Evening Update: Domebuster II? 10″ to 17″+ totals possible

Update 6:40pm:

Here's an eye opener.

The latest 18Z (noon) GFS run is cranking out an incredible 22.5" storm total snowfall at MSP Airport!

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GFS snowfall total now = 22.5"!

For the record I think that number is on the extreme high side, and the next run may (hopefully!) reduce that total. I'm sticking with a general 10" to 17" snowfall range in the metro and much of central & southern Minnesota by noon Monday posted in my more complete discussion below.

Sure makes tonight's model run a little more interesting though!

More after about 9:30 to 10pm tonight when I've had a chance to sift through the new numbers.

PH

***orignal post 2:20pm Saturday***

Here we go again.

The latest forecast models are in, and all signs still point to another major winter storm "event" for much of central & southern Minnesota...including the Twin Cities metro Sunday.

Winter storm warnings are now in effect from 6am Sunday to 6am Monday.

NWS Winter storm warnings. (Click to enlarge)

Here are the latest details on the coming winter storm, which will slam the area Sunday.

The System:

Potent low pressure is developing today in Colorado. The low will deepen and move east into Iowa Sunday. The models remain consistent on the track, which is usually a heavy snow producer for Minnesota.

Timing:

It appears that a broad area of "lift" will rapidly develop in southern Minnesota after midnight, and snowfall will bust out from SW to NE overnight. Snowfall should get going in SW Minnesota (Pipestone to Redwood Falls) by around midnight, and begin the Twin Cities sometime between 2am & 6am.

As the low moves closer Sunday, snowfall will intensify during the morning hours Sunday. It looks now like peak snowfall intensity (rates of around 1" per hour) should be between noon Sunday and midnight Monday. Snowfall should be heaviest during those 12 hours Sunday PM & evening.

Lighter snow may continue into Monday morning before the snow tapers from north to south Monday.

Snow water content:

Moisture surging up form the south means the snow will be relatively wet during the first part of the storm. The NAM model is cranking out a snow:water ratio of 7:1 early Sunday PM. The snow should dry out as the storm progresses, with snow:water ratios approaching 20:1 late Sunday night & Monday.

Snowfall totals:

The forecast models are consistent so far in laying the heaviest band of snow on a rough Ortonville-Redwood Falls-Willmar-Twin Cities-Eau Claire line. This may extend on the north end as far as St. Cloud, and as far south as Mankato to the south.

Within the heavy snow band I now expect a general area producing snowfall totals between 10" and 17" including the Twin Cities metro!

NAM model lays heaviest snow band right through Twin Cities metro.

As you can see on the map, snowfall totals will taper on the northern end toward Duluth and south into Iowa.

The NAM is cranking out a (scary!) 17" total for MSP Airport by the time the storm ends Monday. This may be on the higher range of things...but it is not out of the question that we may see similar totals to the "Domebuster" storm in December that produced 10" to 20" snowfall.

NAM: 1.25" liquid yields 17" snow total at MSP Airport!

(click to enlarge for better view)

At this point my best estimate is that most snow totals in the heavy snow band will range between 10" and 17" by Monday noon. It is possible we could see some snowfall totals in excess of 17".

Wind driven snow:

Northeast winds will build into the 15-30 mph range as the storm intensifies Sunday. This will be a wind whipped snow. Expect blowing and drifting in open areas, especially Sunday night.

Ice south:

Mild air above freezing in the lowest 5,000 feet of the atmosphere will surge into southern Minnesota briefly Sunday. This may create a wintery mix of sleet & ice in Worthington, Mankato, Albert Lea and other towns along the I-90 corridor. Expect snowfall to be reduced accordingly, but the ice will make for treacherous travel.

Thundersnow?

The upper air dynamics with this storm, and the fact that ice may move close to the southern metro at times may combine to create thundersnow in parts of southern Minnesota. Do not be surprised to hear a clap of thunder Sunday PM or evening, followed by a "burst" of heavier snow.

Bottom line & travel:

-This will be a major winter weather "event" for central and southern Minnesota Sunday into Presidents' Day.

-This could be the 2nd biggest snowfall of winter for many Minnesota locations. (MSP Airport picked up 17.4" in the Domebuster storm in December!)

-Travel should be okay tonight into the wee hours Sunday...but travel conditions will deteriorate rapidly Sunday morning. Travel will be very difficult to dangerous Sunday PM into Monday morning. You may want to get those "errands" done today and tonight!

Craig Edwards and I are watching the developing storm closely and will have extra updates tonight and Sunday as the storm ramps up on MPR news stations and here in Updraft.

We've set the table so to speak...now let's wait to see one more major model run tonight before the flakes start flying early Sunday morning. I'm still looking for a scenario that will produce less snow with this system, but right now I can't find one. Maybe tonight's model run will shed more light.

Prepare accordingly and stay tuned!

PH