Texas Winter 2017-2018

[wxman57]

All of you must get one h*ll of a headache trying to figure all of those out!! LOL!!

That's particularly true when using them to predict a hurricane's track. We'll be looking at over 100 different possible tracks. In that case, averaging the ensemble members plus the operational runs often produces quite a good forecast track. With other weather, taking a look at the "ensemble mean" (average), can provide valuable info.

[missygirl810]

Yes, ensembles are typically more accurate especially at longer ranges (beyond 4 or 5 days).

I wouldn't say that ensembles are, individually, more than the operational runs. An ensemble is a number of extra runs of a model, like the GFS. The GFS has 20 ensemble members (runs). Each of the 20 ensemble members is run with slightly different initial conditions, to try to take into consideration the uncertainty in the initial atmospheric conditions. To save time, these 20 GFS ensemble members are run at a lower resolution than the operational run. As a whole, the ensemble members provide a range of uncertainty in the operational run. It IS true that averaging a number of ensemble members can often produce a better overall forecast than the operational run. But just because a few of the 20 GFS ensembles say snow doesn't make snow more likely. It's the average that counts.

By the way, the Canadian model also has 20 ensemble members. The ECMWF has 51 members, 50 run with slightly different initial conditions and 1 run with the same initial conditions as the operational run but run at the lower resolution of the other 50 members.

I wanted to make my post along these lines but my 2 year old was not patient enough for that. Thanks for elaborating.

Yeah, they don't huh lol. My youngest is 14 and still the same way now lol.

[missygirl810]

All of you must get one h*ll of a headache trying to figure all of those out!! LOL!!

That's particularly true when using them to predict a hurricane's track. We'll be looking at over 100 different possible tracks. In that case, averaging the ensemble members plus the operational runs often produces quite a good forecast track. With other weather, taking a look at the "ensemble mean" (average), can provide valuable info.

That must be why we see the spaghetti models on TV.

[Ralph's Weather]

18Z GFS has the ridge oriented oddly from the GoA to the Bering Sea which changes the trajectory of things downstream sending things further east than previous runs.

[starsfan65]

18Z GFS has the ridge oriented oddly from the GoA to the Bering Sea which changes the trajectory of things downstream sending things further east than previous runs.

What does that mean?

[Ralph's Weather]

18Z GFS has the ridge oriented oddly from the GoA to the Bering Sea which changes the trajectory of things downstream sending things further east than previous runs.

What does that mean?

No aignificant storms around here after Tuesday

[cheezyWXguy]

18Z GFS has the ridge oriented oddly from the GoA to the Bering Sea which changes the trajectory of things downstream sending things further east than previous runs.

While I agree, it is worth noting that the trough is generally deeper and less progressive this run, leading to Texas being colder after 12/24 than the previous run. Seems to me like a cautiously optimistic development, but still wouldn’t put much stock in it, as these models clearly have a lot more shifting to do

[starsfan65]

18Z GFS has the ridge oriented oddly from the GoA to the Bering Sea which changes the trajectory of things downstream sending things further east than previous runs.

While I agree, it is worth noting that the trough is generally deeper and less progressive this run, leading to Texas being colder after 12/24 than the previous run. Seems to me like a cautiously optimistic development, but still wouldn’t put much stock in it, as these models clearly have a lot more shifting to do

What about Thursday and Friday?

[Brent]

Im losing interest in Friday tbh unless something drastic changes i think the focus is shifting more towards Christmas and beyond

The issue with that is were back to being out in fantasy land. Kind of frustrating

[bubba hotep]

18z GEFS is interesting, this is as good as it has looked in a while now. I wonder if we will see the 00z models trend towards a solution more favorable of winter wx?

[starsfan65]

Im losing interest in Friday tbh unless something drastic changes i think the focus is shifting more towards Christmas and beyond

The issue with that is were back to being out in fantasy land. Kind of frustrating

Don't give up hope!!

[bubba hotep]

Im losing interest in Friday tbh unless something drastic changes i think the focus is shifting more towards Christmas and beyond

The issue with that is were back to being out in fantasy land. Kind of frustrating

Remember, the rain last night and the system coming up on Tuesday were basically missed by the models until just a few days out. The models were really struggling with how to handle this next system before locking in on a more compact and vigorous vort.

[aggiecutter]

Analogs and pattern is all that matters. Looking at weather models is like asking a drunk monkey what the weather is going to be next week.

[Brent]

18z GEFS is interesting, this is as good as it has looked in a while now. I wonder if we will see the 00z models trend towards a solution more favorable of winter wx?

http://models.weatherbell.com/gefs/2017 ... _tx_40.png

Looks like quite a few have the Christmas storm or the day after

[JDawg512]

Im losing interest in Friday tbh unless something drastic changes i think the focus is shifting more towards Christmas and beyond

The issue with that is were back to being out in fantasy land. Kind of frustrating

Remember, the rain last night and the system coming up on Tuesday were basically missed by the models until just a few days out. The models were really struggling with how to handle this next system before locking in on a more compact and vigorous vort.

Agreed^^^

[aggiecutter]

[Ralph's Weather]

The models seem to be struggling with the extreme -EPO. Last week models were all about a major SW trough and thus weekend it is all about the huge surface high on the Plains. Something big is happening they just have not figured out what. I'll go with a combo of the ideas.

[bubba hotep]

18z GEFS is interesting, this is as good as it has looked in a while now. I wonder if we will see the 00z models trend towards a solution more favorable of winter wx?

Looks like quite a few have the Christmas storm or the day after

12z Euro EPS had 14 members with winter wx on Christmas Eve or Day at DFW. So there are still signs of a Christmas system out there in the ensembles.

[Quixotic]

FWD AFD referred to the initial surge of arctic air as being extremely shallow. It was giving the models fits in their opinion. They seemed to favor the deeper colder air arriving after Christmas.

The models seem to do a decent job on these shallow air masses as we get closer. It’s going to be a wild ride.

[iorange55]

Yeah, I think we see a shift in the models tonight. I’m betting on the Christmas storm right now.