2/9/09: Storm Update Number 1

Issued at 2:18 AM CST, Monday, February 9th, 2009

*Ice Storm Warning* for Duluth in effect from 9 AM CST Monday until 12 PM CST Tuesday.

Storm Prediction Center in Norman Oklahoma has a risk for General Thunderstorms up to Duluth for Today and Tonight with a 5% risk for thunderstorms to become severe and produce large hail across Southern and the Southeast half of Minnesota.

Low pressure at 08z was centered over Northeast Colorado with a pressure of 997 mb. Strong 2 hour pressure falls of 3 mb extended out into Nebraska and Western-Northern Kansas early This Morning.

Early Morning water vapor satellite imagery shows a potent H5 trough lifting north-northeast out of the Rockies and toward the Western High Plains…12 hour 500 mb height falls of 120 meters were occurring from Western Nebraska down to West Texas and Eastern New Mexico.

Current radar imagery shows a large area of freezing rain and rain lifting north-northeast through Northwest and Westcentral Minnesota. Radar echoes are also developing over Northern, Central, and Eastern Minnesota…But, none of this precipitation was making it to the surface at the moment.

Surface temperature at 2 AM was 25 degrees at the Duluth Airport and 27 degrees Downtown. Dewpoints were in the upper teens with winds just beginning to turn to the southeast. Surface temps along the North Shore of Lake Superior have fallen into the mid and upper teens early This Morning with dewpoints generally in the low teens.

Looking at the new model guidance from late Tonight reveals that the low will deepen as expected with it tracking from Western and Central Nebraska toward Northeast South Dakota by Tonight, then toward Northwest Minnesota on Tuesday. Appears there may have been a slight shift toward the east with the surface low track come Tuesday, but it’s not by very much.

Still appears that the bulk of the heavier precipitation here in Duluth will occur This Afternoon through late This Evening with freezing rain and or rain being the precipitation type. East winds will also be on the increase Today and Tonight with wind speeds of 15 to 25 mph expected. Precipitation totals by Tuesday could reach 0.25″-0.50″ in Duluth, and if the majority of this falls as freezing rain…Then, will likely see some power outages and trees coming down in the city. One thing i’m a little leary about is the fact that since this storm is becoming negatively tilted, alot of our precipitation will likely come up from Eastern Minnesota or even Western Wisconsin…Problem is that the models really don’t show much precipitation occurring over those areas during this event… The heavier amounts of precip seem to be confined to Westcentral and Northcentral into Northeast Minnesota…Mainly west and north of Duluth per model data. So whether this verifies or not remains to be seen, but it’s definately something to keep a watchful eye on, as these precip totals could end up being a lot less if a few of the forecast models work out.

Surface temperatures will play a critical role in determining whether or not the rain freezes or not. I’m pretty confident that areas along and over the hill in Duluth will see quite a bit of ice from this storm, but areas down below the hill are more uncertain.

More updates forthcoming.

Tim

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