PHL Jan 11-12 Miller B Thread

[Bluescat1]

Mistakes happen, but you make some very valid points. They are legends on this board. They take their time out to post their thoughts, forecasts, etc. They could easily clean off their hands and be done with this board. Show them the proper respect please.

A+++

[phlwx]

Sorry, Ray. I just get bent at the bashing. I actually did know that. (sheepish)

You weren't the only one. I didn't call anyone out though.

Calling a premature bust or "what are they smoking" type posts are BS...would love to see them issue a forecast for 11 mil people and try to put all of the modeling and climo into consideration...

[famartin]

Could someone explain to me how any model that's bad at a certain point in time can correct itself and become accurate at a time later on? I'd think that once it had gotten inaccurate it'd only stay inaccurate or grow worse, but this statement seems to imply that the Euro can go from bad modeling in the <1 day range to good modeling in the several-day range!

The statement may have been made in context of other models. That's the only way it makes any sense.

[Tiburon]

Not sure if you are saying that the GFS is good or bad here.... but its #2 to the EC.

The GFS isn't a horrific model, it's just very prone to hiccups, and radical flip-flops from run to run. We all know and remember the days of the GooFuS model, overall it's verification isn't terrible, but these guys are looking at model suites and latching on to one or the other, or worse yet, just latching on to whatever the latest guidance happens to be.

"Wow! The NAM is a big hit! 6-12!"

"Ugh, the GFS is a miss! 2-4!"

"Hey, look at the EC! 4-8!"

"NAM sucks again! 1-3!"

All in 6 hours time.

[famartin]

My thinking hasn't changed for the upper bucks county area with this storm. Fearless forecast is 4-5"

snow on top of snow on top of snow, and cold through the extended with more nickel and dime chances and maybe more than that down the road. Turning into a very good winter enthusiasts month and we deserve it because January's have dissapointed for a good number of years.

Seriously, since January 1996 how many good januarys have there been?

Very few. Many January snowfall averages went down in the last 10 years.

[am19psu]

The GFS isn't a horrific model, it's just very prone to hiccups, and radical flip-flops from run to run. We all know and remember the days of the GooFuS model, overall it's verification isn't terrible, but these guys are looking at model suites and latching on to one or the other, or worse yet, just latching on to whatever the latest guidance happens to be.

"Wow! The NAM is a big hit! 6-12!"

"Ugh, the GFS is a miss! 2-4!"

"Hey, look at the EC! 4-8!"

"NAM sucks again! 1-3!"

All in 6 hours time.

The GFS has improved immensely since the upgrade in July. You may think it's a poor result, but I don't know how you can say it's been flip-flopping.

[Quakertown needs snow]

euro for that storm looks like an ice storm up your way...prob snow quickly to ice then rain for phl...shoots a primary to ky then develops a coastal right along the delaware beach and scoots it northeast

thanks tom... was worried for poconos ski areas at this point.. back to current event...

[weatherweather]

Could someone explain to me how any model that's bad at a certain point in time can correct itself and become accurate at a time later on? I'd think that once it had gotten inaccurate it'd only stay inaccurate or grow worse, but this statement seems to imply that the Euro can go from bad modeling in the <1 day range to good modeling in the several-day range!

I think its because their resolution isnt made for handling precise dynamics in a setup like this, which in later panels wouldnt make much of a difference

[famartin]

The GFS isn't a horrific model, it's just very prone to hiccups, and radical flip-flops from run to run.

Everything is prone to hiccups this winter, it seems. Even the EC as we saw not once, but twice in December. With this storm the steadiest model has been the GFS. EC has waffled back and forth a bit and the NAM has had wild swings.

It will be interesting to see if my parents wind up with 4", validating the GFS, or 8" validating the NAM.

[Tiburon]

"Mt. Holly may get some egg on their face, I really appreciate all the work they do and I know they work hard, but just like WE get burnt on model hugging, so too will THEY."

I was referring to them busting low, not a bust for the storm. Seems like you want to target and call out a lot of people all at once, as you can see from the my above quote, I was not being rude at all, just making an observation on present conditions and those modeled, and my interpretation. I don't understand why there is such an inflammatory response from people like you, it is quite trollish you know.

