Dec 18-22 Potential Winter Wx Event

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Models have been consistent lately in advertising a significant weather maker moving into the midwest early next week. The setup is very similar to the major winter storm only weeks ago. This system however, will initially deal with strong dynamics, and COPIUS moisture, as well as much higher than average temps.. Therefore, we could see a fairly wide area of thunderstorms. possibly getting strong... During the period... Not seeing the cold push to be as extreme as in past model runs, but will have to watch for a change over to snow for accumulations! Dont want to get my neck chopped off so wont get too specific or go in to much detail.. But will have to watch closely!

As a note, that, as we did with the past system, winter precipitation can classify as a "significant precipitation event" and, thus, can be discussed in a FCST and NOW thread in the Chase Forecast forum. Also, for future reference:

Chase Forecast Forum rules said:
(9) Chase topics spanning multiple or ambiguous dates are prohibited, such as "FCST: This Weekend". Map Room is chronologically organized and is dependent on exact dates. Pick the most representative calendar date and post your message there. Commit to a date, and if it changes you can always move to another thread or start a new one.

I normally use the PM system to address issues such as this, but I figure we may have several more winter storms through the next few months, so I'll mention this to all.

This topic will pertain to the WINTER WEATHER aspect of the event. If a convective storm (i.e. deep moist convection that we typically chase) threat develops with this system, then a new FCST thread should be opened to address that threat. We typically prefer to use a thread in Weather and Chasing for events that are a good deal into the future (e.g. >5-7 days), since the forecast error potential is great. For example, the "pattern change coming?"-type of threads are allowed in the W&C forum, since date and event specifics cannot be addressed with much confidence a week or more in advance. In this particular case, we'll keep this discussion in this FCST thread since most models indicate a strong, high-amplitude upper-level trough and low-level cold front making their way into the central US next week (implying the potential for a significant surface cyclone).

The date chosen for the thread is based on the 12z GFS run from this morning, which shows a strong ~985mb low over the Great Lakes by 21/12z, with the threat for heavy snow from the central plains to the western Great Lakes.
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Well, I had a change-of-heart. I think the system being addressed in this thread is too far into the future that it really is a "wishcast" situation at this point (for those looking forward to winter weather). This thread can be moved into the Chase Forecast forum in a few days (by the end of the week) if it appears more likely that such a cyclone indeed will develop across the central US. There tends to be quite a bit of 'waffling' this far in advance, so informal discussion that may result is more fitting for W&C than a FCST thread.
I agree with the decision. It is still way out. Models cant decide on a track or southern desent of cold air intrusion. Do agree that it would be best to wait. Thank you sir.

Is this the system coming off the west coast you are talking about?
This system definitely holds some potential to give someone a better chance at a white Christmas, the ECMWF is favoring a more southern track with the system favoring some winter precip for the TX panhandle region however the GFS especially today’s 12Z favors a quite significant winter storm over the NE, KS and IA areas. Way to many discrepancies in the models and also to much time for things to change to get too excited but definitely worth monitoring model trends.
notice models are trending further north with heavy axis of precip and further soutward extent of cold air push. Yes, I agree. It definitely has potential.
just for the note the latest GFS is further southeast again! and colder. The trend looks to be, the low is taken further south before being cutoff and ejected into the plains
Lucky me!!! I'm heading up to the MSP area to get my mother in law and family for Christmas back here in Okla. on Wednesday the 20th I may leave a day early and enjoy the storm. I'll be following this close!

What happened!!

Looking at the 12Z GFS run, this model is up to its dastardly deeds once again and shoves all the precip. south and east of the OUN forecast area.
Hard to believe with so many previous runs being so consistent with a major bout of VERY MUCH needed rain here in cntrl Okla.

In addition, the system slated to move across the mid section of the country has all but vanished... I'm thinking this has to be an abberation of the the recent runs on the GFS..... hopefully.

models look somewhat similar with latest run. Slower seems to be the trend. With the GFS still all over the place. ECMWF has stayed somewhat stable. But slower and further southa and weaker is the trend
Can't live and die by the GFS!

I appreciate rdale's shock treatment on the reliance of one model. I sometimes get to wound up looking at that model and with my time constraints on our family computer.. sometimes I just don't have the time to dig into the complexities of deciphering the rest of the data.

Still, analyzing the ensemble data from 0Z thismorning, the Canadian, UKMET, ... and ooooh God, the GFS too... I'm guardedly optimistic of our rain chances next week here in Okla. and even a small window of opportunity of severe weather further east in Ark for the 20th. I just hope that the upper low doesn't move too much further north than expected or we'll get dry slotted here in cntrl Okla. Time will tell.

rdale you can't talk to Rocky like that, what's wrong with you?:eek:

Rocky I'm with you man,according to this mornings runs GFS and ECWFM are in pretty good agreement with the placement of the closed low and it looks like we can finally get some winter wx up here in NE on Wednesday and Thursday.
This system is so far out and winter wx gives us SO many notorious problems forecasting it that I think we would know a lot more if we waited until after this weekend. As of now - according to just the one run of the GFS - it looks like an all-rain event for anyone south of KS.

