Sunday, January 29, 2012

February 2-6 Potential Significant Snowfall

The latest 18z GFS is printing out a stunning 2 feet of snow for the Great Lakes regions, with widespread 1 foot+ totals across the Northeast and Ohio Valley. This storm has been watched very closely and with this run, the need to monitor this scenario only grows.
At this point it looks like the models are projecting a low pressure system to eject out of the Plains and into the Ohio Valley, where it phases with another strong storm system, thus introducing massive amounts of snow into the Northeast and Ohio Valley.

The PNA looks to be raging positive in this timeframe, leading me to think that this scenario up to the system appearing in the Plains will happen. From then on, it gets a little dicier.
The Arctic Oscillation looks to be moderately negative in this timeframe, enhancing the potential for snow. The NAO looks to me like it may stay positive through this timeframe. The CPC NAO chart, which takes in multiple models, shows that the NAO should be anywhere from neutral to moderately positive in this timeframe. That will have to be closely watched.
A big factor will also be the MJO, forecasted to go into Phase 6 into 7, however the storm should strike in Phase 6 if this verifies. Phase 6 favors the Midwest and Ohio Valley for Precipitation, but also includes parts of the Northeast. This somewhat goes along the MJO lines.
Here's where it gets confusing. The MJO will be strong, meaning its effects will be stronger than usual. At the same time, the PNA will be a strong positive, meaning its effects will also be noticeable. This means that it can come down to these two factors. A closer analysis of the MJO reveals that the heaviest precipitation in a transition of phases 6 to 7 typically occurs in the interior Midwest and lower Great Lakes into the Ohio Valley.
What this 18z GFS has done is combine the +PNA and Phase 6 MJO in an incredible fashion. I believe that if any solution is to work with the PNA and Phase 6 MJO being the main factors, the 18z GFS is the one.

BUT THEN THERE'S MORE!

The GFS Ensembles. As I have claimed this winter, the models are horrific in performance. Thus, I have advocated the use of ensembles throughout. This 18z run is a different story in some aspects for the storm.
Hour 144 18z GFS ENS.
Hour 156 18z GFS ENS.
Hour 180 18z GFS ENS.
The GFS Ensembles have the system bring in more precipitation into the interior Midwest and Ohio Valley than the 18z GFS itself.

My Thoughts
Looking at the MJO in Phase 6, I think that this could go either way. Both the 18z GFS and 18z GFS Ensembles print out very good solutions in my opinion. However, seeing as the MJO will be in a very strong phase, it may win out the PNA to push the storm track and precipitation a tad further west like the ensembles are showing above. On the other hand, a very strong PNA could also waver the MJO to take the storm to the Northeast and keep it away from the Midwest, like the 18z GFS itself is showing.

FOR NOW, i'm going to go with the ensembles, because I feel a consensus among a group is more powerful than a consensus among one person. I emphasize 'for now' because both parties I have shown here are putting up quite good arguments.

Any questions you have may be asked below in comments.
~Andrew

19 comments:

Aran said...

Hi Andrew,any possibility Valparaiso Indiana could be in a foot of snow?Also, what is your confidence level on this system?Thank you for what you have done and I hope nobody picks on me.

Andrew said...

Aran: The exact amounts remain yet to be seen- this is a general overview. My confidence level is moderate, which I consider pretty good for a storm this far out. No one will pick on you.

Mike P. said...

Hi Andrew.I hope nobody here cuts me down again!Anyway,could this storm dump heavy snow on both eastern and northern Ohio?I'm located between both regions.Thanks.

Wally said...

Andrew as long as others are asking I'll join in. Huntley, Illinois is about 45 miles northwest of Chicago. Yoi mentioned the midwest so I assume you mean Huntley. What am I looking at ?
Wally, Huntley, Ill

Jeremy Peterson said...

I think I am going to give it a few days before I get to worked up about it.

To many let downs this season to worry to much.

We are all due though.

Am I seeing another system in the north west about the same time? I wonder how that will track. It would be nice to get a double shot.

J.

Anonymous said...

http://raleighwx.americanwx.com/models/12zlinegraphs.html

Vlad said...

That 18z run of the GFS made no sense. It was clearly showing snow for central MO as 540 line was down in boot heel and there was still quite a bit of precipitation around. I was expecting a few inches and then looked at the snow map. BAM. nothing. I just don't understand because the what the model was showing with temps and precip didn't match up at all with that snow map. Any explanation why Andrew?

Anonymous said...

What impact will this possible storm have on the mid atlantic?

eddie said...

Andrew is this becoming more possible because SOI values are dropping AO negative and NAO around nuetral and PNA positive?

THANKS

Anonymous said...

could the southeast (charlotte nc) get any snow?and if not this system will we get any this winter?

Anonymous said...

is that map correct its showing hamilton ontario in 20 - 22 inches of snow that would be awsome if its true

Alice McDonald said...

Interesting....can't wait to hear more.

Andrew said...

Mike: The 0z GFS is looking worse, so it's back to a tossup scenario. However, going on ensembles, your area would still get a lot of snow.

Wally: The GFS Ensembles have your area in a pretty good spot for snowfall.

Vlad: Were you looking at hours 120-180 for precipitation?

Anonymous: There could be some big snows per the GFS Ensembles and ECMWF ENSembles.

Eddie: Yes, as well as the GLAAM falling and the MJO moving into a strong phase 6-7.

Anonymous #2: This system may be too far north for Charlotte, but you never know.

Anonymous #3: Yes, but it changed during the 0z GFS run while the ensembles did not.

We will be updating you at 4:00 PM CST again on the storm.

Owen12789 said...

What about Springfield, IL? Will we get any snow? Right now NOAA is saying just a chance of snow. When they do this it makes me wonder what might happen. Any thoughts?

Thanks.

Tom C. said...

Hello Andrew.....What do you see happening west of the Catskill NY and east of Binghamton NY.Hoping to get the snowmobiles out.

mike paulocsak said...

Hi Andrew.All the models have a different solution to this storm.It's probably going to come down to the last hours until we can tell what it is really going to do.I'll be looking out for the update you will be posting.

Andrew said...

Owen: The chance of snow is likely out of uncertainty. You can see the forecast in our update at 4:00 PM CST this afternoon.

TOM C: I would certainly watch this system.

Mike: yes, they are confused. I have a side note you should read about the confused models at the end of the 4:00 PM CST update.

Vlad said...

Models have gotten a lot worse today. Still time. But very discouraging.

Anonymous said...

Hey Andrew. I dont mean by anyway to be a downer or anything of that nature but my local guy here in Ohio is say no snowy weather or even close to snow condition for some long time up here in Cleveland. They say nothing about this storm. Only people to say anything really has been you and accuweather. You guys seem to be the only right ones these days. Whats your thoughts on this storm ? Thanks for you time friend Justin.