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Monthly Archives: December 2012

Hey everyone!

I hope you all had a wonderful holiday with your families and friends, whether it be celebrating Christmas or Hannakuh, being with those you love is most important.

I had a wonderful Christmas and I’ll be bringing an update on the storm affecting the Midwest and now the East Coast tonight when I get back to Bloomington, Indiana.

Until then

Meteorologist Mack

P.S. Bloomington, Indiana happened to see 12.5″ of snow yesterday. I would bet that is a record for most snowfall in one calendar day, but I will do some research for you and let you know in my post this evening.

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Snowfall Totals So Far:

Des Moines, IA: 12.4″

Dubuque, IA: 12.1″

Hartford, WI: 13.0″

Beaver Dam, WI: 14.5″

Middleton, WI: 18.5″

Verona, WI: 16.0″

Some very impressive snowfall totals out there. Also, very strong winds have been seen with this storm. Many places have seen wind gusts between 40 and 55 mph.

Stay safe out there and stay off the roads unless you must travel.

Until next time

Meteorologist Mack

(By the way, it started snowing in Bloomington, IN around 4pm EDT. Very exciting!)

**Winter Storm Forecast Discussion**

December 19, 2012

Last week, it was Winter Storm Caesar, which paralyzed Central Minnesota and the Twin Cities Metropolitan Area. This week, we have yet another large, dynamic winter storm taking aim on regions to the south, including Nebraska, Iowa, Kansas, Wisconsin, and Michigan. Blizzard Warnings, Winter Storm Warnings, and Winter Weather Advisories have been posted for these states as this storm begins to take shape.

Regional radar currently shows a large area of snow centered over Nebraska, and Iowa, with rain being reported to the south in eastern Kansas and Missouri. The surface low, as of 7:00PM EDT, is centered over extreme south-central Kansas, with a pressure of 997mb. This low is forecast to strengthen to 988mb and deepen as it lifts to the east northeast overnight, tracking through Chicago by early Thursday evening. This system is well supported in the upper levels, with a strong, 500mb trough, going from a neutral tilt, to a more negative tilt as it lives east northeast Thursday. Aided by a strong jet streak of 100 knots and a closed low of 528dm at 500mb. Additionally, this storm will be aided by strong warm air advection and deep moisture transport from the Gulf of Mexico, wrapping into the storm. Visible satellite imagery depicts a large, baroclinic leaf setup with this storm, which indicates the presence of this strong jet at 500mb. This is often the initial stage of a developing low pressure system. Overnight, the system will begin to form along this boundary and what was once a wave of low pressure, will strengthen into a powerful winter storm over the Great Lakes region. With a negative tilt trough, both cold air advection and WAA will further strengthen, as the storm continues to deepen as it moves through Chicago Thursday evening.

By the time this system makes its way through Chicago, blizzard conditions will be seen through much of Iowa and Wisconsin. Very heavy snowfall will be seen in areas such as La Crosse, Wisconsin Dells, and Ames. The dynamics of this storm are impressive, as snow is being generated, not through colder air moving in behind this storm, but through the strength of the warm air being ingested into the storm. As this warm air rises, we see pressure falls in response, and the column of air cools to the north of the low, causing rain to change over to heavy, wet snow. Additionally, this storm has a great deal of moisture to work with, setting the stage for very heavy, wet snow. Precipitable water values (the depth of water in a column of the atmosphere if all the water in that column were precipitated as rain. As a depth, the precipitable water is measured in inches) are high with this storm, between 0.75 and 1.25 inches. This will lead to widespread snowfall totals of 6-18″ with isolated amounts of up to 2 feet, where heavier snow bands set up. In the heaviest snow bands, thundersnow is possible, with rates of 2-3″ per hour likely. Strong winds, gusting to 45-55 mph will be seen to the northwest of the low and north, causing whiteout conditions. This is a life-threatening storm and all precautions need to be taken to protect life and property.

With regard to the safety of life and property, it is very important that you have a winter preparedness kit in your car, in case you get stranded. I would advise not to travel unless it is absolutely necessary. Road conditions will quickly deteriorate and travel would be unwise. It is best to hunker down and ride this storm out. This storm is very similar to the Blizzard of 2011 in Chicago, that paralyzed the region for days. Thundersnow occurred with that storm as well, as parts of Chicago and Milwaukee saw upwards of 30″ inches of snow. This storm won’t produce quite as much snow, but the winds will be just as strong, creating very dangerous conditions.

I will bring updates on this storm as it continues to develop tomorrow, and until then, stay safe and hunker down for this one.

Meteorologist Mack

Hello Everyone,

What a difference a day can make. On Monday, we saw record highs all across the eastern two-thirds of the nation, with over 400 record highs in December set. On Tuesday, temperatures began to fall as the month of December decided to actually make itself known. On a related note, the nation hasn’t seen much snow to start the month and we are well below normal in terms of snow cover. However, that is all about to change this weekend, as a large storm develops in SE Colorado in response to upper level forcing in place, as a large trough digs out in the western United States. With moisture in place, and the Gulf of Mexico open for business, this storm will likely be the precursor to future storms for mid to late December.

For the most part, we have seen a very mild November and early December, but temperatures will return to normal/below normal for mid-December after this storm moves through this weekend. An arctic cold front will dive south and eastward, bringing with it much colder air that has been trapped up in Canada for weeks. With this pattern change, the storm track, which has been predominantly to the north in Canada over the past month, will drop further south, bringing more unsettled weather to the eastern two thirds of the nation. In fact, much of the central plains states have been dealing with an exceptional drought, and hopefully, a more active with pattern will bring much needed precipitation to the region. The image below can give you an idea of just how dry it has been.

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The one thing that sticks out is the lack of drought seen in southwestern Texas as compared to last year at this time. Unfortunately, where one place receives rain, another place often doesn’t and that looks to be the case over much of the front range and central plains. If only the central US could pick up the type of rainfall that the west coast has been seeing. We’ll have to wait and see, but as the 6-10 day precipitation outlook shows, the central part of the US won’t be seeing much in the way of serious precipitation until late next week.

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Now, I realize I may have drifted off topic slightly, so, here’s a look at the forecast for the snowfall. Right now, it looks as if much of the snowfall will remain north of the Interstate 80 line. Much of the Dakota’s, Minnesota, Wisconsin, and Michigan will see the bulk of this snow from this storm, however, on Monday, if temperatures are able to cool enough into northern Illinois and Indiana. The first measureable snowfall of the season is on tap for the Minneapolis Metro, and Chicago could even see a couple of inches by the time all is said and done. In fact, according to long time Chicago Weatherman, Tom Skilling, Chicago is on track for a record longest period without measurable snowfall. It would tie the record (280 days) on Sunday, and perhaps break the record (281 days) on Monday. However, it is possible that Chicago could see measurable snowfall on Sunday, but the most likely chance of measurable snow would be more likely on Monday.

The following graphic depicts the probability of seeing snowfall with this upcoming system, both Sunday night and Monday. The heaviest snows will likely fall in North Dakota and central and north central Minnesota on Sunday. I believe these areas will see about 4-8” of snow by Monday. Minneapolis should see around 3-7” of snow, with places in the northern metro seeing the totals on the higher end.

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Those colder temperatures will follow the arctic cold front, bringing an end to the mild weather we have been seeing so far in December. I’ll bring a few updates on the storm as it evolves tomorrow and Saturday.

Until next time,

Meteorologist Mack