Saturday, September 24, 2011

1st Official 2011-2012 Winter Forecast


See the video briefing here:  http://www.youtube.com/watch?v=XA092WIrVUA
Mentioned by 8NewsWeather in Richmond, Virginia

See updated Midwest Snowfall Map Here: ***UPDATED*** 2011-2012 Winter Snowfall Map for Midwest
See the Official 2011-2012 Winter Storm Track Map and Discussion Here:  NEW: ***OFFICIAL 2011-2012 Winter Storm Track***


Hello everyone, this is the first official 2011-2012 Winter Forecast produced by The Weather Centre. We have decided that this will be an official forecast rather than a 3rd preliminary forecast, as we are investing a higher amount of confidence in this forecast than we would in a preliminary forecast.
Let's take a look at the newly-declared La Nina this year.
The La Nina is currently East-Based, meaning the lowest temperatures are sourced from the eastern regions of the ENSO areas. To know where the ENSO area is, just look along that horizontal line in the images above- that is within all the Nino regions. Anyways, looking at the SST (Sea surface temperatures), it is very clear a La Nina is in effect on the far eastern side of the ENSO region, with anomalies below -.5 degrees, which is the threshold for a La Nina. The CPC does expect this La Nina to continue and strengthen onwards as we continue through this year.
You might be wondering what all this talk about East Based La Nina is. Below are the temperature effects from West and East Based La Ninas.
The East-Based Nina favors a cooler nation, while West Based La Ninas typically torch the East Coast westwards through into the Plains. Right now, I am expecting this East Based La Nina either to stay where it is, or more likely, spread slightly westward into the center of the ENSO area.
The CPC does make forecasts as well, and they are something we analyzed closely while looking at this forecast. Below is the December-January-February (DJF) forecast for precipitation, then temperatures.

One thing to base anomalies off of is historical information from past Nina's. Below is the raw data for a typical La Nina in terms of temperature and precipitation.



Something else we can forecast for is the NAO, or North Atlantic Oscillation index.
The NAO is basically associated with a permanent low pressure system over Iceland (Icelandic Low) and permanent high pressure system over the Azores (Azores High). These two vary in daily and monthly etc. strengths, and that variation is called the NAO. Below you can see an example of the variations in pressure.

 When the pressure difference (because high pressure has higher pressure and low pressure has lower pressure) is strong, that is a +NAO index. When that difference is lower, that period is called a -NAO index. Below is a graph depicting past NAO index readings.
You can see how the NAO went negative during practically the whole 2010-2011 winter. Recently, the NAO has also been down. When the NAO is negative, it leads to heat waves across the US. You can take a more short-range past look at the NAO below.

All that considered, we can produce a very good forecast for the US. We present to you the 2011-2012 Winter Forecast by The Weather Centre.


 The Ice Threat for this year is in similar areas as to last year, but with a more pronounced threat out west with the potential for a warm winter start across the nation's midsection.

We strongly believe the North US will be very cold, with much of the north half of the US cooler than normal as well. This La Nina will keep the Southern US warm, and, yes, dry. Things will only get worse throughout this winter for the South. The entire Midwest/Northeast/Upper Midwest will get in on above average precipitation. While we cannot pinpoint if all of that will be snow, we are taking the chance that the majority will be snow. The West Coast may have to deal with another wet winter, but we are not entirely sure on that prospect. Portions of the western North Plains will have potential for above average snowfall forecast. This is based on the prospect for clippers this year. We anticipate the North Plains to receive quite a bit of snowfall from these clippers. If the worst case scenario pans out, you will need a new (and bigger) snowblower this winter in the North Plains. Lake Michigan is warm. You know what that means- lake effect snow. Undoubtedly, there will be very heavy amounts of lake effect snow for Michigan, Indiana, and probably Chicago, IL. 
There is something we have to discuss- the Southeast Ridge (SE Ridge). The SE Ridge is an area of high pressure that forms over the Southeast. This ridge of high pressure directs low pressure systems northward towards the Ohio Valley and Great Lakes/Midwest region, in turn giving those places snow. An example of this is the 2011 Feb. 1-3 Groundhog Day Blizzard. This unusually strong storm fired from the South US north and demolished Chicago and places nearby. There is a consensus that this SE Ridge will be stronger than last winter. This would mean the storms having a slightly higher likelihood of going north than south. I do see a potential for 12'' snowfalls (notice the plural) across the Midwest/Ohio Valley/Great Lakes, but I hesitantly say no to another Groundhog Day Blizzard. That was a once in over 20 years storm for the Midwest. This SE Ridge's strength may affect the Northeast's traditional 'Nor Easters', but there will still be the heavy snow, ice and rain for them too. 
Bottom line- this winter will be wild across the Northern tier of the United States. From Chicago to New York, it will get messy. If you haven't already, buy an extra shovel or two for this winter, ESPECIALLY if you live in a lake effect snow-prone area.

26 comments:

Anonymous said...

A very interesting and informative discussion, thank you! Need I mention, also very depressing unless you are an 8-year-old boy hoping for your school to close. Pass me the Prozac!

