2020 Global Model Runs Discussion (Out thru day 16)

[SFLcane]

12z GFS says hello Fall goodbye peak of the hurricane season.

https://i.imgur.com/WVbTNDj.png

I thought the gfs was out to lunch with this trof? It’s ok we can watch the peak of the season from a distance as this will no doupt weaken whatever little ridging there is and recurve any aew”s. GOM based on this run will be highly unfavorable for a while

[TheStormExpert]

12z GFS says hello Fall goodbye peak of the hurricane season.

https://i.imgur.com/WVbTNDj.png

It'd be nice if we see fronts like this during the winter months.

[weeniepatrol]

Lol, it's already been proven again and again and again that the GFS is utterly clueless this season. I will take the opposite of what it shows because that will verify better.

[crownweather]

Check out what's going on in the Western Pacific. The 2 typhoons aren't curving as quickly to the north and northeast as was progged by guidance just a couple of days ago.

This potentially tells me that the Central and Eastern US trough may not be as deep as the GFS model says. I think the WAR may hold off any troughs and lead to some "adjustments" westward with any tropical systems moving from the eastern Atlantic.

[AutoPenalti]

12z GFS says hello Fall goodbye peak of the hurricane season.

https://i.imgur.com/WVbTNDj.png

I thought the gfs was out to lunch with this trof? It’s ok we can watch the peak of the season from a distance as this will no doupt weaken whatever little ridging there is and recurve any aew”s. GOM based on this run will be highly unfavorable for a while

I can bet my house this strong of a trough ain’t happening.

[toad strangler]

I can bet my house this strong of a trough ain’t happening.

and I'll throw my camper in.

[NDG]

Check out what's going on in the Western Pacific. The 2 typhoons aren't curving as quickly to the north and northeast as was progged by guidance just a couple of days ago.

This potentially tells me that the Central and Eastern US trough may not be as deep as the GFS model says. I think the WAR may hold off any troughs and lead to some "adjustments" westward with any tropical systems moving from the eastern Atlantic.

I've been meaning to ask that question, those Typhoons seem be very far west to affect the patter, doesn't usually happens when they are closer to Japan and track NE north of them?

[SFLcane]

Regarding the GFS Part of that is probably the Pacific bias... There does seem like there will be PV under the ridge that will probably cause some shear and also keep the storms from plowing west.

[crownweather]

Check out what's going on in the Western Pacific. The 2 typhoons aren't curving as quickly to the north and northeast as was progged by guidance just a couple of days ago.

This potentially tells me that the Central and Eastern US trough may not be as deep as the GFS model says. I think the WAR may hold off any troughs and lead to some "adjustments" westward with any tropical systems moving from the eastern Atlantic.

I've been meaning to ask that question, those Typhoons seem be very far west to affect the patter, doesn't usually happens when they are closer to Japan and track NE north of them?

Yeah, when a typhoon passes just east of Japan, you can bet the farm that you're going to see a trough build in the Eastern US in about 8-14 days and curve anything out. Since we're seeing these two typhoons head for Korea or perhaps southern Japan, it could potentially mean that areas from the E Gulf Coast to the FL/GA/Carolina coast could be at risk from a direct impact in 8-14 days.

[SFLcane]

12z GFS says hello Fall goodbye peak of the hurricane season.

https://i.imgur.com/WVbTNDj.png

I thought the gfs was out to lunch with this trof? It’s ok we can watch the peak of the season from a distance as this will no doupt weaken whatever little ridging there is and recurve any aew”s. GOM based on this run will be highly unfavorable for a while

I can bet my house this strong of a trough ain’t happening.

Hope you guys don’t loose your homes.

[SFLcane]

It does seem to maybe be overdoing the trof. we’ll see.

[DestinHurricane]

Check out what's going on in the Western Pacific. The 2 typhoons aren't curving as quickly to the north and northeast as was progged by guidance just a couple of days ago.