Look at the amount of spread in the ensemble GFS - it amazes me that people even think to get specific on placement when there is so much uncertainty... It is an absolute waste of time to make long range forecasts if you only look at one slice of the GFS.

There's a thing called "tact". I suggest you acqaint yourself with it.

I overlook a lot of these replies from you, but Rocky is the nicest guy you'll ever meet, and I can't sit here and watch you rake him over the coals on one of your typical, anal, angst-ridden shots.
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Seriously folks... Play nice! There's no reason to get chippy with other members. If you don't agree with someone's opinion, there's no need to become even the tiniest bit belligerent. Nobody should be too critical with anyone else, unless you can prove yourself infallible. Remaining cautious over a potential event that is seeing very high model spread is prudent in most cases. Regardless, let's not get too critical of each other.
I agree 100% with Rob in regards to using the ensembles. The truth is, the GFS is only ONE run of the entire ensemble suite... Why limit yourself to just one run? Most people don't know about ensembles (or even how to interpret them), so passing on that information is helpful.

I don't see any "coal raking" going on (at least from Rob), so either the posts have been deleted or I'm completely missing something (i.e. a personal grudge between members). Rocky took Rob's words as advice, just like everyone should...

Don't rake coals where there isn't a fire - you'll only make things worse.
No more posts about 'coal raking'. All discussion in this thread must pertain to the topic of the thread. Any posts that do not address the topic of the thread will be deleted.
Looks like some things are starting to gain some consistency through the latest runs. Looks like the firing line for the heaviest snows (as of now) would be from North Platte-Kearney-G.I. and points northeast from there. Some thoughts from OAX.....

Personally, I'm hoping that Low tracks further south. Why I'm cheering for a winter storm is probably only understood by the people who frequent a board like this. ;)

MODS: is this a Chase Forecasts: FCST thread yet?
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I agree with J.B., the models are coming into much better agreement now, so that should throw some much needed water on the aforementioned coals, thankfully.
This morning's AFD from BOU has some interesting thoughts in regard to the potential storm:

If the models continue to be as consistent as they were for this morning's run over the next couple days, it would be a fair assumption to say a significant snowstorm will hit the Front Range, High Plains and Central Plains beginning Wednesday afternoon and lasting into Thursday afternoon. It's too early to be precise on accumulation amounts, but given the amount of moisture this storm will have to work with and the forecast favorable upper air dynamics, I think localized storm totals in excess of a foot are a distinct possibility. The area that is appearing to be favored by the models to see this type of heavy accumulation is the plains of northeastern CO, eastern WY, and the NE Panhandle, and then areas north of I-80 further east. This could be a major headache for holiday travelers trying to fly out of Denver or Omaha or drive on I-80, I-25, I-70 or I-76 in the Wednesday/Thursday timeframe.
I'm REALLY hoping this pans out, as we need the moisture VERY badly. We've only had a measly 5 inches of snow since October.
And besides, I love a white Christmas as much as the next guy.
All I can say is this: Let it snow, let it snow, let it snow... :D
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I forgot to add the dates to my last fcst post... the possibility of a white christmas is due to the models projecting a snow/ice event from Sunday Dec 24th to Tue. the 26th. My apologies.

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It's not looking pretty here in Amarillo. We are already in a winter storm watch and ice accumulations could reach up to an inch before it's all said and done. Not to mention a possibility of sleet along with 2-4 inches of snow. I will probably be busy shooting video for the station on Tue. and Wed. so I should have some good footage for all to see.
While I haven't been watching this system with dedication, I have to say I think Mark might be correct about CO and to our east/northeast. Figures, since I'm supposed to fly out of DIA on Wednesday evening, I'm not feeling all too warm and fuzzy about it. Although the models are converging, the situation is complex, with a broad region affected by this system. If the NAM is correct, the areas indicated by Mark look like they will receive ample snowfall. Might even extend that region into W KS and SD. Also I think Jason might be right too, as models "converge", as it looks likely that there will be a corridor of heavy freezing rain/sleet through the TX panhandle. Now, how much snow will actually fall near the front range, in between the mountain maximum and the plains maximum? Seems the speed of this system may prevent prolonged deep upslope along the front range, keeping the snow totals somewhat modest in our area, thankfully in my selfish situation. But just an extra 12 hours of upslope winds around 700 mb could keep us stuck at the airport, and just a little change in the model could produce just that.
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