The Menace said...

and what about Utah, Colorado, New Mexico for the skiers? You left out and entire section of the country

The Weather Centre said...

My apologies- the mountains will likely be snowy once again, but the threat of huge snows like last year has decreased by at least a bit.

Mor Electric Heating said...

A very well done forecast and another brutal forecast as everybody's has been (except CFC's) so far. Buy snow shovels and heaters. Insulate.

LAC700 said...

Thank you very much- your commentary and evaluation is really above and beyond many of the independent forecast sites available. I would like to inquire a tad more about SoCal... Loved all our extra rain last year, and many enthusiasts are hopeful we will see a repeat of something at least close to that. What do you think about our precipitation- both rainfall and snow in the mountains? I notice the slightly above average colour on the map, but do you have a guess as to how that will break out for us?

The Weather Centre said...

Well, since it's a La Nina, you can expect at least some similarity to last year. However, we will have to wait and see when a specific cycle sets up that determines this winter's weather. I will issue an update mid October on this cycle, called the LRC.

Anthony said...

Amazing. looks like Maryland will be having a cold and VERY snowy winter. Like we did in the winter of 2009-2010. This year, it might be a bigger one.

I CAN HARDLY WAIT!!!!! :)

waltersg said...

kind of confused you say the south will be dry yet your chart shows the piedmont of NC (Charlotte area) as snowy with normal precip.? Please clarify this. Thanks.

The Weather Centre said...

Temperatures will be cooler across that area if it turns out as expected, and if regular La Nina precip conditions take hold, I would not be surprised to see some snowier conditions off of Nor'Easters.

Anonymous said...

Living in St. Louis, we always seem to be tettering between snow fall and ice storms. Do you think it will be the same this year?

The Weather Centre said...

Unfortunately, yes for some points. I do believe your area will get in on at least a slight majority of snow over rain. The threat of ice storms still looms, though.

gswag said...

What about skiers in southwest of california. Last year there was a lot of high pressure trophs that melted/rained on our slopes so what I as an owner of a ski resort expect in respect to snowfall/ tempuratures?

Anonymous said...

Hello.What are your thoughts on heavy snowfall for Ohio.I'm located in Holmes county Ohio.I'm not talking about LAKE EFFECT snows.I'm talking about storms coming up the Ohio valley through Pittsburgh Pa.

Andrew said...

gswag- I do anticipate the West Coast to be wet once again this year as storms will make landfall to eventually go cross country into the Eastern half of the US.

Anonymous-We do believe some storms will be coming up through the Ohio Valley, bringing rain and snow in some cases. However, agreeing with the CPC's interpretation of a very wet winter in the Ohio Valley region, it looks like your area will be in for a wild winter.

You can both check our Final 2011-2012 Winter Forecast and see what our final thoughts will be for this winter on November 5th at 12:00 PM CDT.

Anonymous said...

Hello Andrew.Thanks folr answering my question.I'm the Anonymous who lives in Holmes county Ohio.I have another question.What are your thoughts on the al,anacs forecasts?They put Ohio in the mild and dry zone this upcoming winter.I totally disagree,what about you?I considerr myself a WINTER MANIAC.I love studying winter storms.Also,do you think that Ohio will get any severe ice storms versus snow storms?I'm in Holmes county Ohio.Thanks.

Andrew said...

Anonymous- I am completely against that, hands down. In fact, are you confident you are looking at this year's almanac? Anyhow, the La Nina currently in place, combined with an active storm track and colder winter completely defies the Farmer's Almanac.

Mike Paulocsak said...

Hello Andrew.Thanks for answering my question.I saw this in the old farmer's almanac 2011-2012 edition.This is anonymous,my name is actually mike.IO also disagree with them completely.I even emailed them personally telling them they didn't have a clue what they were talking about.They said I was wrong,go figure.

Andrew said...

Mike- The deal with the Farmer's Almanac is absurd. For what it's worth, our upcoming final winter forecast actually (spoiler alert) features the opposite for the Ohio Valley.
I just brought this up with my fellow weather enthusiasts and I will get back to you soon on what they have to say.

Mike Paulocsak said...

Hello Andrew.Absurd is what I thought too!! I'll be wating for you to get back with me.I'm hoping I get alot of snow this winter.

Andrew said...

We didn't get too much response, but the response that we DID get was in agreement that the Farmer's Almanac is incorrect in how it forecasts.

Mike Paulocsak said...

Hello Andrew.So your saying basically,ignore the almanacs.I never did trust them.I'll be looking out for your updated winter forecast this Saturday.

breanne said...

When do you think the snow will start in st.louis. Do you think it will start in November?

Andrew said...

Due to the pattern we are in, probably not. As soon as we break out of this complicated pattern, we should see winter start up in Mid-December.

Anonymous said...

Can you please tell whether it'll snow in Richmond, Viriginia this winter. It is already end of Jan, but still no snow. It is also very warm for this time of the year. My kids are waiting to see snow. Please reply.....

Andrew said...

Anonymous: We will be releasing a new FEB-MAR outlook tomorrow at 12:00 PM CST.

Anonymous said...

Thanks for replying. Will be waiting to see the new Feb-Mar outlook....