The surface low and intensity are clearly stronger, and further west, I certainly can't understand how you can call me out especially over an hour after the post, my comments were also in reply to the MM5 and other high rez mesoscale models, which have all indicated a stronger and closer to the coast evolution with this system. Kindly PM me if you have a personal problem with what I have stated.

What got the response from me was the bolded part of your statement. I'll continue this via PM.

[atownwxwatcher]

One must understand this is one of the most non-linear developing storms I have ever seen. ORH_wxman brought up 12/9/05 as similar system. This has such a huge dynamic tropoause and there will be folding--and the compact nature of this storm and non-linear development will result in erratic tracks both in the models--but in reality as well. Nobody knows where this will go exactly--and convection will be a key driver in development. Bad analogy here--but hurricanes do quite similar things with track. Weird wobbles, etc. Non-linear beasts like this are very challenging to track. NAM has actually been one of the better models and was the first to suggest this kind of rapid development.

Thanks for the comments in here. It seems like most have been ignoring it however..but i been following your posts in the NYC thread and you are indeed on top of your game!

[Harbourton]

Everything is prone to hiccups this winter, it seems. Even the EC as we saw not once, but twice in December. With this storm the steadiest model has been the GFS. EC has waffled back and forth a bit and the NAM has had wild swings.

It will be interesting to see if my parents wind up with 4", validating the GFS, or 8" validating the NAM.

I'm going with the 4" in Hopewell

[NaoPos]

This thread has become the laughing stock...let's keep the model performance/ hugging arguments somewhere else, please? Who would complain with 4-8? IN JAN!!!??? This is awesome

[famartin]

This thread has become the laughing stock...let's keep the model performance/ hugging arguments somewhere else, please? Who would complain with 4-8? IN JAN!!!??? This is awesome

After the 5 KU's in the last 13 months, some people have lost sight of reality

[Tiburon]

After the 5 KU's in the last 13 months, some people have lost sight of reality

Amen.

[phlwx]

One must understand this is one of the most non-linear developing storms I have ever seen. ORH_wxman brought up 12/9/05 as similar system. This has such a huge dynamic tropoause and there will be folding--and the compact nature of this storm and non-linear development will result in erratic tracks both in the models--but in reality as well. Nobody knows where this will go exactly--and convection will be a key driver in development. Bad analogy here--but hurricanes do quite similar things with track. Weird wobbles, etc. Non-linear beasts like this are very challenging to track. NAM has actually been one of the better models and was the first to suggest this kind of rapid development.

12.9 is a different beast for this area though since the track was generally over our region as opposed to up the coast. We were dealing with snow/mix but the storm was literally exploding as it moved through from west to east. For SNE, the impacts may end up being similar but the big question here was ptype more than how much.

Anyways, the NAM has jumped around a fair bit regarding track (moreso than the GFS) and also intensity...it seems to be handling the development of the storm poorly to me because it is a higher resolution model.

http://www.emc.ncep...._coast.4cyc.gif

http://www.emc.ncep...._coast.4cyc.gif

[Quakertown needs snow]

After the 5 KU's in the last 13 months, some people have lost sight of reality

what ray said.

if we didn't have last season then 4-6" would be a bundle of joy to all.

[SP]

After the 5 KU's in the last 13 months, some people have lost sight of reality

I am thinking since you did not fly in for this one....well......TTN has a chance

BTW..reality is reviewing this thread as I type.......

Your comment about the spread between the GFS and NAM is spot on....Monmouth spread is 4.4 GFS and 16.9 NAM

[baroclinic_instability]

12.9 is a different beast for this area though since the track was generally over our region as opposed to up the coast. We were dealing with snow/mix but the storm was literally exploding as it moved through from west to east. For SNE, the impacts may end up being similar but the big question here was ptype more than how much.

Anyways, the NAM has jumped around a fair bit regarding track (moreso than the GFS) and also intensity...it seems to be handling the development of the storm poorly to me because it is a higher resolution model.

http://www.emc.ncep...._coast.4cyc.gif

http://www.emc.ncep...._coast.4cyc.gif

With that date I didn't necessarily mean to consider its track, just its explosive development.

