Saturday, November 10, 2012

Major Thanksgiving Storm Likely For Midwest, Great Lakes

I am making the call for a major Thanksgiving storm system (likely with snow) to hit the Midwest, Great Lakes, and possibly the Plains and Northeast. Let's take a look at why I am now making this call.

This is a 500mb height anomaly forecast, valid a few days out. As you can see, there isn't much going on in the United States, so why am I showing you this? Well, we have to go to East Asia for that answer. If you look in the top left corner of the image, you will see a strong trough present in East Asia. It has been shown that there is a 6-10 day gap between what happens in East Asia and what happens in the East US. So, if we use this forecast (valid November 13) and apply the 6-10 day gap to it, we end up at November 22, or a day or two from Turkey Day.

We can also use the Lezak Recurring Cycle (LRC), which is, in the simplest of simple explanations, a repeating pattern that forms every fall and cycles through the winter. This pattern first forms in September-October. A strong storm system hit the Plains, Midwest and Great Lakes on October 2. If we use the expected 51 day gap between each cycle and add on a day or two to give the forecast a little wiggle room, we find this strong storm system hitting the Midwest/Great Lakes on November 21-23, which falls right on Thanksgiving!

I think it's time we turn to the models to see what they're saying. This is the morning forecast from the GFS model for Thanksgiving. This image shows precipitation over a 12 hour period, as well as MSLP lines. The pink line is the rain/snow line. Any precipitation above that line would be snow, and precip. below the line is likely to be rain. The GFS is forecasting a pretty strong storm system to be present across the Midwest/Great Lakes on the morning of Turkey Day. While the GFS has been juggling the position of this storm system, it has been forecasting a strong storm system in the general East US on Thanksgiving.

As you can see in the above forecast, there is a lot of color above the pink line. Yes, this would mean snow. However, because all I am confident in is the presence of a storm in the mentioned regions, I don't think now is the appropriate time to make calls on precipitation. However, if there is to be precipitation, it will most likely focus in on the Upper Midwest and Great Lakes.

This is likely to be the most accurate forecast for this system if we rely on the LRC, but any East US forecast with a strong storm system could verify if we use only the East Asian theory. Personally, I think it's a good idea to combine the two and use the GFS forecast above (which will definitely change in coming days).

Let's sum this all up:
•I am making a call for a storm system on Thanksgiving Day.
•This system will hit the Midwest, Great Lakes, and Northeast.
•Snow is likely, possibly heavy in some areas.
•Cold weather will follow the system.

Andrew

15 comments:

Aran Jacobs said...

I hope your forecast is right!!

Aran Jacobs said...

Where are you getting you models?I have looked all over the internet and haven't found the models you are using in this forecast.

Anonymous said...

He got the first image from:
www.meteo.psu.edu/~fxg1/ewall.html

He got the second image from:
www.wxcaster.com/models_main.htm

Andrew said...

Comments are deleted if they are not related to the weather or are offensive to viewers.

Anna said...

Hey when r u updating the snow radar? Randy raised a good point.

Andrew said...

Aran: Anonymous is correct.

Anna: Recent events have led to the deterioration of the Snow Radar. I will post a poll momentarily on the right sidebar concerning the future of the Snow Radar.

Aran Jacobs said...

Thank you

Anonymous said...

I'm hoping this plays out as you say it will. Where I live, snow is somewhat rare even on Christmas, so a potential winter storm on Thanksgiving would be an event to remember.

dillon said...

so andrew, u said anything above the pink line is snow? i noticed to snow line wayyy down south. does this mean kentucky has a chance of some snow?
im just excited this winter because last winter all we saw was 1.9 inches the entire year..THNXS!

mike paulocsak said...

I hope this verifies as a snowstorm,not a rain event.Temps. will be the crucial factor to who gets rain and who gets snow.This looks very interesting!

mike paulocsak said...

Hello Andrew.I understand why you went back to saving the comments for site approval.It's too bad we have to have people on here that don't know how to post decent comments.People can just be mean I guess.Anyway,it would be nice if this storm did come to pass,and bring many snowfall.

Teddyz1919 said...

Looks like a strong NE wind off Lake Michigan for the Milwaukee area!!! Perfect for lake enhanced snowstorm!! Hope it holds true!!

Joshua Steiner said...

Hey Andrew.. You do know that Turkey Day is on the 22nd right? Just sayin'

Other than that an EXCELLENT forecast. I agree completely. I don't want to explain my reasoning here.. But I will if you want.

Anonymous said...

What about memphis,tn?

Anonymous said...

Are you still seeing this? Not a weather forecaster is seeing this at all! I am somewhat baffled!

bree