Posted at 8:37 AM on December 22, 2009
by Paul Huttner
Twin Cities NWS weather story paints areas of ice and heavy snow.
The Christmas Mega Storm of 2009 is not ready to pull the trigger just yet, but it's definitely taking aim. Here are some current rends with storm thinking as new model runs come in.
-The big picture remains the same. Expect snow, ice, winds and poor travel conditions in the entire Upper Midwest from Wednesday evening into Saturday. The storm will get going earlier in Iowa and Nebraska, where travel may be difficult as early as this evening.
-The latest model runs jog the storm center slightly more to the west on Christmas Eve. This may suck in enough warm air to briefly change snow over to ice as far west as the Twin Cities Christmas Eve, before changing back to all snow. It may also mean a significant ice storm is possible from Eau Claire to Rochester and La Crosse and much of eastern Iowa.
-The "sweet spot" for heaviest snow appears to be from the west metro to Willmar, to Mankato south to the Iowa border near Worthington. These are the areas most likely to see snowfall totals of one foot or more.
-It appears snowfall will spread north from Iowa Wednesday morning, and the first waves of snow may approach the metro late Wednesday afternoon into early evening.
-The heaviest part of the storm and highest snow and ice intensities still appear to be the second half of Christmas Eve through Christmas Day.
-I still think snow totals of 12" to 18"+ are possible in the heavy snow axis by Saturday afternoon. Exactly where this axis sets up is still a little uncertain, but it is looking more like a Worthington, to Mankato to western Twin Cities' line.
The Cobb Technique is one of the methods for forecasting snowfall amounts. Check out the output for Twin Cities Airport below. The overnight model runs suggest as much as 18" for the Twin Cities. The run for Eden Prairie suggests an incredible 20+" total !
Cobb output cranks out 18" for the Twin Cities by Saturday.
We'll get two more main model runs before the storm gets cranking Wednesday evening.
Stay tuned for changes and updates.
I just moved up from Chicago in August and was looking forward to going back to see my family. Any thoughts as to when it might be safe to travel on 94 to Chicago from the metro area? Might it be clear enough Saturday?
"Expect snow, ice, winds and poor travel conditions in the entire Upper Midwest Minnesota from Wednesday evening..."
What is the "Upper Midwest Minnesota"? That sounds like the Moorhead area.
You frequently talk about computer runs that occur overnight and the frequency, or, rather infrequency, of the available output implies that these run still require significant amounts of horsepower. Is this true?
Thanks for the updates! When do you think the confidence in the models will be high enough to have a good handle on where the track of the storm will be? I don't like hearing that a more westerly track is being projected, as like some others here I have plans to drive to SE MN on Thursday. If it does stay more to the east, will we be spared the mixed precipitation in favor of all snow? Just trying to figure out if I will be able to plan ahead whether or not to brave it, or if this will be a "game time" decision.....
For some reason, that is one of the most confusing maps I have seen in a long time. The little "cloud" outlines completely obscure the state boundaries and make it quite difficult to read.
Otherwise, thanks for the updates. :)
For 35 years I've driven/flown out of state for Christmas. This year we are driving to SE Iowa to spend Christmas Eve and then, on Christmas Day, we head for Southern Indiana.
The map you have provided in this post is the best visual I've seen on this storm. We now know what we have to do.... Leave a little early.
Merry Christmas to you and yours.
April, I agree. The words "Wintry Mix" on the lower-right cloud are nearly impossible to read due to low color contrast and being overlaid with the color of the larger zone.
However, Paul's text is, as always, excellent. It's great to have a knowledgeable person giving us the meteorological overview and insight.
Minneapolis has had snow this year. There is an entire northern MN economy that would like to hear some comments about what can be expected for outstate MN even if it is not as dramatic as what the majority of Minnesota metro residents will "enjoy". I have gone on line ot other sites and am not uninformed, but one cannot do that while driving the car.
You'll be dlighted to hear tonight's model trends are expanding the heavy snow areas north. Brainerd and Duluth may end up with 15" to 20"+. One model is even cranking out an incredible 30" for Duluth!