Tuesday, December 13, 2011

December 20 MAJOR Snow Event (Updated 12/13)

Confidence: Medium-High
Snowday Chance: Low-Medium

This is a special briefing on a potentially MAJOR winter storm for the December 20th timeframe. This briefing comes as the 'King' of weather models (ECMWF) is printing out a snowstorm for cities such as Chicago, Detroit in the Midwest. What is even more astounding is how the ECMWF and ECMWF Ensembles match up at this point in time. Below is an image comparing the ECMWF ENS and ECMWF model itself at hour 168.
The similarities (minus the strength) at this point in time, especially with low placement, are very encouraging to my eyes that this may turn out. While we still have the GFS and other models to look at, keep in mind that the ECMWF ensembles have 51 different members coming together to produce a solution. If these 51 members still find a very similar solution, there is definitely some interest in that.
Another aspect to look at is the ECMWF's snowfall forecast. Here's the snowfall forecast at hour 168, the same hour as the images above.
The ECMWF is printing a band of very heavy snow to interact with the Midwest. It even appears to be targeting cities such as Chicago and Detroit right in the heaviest snowfall area. Our confidence level in this event is currently at a medium-high level right now, as shown at the top of the page. The reason we have the snow day chance level low is obviously due to the fact that this event is over 5 days away. Here's our model solution.

Model: ECMWF/ECMWF Ensembles
Reason: Ensembles and model are in very good agreement

38 comments:

AJ said...

How much snow will Valparaiso,Indiana get? Will it get as much as Chicago?

Andrew said...

If this verifies, Valparaiso would not get nearly as much snow as Chicago would get.

AJ said...

Do you think it will possibly change to getting what Chicago could get?

Owen12789 said...

From the looks of it Central Illinois is going to get hit. Do you have any idea how much snow that might be?

AJ said...

My area is always on the outside of the storm by about 20 miles and Chicago is always in the center! It is like mother nature is trying to tease me.

Andrew said...

AJ: The models will fluctuate, but the ensembles and model agreements make me wonder if they will dramatically change.

Owen: The legend should give you a good idea, plus an inch or two.

AJ said...

We still have about a week.A lot of things can change.

AJ said...

Maybe the storm will take a stronger turn.

Anonymous said...

Way too early to be too confident with this storm. Still a whole week. Maps are pointless right now.

Andrew said...

An agreement between model and ensembles this well and this far out is unusual. Things will change, but again, this is unusual.

Eddie said...

How much snow would detroit get

Andrew said...

Deoending on the ultimate track, Detroit might get some snow.

However, to AJ as well, this is a very sharp line between rain and snow, and snow may fall in places that are currently not projected to get snow. In a bigger scale, this event is still several days away.

Mike Paulocsak said...

Hello Andrew.What about January? Do you think Ohio will get in any snowstorms?I heard that the pattern is supposed to switch to the east.This to my thinking,would that the jet stream would buckle and steer the storms away from the midwest.What are your thoughts? What would be really nice to see a storm similiar the 2003 Presidents Day storm.This effected Ohio eastward.

AJ said...

Could this change enough to put at least 5 inches of snow in Valparaiso Indiana? I really hope it can.

Gundeep said...

How much will Toronto get, It looks like we could get a good amount!

Anonymous said...

Is the storm on Christmas eve still on the radar scope?

Anonymous said...

I agree with annonymous about being confident with this storm.It is way too early to even try to call this storm. The weather changes constantly.As for the maps with the snowfall predictions,mother nature does not go by boundaries.

Mike Paulocsak said...

Hello Andrew.Looks like were going to get another soaker in Ohio.They predict an inch by thursday.Hopefully this happens in January when it's colder.

Andrew said...

AJ: We cannot tell what the models will do.

Anonymous #1: We have skimmed by it, it does look like the storm is still possible.

Anonymous #2: We use models and snowfall predictions to get a general handle on things this far out. We are not saying this WILL DEFINITELY happen- far from it, in fact. We have acknowledged that this will change, as I am no stranger to drastic model changes and mistakes.

To all: Let's clear things up here. It does seem that, in the excitement of a big snowstorm finally affecting the region we are thinking will get the worst weather, we did raise the confidence level too high. However, if you are a more avid weather enthusiast, it is a more unusual event to see such a similar set up at 168 hours out involving 51 members in an ensemble- theoretically, that is 51 chances for the model itself to be disproved.

AJ said...

Thank you for this information. I was a little to cycad about this because it could be the first winter storm. I think I asked too many questions.

Andrew said...

Even with me, winter storms can get overly exciting, which is likely why i raised the confidence level too high. Don't worry, we snow lovers go through the excitement phase quite often this time of year, especially with the snow drought ;)

AJ said...

When I tell people the weather I usually get overly exited and tell them that there is a big 90 percent chance of winter storms instead of a 40.I love winter storms and tornadoes.

Anonymous said...

Could this storm track more to the southeast?

Andrew said...

AJ: You and me both. ;)

Anonymous: At this point in time, it is certainly possible.

rod mclane said...

BIG STORM COULD TRACK MORE N-WEST ALSO??? COULD THIS STORM PHASE?? EXPLAIN IF YOU COULD WHAT THAT MEANS -(THE DAVENPORT WEATHER SERVICE HAD THAT IN THERE DISCUSSION) PHASING COULD MAKE IT MUCH STRONGER???

AJ said...

I don't see any snow in the forecast for Chicago anymore.Will this still happen?

AJ said...

Only you, weatherbug,and national weather service are saying this happen in chicago now.What are your opinions?

Anonymous said...

European shifts big time. Way different from yesterday. And it will change several more times. That's why long term confidence is a bad idea.

Andrew said...

You all must not be looking at the ensembles, which actually do have a better say than the models. The 0z ECMWF ensembles did nudge north, but not on the scale of what the actual ECMWF did. This is not a run-to-run storm, we are looking for trends.

AJ said...

So what you are saying is that this storm will probably not prompt a winter storm warning for Chicago,IL and it didn't move south into Northwest Indiana.Just about the usual.

Andrew said...

I'm not saying that at all.
I'm saying that the models have a lot of time to fluctuate, and they are. If the NWS Chicago office is right, NW Indiana should get hit, because they are predicting no East Coast ridge, which pumped the ECMWF up north in the first place.

Anonymous said...

Could extreem northwest Indiana such as Lake/Porter counties get a winter storm warning?I can not tell much with your models page down.

Mike Paulocsak said...

Hello Amdrew.What are your thought about some winterstorms in Ohio this coming January? I understand this is FAR out.But the local meteorologists are predicting some pretty HUGE winterstorms will hit Ohio east through the northeast and mid-atlantic states.In you personal opinion,do you see a major pattern change that could cause this.Like the jet stream buckling and stearing the storms properly to cause this.This is bound to happen sometime hopefully.

Anonymous said...

It looks like this storm will pretty much spare the midwest and central plains!! In fact,it looks like it is going to track away from this area.Just a thought.

Andrew said...

Anonymous #1: The NWS decides what the criteria is for a Winter Storm Warning. Criteria levels are different for each storm.

Mike: Too far out to tell.

Anonymous #2: We are over 5 days away from the event. There's no reason to throw in the towel at this stage.

AJ said...

Will you issue another discussion about this?If so,when?

Anonymous said...

could NC get hit with this storm or any storm in the next couple weeks?

Anonymous said...

could NC get hit with this storm or any storm in the next couple weeks?