This potentially tells me that the Central and Eastern US trough may not be as deep as the GFS model says. I think the WAR may hold off any troughs and lead to some "adjustments" westward with any tropical systems moving from the eastern Atlantic.

I've been meaning to ask that question, those Typhoons seem be very far west to affect the patter, doesn't usually happens when they are closer to Japan and track NE north of them?

Yeah, when a typhoon passes just east of Japan, you can bet the farm that you're going to see a trough build in the Eastern US in about 8-14 days and curve anything out. Since we're seeing these two typhoons head for Korea or perhaps southern Japan, it could potentially mean that areas from the E Gulf Coast to the FL/GA/Carolina coast could be at risk from a direct impact in 8-14 days.

That's interesting. I had no idea that typhoons in the wpac influenced the Atlantic. What happens if the Typhoons shift even further west and into the yellow sea or right on the west coast of the Korean peninsula?

[AxaltaRacing24]

It does seem to maybe be overdoing the trof. we’ll see.

personally, i see 0 reason why that trough verifies. this same stuff happens in winter with the gfs.

[gatorcane]

The GFS has support from the CMC on this:

[AxaltaRacing24]

:uarrow: The GFS has support from the CMC on this:

https://i.postimg.cc/qMHbF9QZ/gem-T2ma-eus-34.png

and that changes exactly nothing for me. it's still not going to be that strong in my opinion. especially based on current trends.

[SFLcane]

Might wanna head over to the thread for the wave exiting Africa. GEFS just got real interesting!

[mlfreeman]

On the one hand, 384 hours on the GFS 12z today.
On the other hand, 2020.

[USTropics]

Always love the WPAC teleconnections and how they impact large scale steering patterns over NA. Models show varying solutions, and I'll do my best to break down what exactly is occurring. First, here is a 48 hour forecast by the ECMWF showing our two typhoons in the WPAC. I've included some shrewd outlines of their eventual track (purple track is Maysak, blue track is Haishen).



Now let's move out 48 hours in time (96 hour forecast), and we'll see Maysak has a weak signature here on the 500mb chart as it becomes extra tropical and begins to interact with the North Pacific jet stream. Essentially what we'll see is an amplification of the high pressure to the NE (labeled H1), which will then amplify the cutoff low towards the east (labeled L1). Haishen is also seen here as a potent Typhoon on the same trajectory as Maysak:



Now let's move out 3 more days (144 hour forecast). We've had this trickle down effect, where H1 became pumped up, amplified L1, which is now creating a sort of Omega block pattern with the high pressure off the NW coast of the United States (labeled H2). We also have our longwave trough over the United states (labeled L2). In addition, we have Haishen repeating the process (circled in green) and this disturbance in the EPAC (circled in pink) that is just enough of a signature to prevent H2 from expanding much to the south:



End result (168 hour forecast on the 00z ECMWF), a cutoff low forms (L2, green arrows show it cutting off) on the backend of the longwave trough, and a lot of this can be contributed to the presence of another high pressure area to the east (labeled H3). This is where model solutions really begin to vary, as the GFS has the entire longwave trough negatively tilting and rotating all the way down to the GOM before finally lifting out to the NE. Meanwhile, as you can see the ECMWF instead has a cutoff low that forms, and the longwave trough passes over the top of the high pressure area (H3):



As Crownweather stated, and in my personal experience, a cutoff low forming and diving towards the SW United States seems more realistic (we typically see a more chaotic weather pattern over NA and the EC when these typhoons recurve towards the east of Japan). Again this is a 7+ day forecast by all the models, so a lot will change before we end up with an actual solution.

[NDG]

12z Euro so far is coming in similar to last night's run, with the trough negatively tilted towards the Rockies into the 4 corners area. Is standing its ground against the GFS.

BTW, 12z GEFS is much closer to the 0z EPS ensembles than to the 12z GFS Operational run.

[TheProfessor]

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.