Monday, March 4, 2013

-Snow event update - 4 PM.

/Issued 3:12 PM CST, Monday, March 4th, 2013/

*The map below represents where precipitation totals of at least 0.01" will occur centered on 3 AM Tomorrow Morning.  Notice the sharp gradient in NE Minnesota between red colors=90% chance of 0.01" totals to less than a 50% chance.  Another way to look at it, Duluth is on the line between a 70-90% chance, but you get up to about Two Harbors and there in a much smaller chance.  Two Harbors isn't very far from Duluth.  Difficult forecast, hey I think I've mentioned that a few times here Today.  Snow band shifts 30-50 miles either way and it will make a difference.

-Winter Storm Warnings and Advisories continue in parts of the Northland thru Tuesday.
-Heaviest snow accumulations mainly west/south of Duluth/Superior.
-Still have low confidence on just how much snow we see here in Duluth Tonight and Tomorrow.

Today's Weather Summary for Northeast Minnesota and Northwest Wisconsin

Low pressure of 1008mb was centered near Bismarck, North Dakota (Central part of the state) at 3 PM with another low of 1002mb over Eastern Kansas.  So far there hasn't been much snow in the Northland as dry air off a strong 1030mb high to our north advects into our area eating away at the snow as it moves this way.  Skies were partly sunny to mostly cloudy Today with highs in the 20s to around 30 degrees.  Winds were out of the east at 5 to 15 mph with higher gusts, especially near Lake Superior.

Today's Upper Level Analysis

A potent upper level low with 60-90 meter height falls was over the Northern Plains This Afternoon per water vapor satellite imagery.  Another H5 low was over the Northeast U.S./Eastern Canada, and this feature is part of the reason why the Northern Plains system will drop south-southeast instead of it moving more on an easterly track.  850mb temperatures as of 3 PM ranged from -6 to -10C in Minnesota.

*Watch/warning map from the Duluth National Weather Service.

Areas in pink are under winter storm warnings and purple color represents a winter weather advisory.  These headlines are in effect through Tuesday.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Short Term Forecast - Confidence:  Low to Moderate Tonight and Tomorrow.

Tonight and Tuesday (March 4th-5th)

Surface low over Central North Dakota This Afternoon will wash out as the low over Eastern Kansas becomes the primary as it tracks toward the Ohio Valley during the next 24-36 hours.  An inverted trough combined with a strong mid/upper level low will continue to move south/southeast out of the Northern Plains and into the Upper Midwest through Tuesday.

This forecast continues to be a tricky one with high bust potential.  High pressure to our north continues to feed lots of dry air down into our area (typical for this time of year) so as the snow approaches from the west-southwest it gets eaten up by the dry monster.

The computer models remain consistent in showing snow becoming more widespread in parts of our area Tonight, but this will likely be a slow process.  It still looks like will see a very sharp snowfall gradient and where that sets up is being handled differently by the various computer models even at this late hour.

I'm thinking the line between snow and no snow will setup from about International Falls to Hibbing to Two Harbors.  Locations east-northeast of this line may not get much snow at all from this event.  If you're west-south of that line, expect to see at least some snow Tonight and Tomorrow.

...Expected snowfall totals by Tuesday Afternoon...

4-8" in Western-Southern parts of our area, including the cities of International Falls, Northome, Bigfork, Grand Rapids, Cass Lake, Walker, Pine River, Brainerd, Hill City, Aitkin, McGregor, Pine City, Hinckley, Siren, Grantsburg and Siren.  Note:  The highest amounts of 6+" look like they will be over the Brainerd Lakes to Lake Mille Lacs to Hinckley-Pine City areas.

3-6" for Floodwood, Duluth and Superior, Cloquet, Moose Lake and Solon Springs, south to Minong, Spooner and Shell Lake.  Note:  The bust potential is high for the Twin Ports.

1-4" for the Iron Range as well as the North Shore from Silver Bay to Two Harbors, this also includes Northwest Wisconsin from Port Wing to Bayfield to Ashland, south through the Hayward Lakes.

Low temperatures Tonight will be in the teens and 20s with highs Tomorrow mainly in the 20s.  Winds will be out of the east or north at 10 to 20 mph with higher gusts near Lake Superior.  Areas of blowing snow are possible Tonight and Tomorrow, especially around the head of Lake Superior.

Tuesday Night

Partly to mostly cloudy skies are expected with lingering flurries possible.  Lows will be in the single digits to around 20 degrees with northerly winds at 5 to 15 mph.

*Latest winter weather graphic from the HPC valid through Tuesday Afternoon.

Red=High risk for at least 4" of snow.
Green=Moderate risk for at least 4" of snow.
Blue=Slight risk for at least 4" of snow.

*15z SREF snowfall accumulation forecast for Tonight and Tomorrow.  The legend is on the left hand side.

Extended Forecast - Confidence:  Medium.

Wednesday through Friday (March 6th-8th)

Wednesday looks fine with dry conditions and highs in the 20s with lows in the single digits.  Could see some light snow or mixed precip for Thursday and Friday as low pressure approaches from the west.  Warms up a bit later this week with highs in the 20s and 30s.  Lows Thursday Night will mainly be in the teens.

Long Range Forecast - Confidence:  Medium.

(March 9th-14th)

The period to keep an eye on looks to be from the 10th-12th this is when a storm over the Southwestern U.S. could move into the Central U.S. and possibly the Great Lakes.  This looks like a fairly mild system, however, so if it does affect us it could bring rain or a mix of rain/snow to the Northland late this weekend and early next week.  Temperatures are forecast to be near seasonal averages during this period.


Timing:  Until 6 PM CST Tuesday.

.Tonight...  Breezy.  Occasional light snow or flurries possible before Midnight, snow accumulations less than 1".  Occasional snow after Midnight with 1-2" of accumulation possible by 6 AM.  Mostly cloudy.  Low 17 to 22.  Wind east to northeast at 10 to 20 mph with gusts to 30 mph near Lake Superior.  Some blowing and drifting snow is possible Overnight.

.Tuesday...  Snow with accumulations of 1-4" possible.  Total snowfall accumulations of 2-6".  Mostly cloudy.  High 22 to 27.  Wind northeast at 10 to 20 mph.

.Tuesday Night...  Flurries possible.  Partly to mostly cloudy.  Low 5 to 10.  Wind north at 10 to 15 mph.

.Wednesday...  Partly cloudy.  High 25 to 30.

.Wednesday Night...  Partly cloudy.  Low 5 to 10.

.Thursday...  Mostly cloudy.  High 30 to 35.

.Thursday Night...  Mostly cloudy.  Low 15 to 20.

.Friday...  Mostly cloudy.  High 30 to 35.

Normal temperatures for Today

High:  30
Low:  13

Sunrise Tuesday:  6:40 AM CST
Sunset Tuesday:   6:01 PM CST