As for the NAM, it won't be as "consistent" as the GFS, it never will be. It isn't made to be either. The NAM is a non-hydrostatic mesoscale model, and as such, it requires much less aggressive filters. This is good and bad. Noise can creep up into the analysis and this is why the NAM can typically become garbage after 48 hours sometimes. However, as I said earlier regarding this storm, the GFS will not be able to handle it well. It isn't made to. GFS is a completely different beast, and in this case, the NAM gets far more consideration than the op GFS because of the extreme non-linear develoment and the compact nature of the low as well as effects of the deep DT and likely folding. The op GFS may be consistent, but why bother if it is consistently wrong?

[famartin]

With that date I didn't necessarily mean to consider its track, just its explosive development.

As for the NAM, it won't be as "consistent" as the GFS, it never will be. It isn't made to be either. The NAM is a non-hydrostatic mesoscale model, and as such, it requires much less aggressive filters. This is good and bad. Noise can creep up into the analysis and this is why the NAM can typically become garbage after 48 hours sometimes. However, as I said earlier regarding this storm, the GFS will not be able to handle it well. It isn't made to. GFS is a completely different beast, and in this case, the NAM gets far more consideration than the op GFS because of the extreme non-linear develoment and the compact nature of the low as well as effects of the deep DT and likely folding. The op GFS may be consistent, but why bother if it is consistently wrong?

Could you explain why the GFS handled the 12/26 bomb so well, as compared to how you think its handling this one?

[baroclinic_instability]

With that date I didn't necessarily mean to consider its track, just its explosive development.

As for the NAM, it won't be as "consistent" as the GFS, it never will be. It isn't made to be either. The NAM is a non-hydrostatic mesoscale model, and as such, it requires much less aggressive filters. This is good and bad. Noise can creep up into the analysis and this is why the NAM can typically become garbage after 48 hours sometimes. However, as I said earlier regarding this storm, the GFS will not be able to handle it well. It isn't made to. GFS is a completely different beast, and in this case, the NAM gets far more consideration than the op GFS because of the extreme non-linear develoment and the compact nature of the low as well as effects of the deep DT and likely folding. The op GFS may be consistent, but why bother if it is consistently wrong?

FWIW, the GFS has a weak low well off the eastern seaboard while Hatteras is already sub 1015 hpa. GFS is not doing too hot.

[IsentropicLift]

Whenever their is a MECS on the table, everyone naturally wants to be in the bullseye. People to the south and east of Philly need to realize that a typical la nina winter for philly tends to have very low snow totals which have already been surpased. Take a look at this link... http://www.erh.noaa.gov/er/phi/winter.html

It shows that on average Philly only gets 21.9" per winter and 13.8-15.9 in a mod or strong nina like we are currently seeing. To take it a step further, PHI has only had one 10.0"+ snowfall in a nina period. Keep in mind that the stats do not include this winter. Some people on here need to have a realitly check. It was not long ago that we were all complaining about the forecast for a warmer than average, lack of snow winter.

[Harbourton]

With that date I didn't necessarily mean to consider its track, just its explosive development.

As for the NAM, it won't be as "consistent" as the GFS, it never will be. It isn't made to be either. The NAM is a non-hydrostatic mesoscale model, and as such, it requires much less aggressive filters. This is good and bad. Noise can creep up into the analysis and this is why the NAM can typically become garbage after 48 hours sometimes. However, as I said earlier regarding this storm, the GFS will not be able to handle it well. It isn't made to. GFS is a completely different beast, and in this case, the NAM gets far more consideration than the op GFS because of the extreme non-linear develoment and the compact nature of the low as well as effects of the deep DT and likely folding. The op GFS may be consistent, but why bother if it is consistently wrong?

May I ask a question?

I understand mesoscale model. but what is non-hydrostatic?

[weatherweather]

dang hpc really pushin the qpf east

[baroclinic_instability]

Could you explain why the GFS handled the 12/26 bomb so well, as compared to how you think its handling this one?

