2021 Global Model Runs Discussion (Out thru day 16)

[tolakram]

I didn't see the 12Z Euro posted

Starting at 48 hours

[aspen]

I didn't see the 12Z Euro posted

Starting at 48 hours

https://i.imgur.com/VKm4WSj.gif

Strange to see the Euro being as or more aggressive than the GFS after its abysmal performance last year.

Speaking of the GFS, the 18z run shows that early September MDR system, but doesn’t develop it until September 3rd/4th.

[SoupBone]

I didn't see the 12Z Euro posted

Starting at 48 hours

https://i.imgur.com/VKm4WSj.gif

Strange to see the Euro being as or more aggressive than the GFS after its abysmal performance last year.

Speaking of the GFS, the 18z run shows that early September MDR system, but doesn’t develop it until September 3rd/4th.

Yeah it wedges it between two areas of high pressure, and anywhere from Southern Texas to the Florida Panhandle would be in play.

[SFLcane]

Oh boy gfs…

Has long range wave off Africa heading towards northern islands as a potential hurricane. Miss trof and continues west

[aspen]

Oh boy gfs…

Has long range wave off Africa heading towards northern islands as a potential hurricane. Miss trof and continues west

It’s the same wave the Euro and EPS develop around August 31st/September 1st. Nearly 10 days out, but the timing hasn’t been pushed back.

[Iceresistance]

18z GFS features a MDR system to start September, at least it's compact & weakens as it gets closer to the Lesser Antilles . . .

[AutoPenalti]

18z GFS features a MDR system to start September, at least it's compact & weakens as it gets closer to the Lesser Antilles . . .

https://s9.gifyu.com/images/gfs_mslp_pcpn_atl_fh216-384.gif

Hmm, why did it weaken?

[NevadaFan18]

18z GFS features a MDR system to start September, at least it's compact & weakens as it gets closer to the Lesser Antilles . . .

https://s9.gifyu.com/images/gfs_mslp_pcpn_atl_fh216-384.gif

Hmm, why did it weaken?

Dry air intrusion due to the outbreak of Saharan Dust poleward of it and it's vulnerability as a compact cyclone as mentioned above

[toad strangler]

18z GFS features a MDR system to start September, at least it's compact & weakens as it gets closer to the Lesser Antilles . . .

https://s9.gifyu.com/images/gfs_mslp_pcpn_atl_fh216-384.gif

Hmm, why did it weaken?

Matters as much as it blowing up a 905 mb monster at that hour.
Not much.

[Cpv17]

18z GFS features a MDR system to start September, at least it's compact & weakens as it gets closer to the Lesser Antilles . . .

https://s9.gifyu.com/images/gfs_mslp_pcpn_atl_fh216-384.gif

Hmm, why did it weaken?

Matters as much as it blowing up a 905 mb monster at that hour.
Not much.

I’m not sure the GFS is capable of blowing up a storm of that magnitude any longer tbh.

[Iceresistance]

Hmm, why did it weaken?

Matters as much as it blowing up a 905 mb monster at that hour.
Not much.

I’m not sure the GFS is capable of blowing up a storm of that magnitude any longer tbh.

Well, it did just that to Surigae as a Sub-900 Monster in April 2021 in the WPAC . . .

[Hammy]

18z GFS features a MDR system to start September, at least it's compact & weakens as it gets closer to the Lesser Antilles . . .

https://s9.gifyu.com/images/gfs_mslp_pcpn_atl_fh216-384.gif

Hmm, why did it weaken?

GFS seems to fill the Atlantic with PV streamers by early September.

[Cpv17]

Matters as much as it blowing up a 905 mb monster at that hour.
Not much.

I’m not sure the GFS is capable of blowing up a storm of that magnitude any longer tbh.

Well, it did just that to Surigae as a Sub-900 Monster in April 2021 in the WPAC . . .

Me personally, I haven’t seen the GFS blow up an Atlantic storm in a hot minute! It used to do it quite often and was very entertaining!

[Teban54]

Hmm, why did it weaken?

Matters as much as it blowing up a 905 mb monster at that hour.
Not much.

I’m not sure the GFS is capable of blowing up a storm of that magnitude any longer tbh.

Didn't GFS just show a pressure of 951 or something for the second WCar system (not future 99L) a few runs ago? Not exactly sub-900, but it's certainly not bearish on everything.

[ROCK]

Got to love that Euro run…

[SoupBone]

The GFS has been nothing but consistent, I'll give it that. If it busts with this one, it will bust spectacularly.

Holds that ridge in place.

[Shell Mound]

18z GFS features a MDR system to start September, at least it's compact & weakens as it gets closer to the Lesser Antilles . . .

https://s9.gifyu.com/images/gfs_mslp_pcpn_atl_fh216-384.gif

Hmm, why did it weaken?

GFS seems to fill the Atlantic with PV streamers by early September.

Why? Wouldn't the TUTT tend to weaken by then? A storm nearing the Islands around the climatological peak of the season during -ENSO should be expected to strengthen rather than encounter a TUTT and weaken. I don't understand why the TUTT should be so persistent despite a conducive background state.

[Hammy]

Hmm, why did it weaken?

GFS seems to fill the Atlantic with PV streamers by early September.

Why? Wouldn't the TUTT tend to weaken by then? A storm nearing the Islands around the climatological peak of the season during -ENSO should be expected to strengthen rather than encounter a TUTT and weaken. I don't understand why the TUTT should be so persistent despite a conducive background state.

Obviously we won't know until it plays out but at least up to this point, the GFS (and related CFS for that matter) seems like it's been overstating the shear and TUTT all season.

Meanwhile, on top of the Gulf system and 97L having unanimous agreement, both the Euro and Canadian are showing two MDR systems in early September.

[kevin]

The euro 00z ensemble has quite a few members into Texas, 19 to be precise so that means that 37% (19 out of 52) of all members have a TS into Texas which is quite substantial given the timescale. 23 other members take the TS into Mexico 23. This also means that only 10 of the 52 members (19%) show no (landfalling) storm, which thus heavily seems to favor development considering how reluctant the euro has been earlier this year with storms that eventually did form. Also look at the MDR, seems like the euro is finally waking up the beast.

[cycloneye]