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2/7/09: Winter Storm Watch

Issued at 5 PM CST, Saturday, February 7th, 2009

*Winter Storm Watch* now in effect from Monday Morning through Tuesday Morning for Northern Minnesota…Northeast Minnesota…And a small part of Northwest Wisconsin.

Counties in the Duluth area included in this watch are:

Koochiching MN… Itasca MN… Cass MN… Crow Wing MN… Aitkin MN… Carlton MN… Pine MN… St. Louis MN… Lake MN… Cook MN… And Douglas WI…

Some cities in the Duluth area included in this watch are:

International Falls MN… Grand Rapids MN… Walker MN… Brainerd MN… Aitkin MN… Moose Lake MN… Cloquet MN… Esko MN… Duluth MN… Cotton MN… Hibbing MN… Virginia MN… Two Harbors MN… Silver Bay MN… Lutsen MN… Isabella MN… Grand Marais MN… Superior WI… And Solon Springs WI…

A deepening area of low pressure is forecast to lift north-northeast from the Western High Plain states reaching Eastern North Dakota or Northwest Minnesota by Tuesday Morning…Freezing rain and sleet will spread into the watch area on Monday with freezing rain, sleet, or rain continuing through Monday Night and Tuesday Morning.

The potential exists for ice accumulations to reach or exceed one quarter inch in the watch area by Tuesday Morning.

This much ice accumulating on trees and power lines could lead to power outages and cause trees to come down.

In addition to the icing threat, rain that falls will run-off due to frozen grounds which could lead to areas of flooding around the area.

Specifically for the Twin Ports:

Precipitation should start as freezing rain or sleet on Monday with the heaviest round of precipitation expected to occur Monday Night…By that time, temperatures may warm enough to cause mostly rain to fall, but winds coming off Lake Superior could keep surface temperatures in the 30-32 degree range…Even if surface temperatures rise a degree or two above freezing and causes rain to fall Monday Night, it’s still possible that this rain could freeze on tree limbs and power lines and on any colder surfaces. The greatest potential for ice accumulations to cause damage will probably end up occurring over the hill in Duluth, and for areas along the Higher Terrain near Lake Superior.

It’s going to be an interesting storm to watch early next week and many factors will determine whether or not we see a damaging ice storm…Or just minor icing, followed by rain here in the city. The temperature profile of the atmosphere looks warm with H85 temps rising to +2 to +4 degrees C in the city Monday through early Tuesday, meanwhile most of Lake Superior has ice over it…So winds coming off those ice covered waters could keep surface temps from getting above the freezing mark… I would still rather see the high set-up over Ontario versus Eastern Canada like in this set-up…We would have a much better chance to keep the cold air in place if that high was to our north, but with the high being to our east in this event, low level winds out of the southeast could cause enough warming in the city to prevent much icing. Also will have to watch the whole evaporative cooling aspect since the dewpoints will likely start out pretty low in this event, but forecast models are consistent in showing dews climbing into at least the low 30s in the city by Monday Night. So, it appears likely that any precip that comes down in the city on Monday would be frozen…But, by Monday Night the precipitation could be ice or rain.

Stay tuned

Tim

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