The Christmas bomb was a different beast than this with the initial surface low tracking through the GOM. Latent heat release and convergence in the GOM played a large role in the eventual development, and the GFS did well in the 3 day range because it was really the first keying in on the GOM role. As I had said back during that event, the early ECM runs lost the storm as the southern stream wave petered out once we came within 4-5 days of the event. All guidance lost the storm OTS because the configuration of the trough did not allow for rapid cyclogenesis early enough....and all solutions were OTS. GFS, by day 3, keyed in on the strength of convection in the GOM and the low level mass response/surface convergence and associated latent heat release via condensation in the lower boundary of the atmosphere. Moreover, the globals continued to trend towards a more amplified Rockies ridge and a deeper diving backside jet streak. The "capture" of that surface low in the GOM primed rapid feedback cyclogenesis over the Gulf Stream due to latent heat release in the GOM owing to the mass response/convergence to the developing convection. GFS was the first to key in on all those factors coming into play--and as a result--I think it is safe to say it "performed" the best within the day 3 range. As for that storm, development was also highly non-linear, but not nearly as non-linear as this system. Rapid feedback with that storm developed off SC coast with a much more amplified wave. This storm is bombing well N of Hatteras with a S/W ejecting over the Gulf Stream in a nearly W-E fashion. While the Christmas storm featured signficant non-synoptic scale development including the ridiculous ageo jet circulation, this storm features an insane dynamic tropopause and a large fold. We are talking deepening of 20-30 hpa in 18 hours with a compact low smaller than LI. The low itself is getting close to sub-grid scale for the GFS and its spectral wave ~ 25 km resolution. The GFS won't be able to handle that type of non-linear development like it did for the Christmas storm.

[Delaware]

Baroclinic, what is your thinking on the storm?

[Tiburon]

The Christmas bomb was a different beast than this with the initial surface low tracking through the GOM. Latent heat release and convergence in the GOM played a large role in the eventual development, and the GFS did well in the 3 day range because it was really the first keying in on the GOM role. As I had said back during that event, the early ECM runs lost the storm as the southern stream wave petered out once we came within 4-5 days of the event. All guidance lost the storm OTS because the configuration of the trough did not allow for rapid cyclogenesis early enough....and all solutions were OTS. GFS, by day 3, keyed in on the strength of convection in the GOM and the low level mass response/surface convergence and associated latent heat release via condensation in the lower boundary of the atmosphere. Moreover, the globals continued to trend towards a more amplified Rockies ridge and a deeper diving backside jet streak. The "capture" of that surface low in the GOM primed rapid feedback cyclogenesis over the Gulf Stream due to latent heat release in the GOM owing to the mass response/convergence to the developing convection. GFS was the first to key in on all those factors coming into play--and as a result--I think it is safe to say it "performed" the best within the day 3 range. As for that storm, development was also highly non-linear, but not nearly as non-linear as this system. Rapid feedback with that storm developed off SC coast with a much more amplified wave. This storm is bombing well N of Hatteras with a S/W ejecting over the Gulf Stream in a nearly W-E fashion. While the Christmas storm featured signficant non-synoptic scale development including the ridiculous ageo jet circulation, this storm features an insane dynamic tropopause and a large fold. We are talking deepening of 20-30 hpa in 18 hours with a compact low smaller than LI. The low itself is getting close to sub-grid scale for the GFS and its spectral wave ~ 25 km resolution. The GFS won't be able to handle that type of non-linear development like it did for the Christmas storm.

Holy ****.

I'm impressed.

[IsentropicLift]

FWIW Mt. Holly has begun updating my zone in Morris County. I went from 3-7" tonight and 1-3" in the AM to 5-9" tonight and 2-4" in the AM. So 7-13" which is definitly close to my forecast of 10-16".

[Desnowlover]

Have gone from "SNIRGA" (borrowed from Mt Holly AFD) to light snow within last 5 minutes!

[am19psu]

Nice post, B_I. I think you know more about models than I do, so I'll defer to you here, but shouldn't the Euro be picking up on these processes as well, since its resolution is down to 15km? Or is it still hydrostatic and not picking up on some of the convective processes as a result?