFS Operational of shutting off the GOM, they show possible threats to the US on their 7-15 day range.
GEFS-Para more so than the GEFS.

[sma10]

Models showing that the waves exiting Africa the next several days have decent chance of development, but bring them to screeching halts over the central atlantic - very strange for early Sept?

['CaneFreak]

As always I would advise using the ensemble forecasts instead of day to day deterministic runs. Knowing biases as well will also help deciphering models. Anyways I think we're going to continue to see storms struggle in the MDR if that mid-level low forms. That low will also keep storms from recurving if they don't take an early exit when they leave Africa, which is an additional concern. As for biases we know that the GFS tends to overdue troughs and is usually the more progressive models. Meanwhile the Euro tends to overdue ridges and will sometimes favor blocking a bit too much. In all likelihood we'll see something in between, which suggests possible Florida EC and U.S EC threats when storms are approaching from the east. Storms in the Caribbean would be pulled into the Gulf like Charley, Ivan, Marco, etc. However, since this pattern is dependent on two tropical cyclones, we'll need to wait and see what they do, the further wester they recurve, the further west we'll likely see the trough setup and the more likely we'll see a cutoff low develop, which would open the whole GoM up for waves coming off of Africa.

To put it plainly I don't like the look of this pattern with combination of the wave train that the models are starting to show. As stated above, any storm that doesn't take an early exit to the north, assuming that mid-level trough does form in the Atlantic, will likely be stored towards the U.S without an exit route until the storm either gets too close to comfort, or landfalls. Then there's both the GEFS and GEPS showing a large upper level anticyclone developing off the African coast for waves to travel right into to help keep them organized. Depending on how much wind shear we see, we could have a case where waves have well developed MLCs, but LLCs struggle due to shear until the storms get further west where they can then go off under better conditions.

Sir I'm going to bump this post because I agree and share your same concerns. If you look at many of the ensemble forecasts for days 8-10 including the GEFS, GEFS-Para, GEPS, you will see a similar pattern. Trough in the OH Valley & Great Lakes with a ridge over the Northwest Atlantic into Newfoundland. That's a scary pattern folks. Let's hope that the Central Atlantic trough shown on some of the Ensemble forecasts holds and we can get storms to turn out to sea. Otherwise, it's going to be a long month because all models show the African Wave train rolling this month.

[gatorcane]

12Z parallel GFS shows widespread activity out over the open Atlantic mostly recurving:

[SFLcane]

Recurve parade this afternoon on most of the models.

[CyclonicFury]

Recurve parade this afternoon on most of the models.

Hope it stays that way - I'd love a nice recurving Cabo Verde hurricane to track that doesn't affect anyone!

[aspen]

12z GFS-Para run has a long, exciting future for one of the currently active eastern Atlantic waves (it's difficult to tell which one) past 200 hrs.

120 hrs


180 hrs


216 hrs


270 hrs


360 hrs


You can also see the Gulf system it and the CFS have been showing for mid-September in the final image.

['CaneFreak]

Now that I can believe based on the upcoming pattern. It's going to be an interesting month.

[Hypercane_Kyle]

 https://twitter.com/webberweather/status/1301270460211040262

[emeraldislenc]

I keep getting mixed signals from different people here on this site. Guess we will just have to wait and see

[SFLcane]

[DestinHurricane]

18Z GFS brings a weak TS to FL straights irma track but goes poof.

[toad strangler]

I keep getting mixed signals from different people here on this site. Guess we will just have to wait and see

Welcome to S2K

But in all fairness, it's hard to put much weight in modeling this year. No One saw this coming.

[sma10]

https://i.postimg.cc/T3M2NLNj/DD88-D68-A-C29-E-4-A87-8899-01-FED000781-F.gif

Noteworthy in that this run has the lead system quite a bit SW at 120hrs than the 12z run. Looking to see if the model solutions of a very slow/stall motion will verify

[floridasun78]

https://i.postimg.cc/T3M2NLNj/DD88-D68-A-C29-E-4-A87-8899-01-FED000781-F.gif

that likely 91L

[gatorcane]

Speaking of the GFS, it insists some chilly air for early-mid September will penetrate all the way down into the northern Gulf:

[Spacecoast]

It depends on what you are referring to. I'd imagine you are talking about CV threats from the U.S., which does often wind down after mid-September. However, in a -ENSO year like 2020, the Caribbean region will need to be watched in October for a potential threat. Florida landfalls in October remain common.

Besides...this has not been a quiet season for U.S. threats at all. We've seen seven named storms, three hurricanes and one major hurricane make landfall in the US alone. While Florida has been spared so far, the rest of the basin hasn't been lucky.

As for the season as a whole, it's September 2, not November 2. We haven't even hit the climatological peak yet (which is in 8 days).

My guess is that we will get 4-10 more named storms, 3-7 more Hurricanes, and 2-5 more Major Hurricanes.
I am 70% confident of that prediction, because it is NOAA's forecast, and their stated C.I.

If I wanted to be 90% confident, I could also predict something like: 1-15 more named storms, 0-15 more Hurricanes,
and 0-10 more Major Hurricanes. But that prediction (although more likely) is so vague, it would be useless.

I guess that is why NOAA, et al use the 70% statistical confidence interval, rather than the 90-95% C.I, used in other disciplines.

[crownweather]

Speaking of the GFS, it insists some chilly air for early-mid September will penetrate all the way down into the northern Gulf:

https://i.postimg.cc/Hsv2vZzc/gfs-T2ma-eus-32.png

If the GFS model is right and we do see that big of a chill into the northern Gulf of Mexico, I will donate $50 to Storm2K.

[sma10]

Speaking of the GFS, it insists some chilly air for early-mid September will penetrate all the way down into the northern Gulf:

https://i.postimg.cc/Hsv2vZzc/gfs-T2ma-eus-32.png

If the GFS model is right and we do see that big of a chill into the northern Gulf of Mexico, I will donate $50 to Storm2K.

Yeah let's see what happens. GFS predicts low of 48 in New Orleans on Sep 10. Record low for date is 62.

[gatorcane]

It’s not just how cool the GFS gets but look how long the GFS keeps the cooler anomalies around for, nearly a week! SSTs would take a serious hit if this happens: