Mild temps; winter storm report card

The Twin Cities office of the National Weather Service has been releasing self assessment reports for snow events this season.

The NWS forecast assessment for Monday's storm states:

 This storm was forecasted well overall. Models were consistent for almost a week with developing a major winter storm over the central Plains and tracking it east northeast to the Great Lakes.

The forecast called for significant snowfall accumulations across southern and portions of eastern Minnesota and western Wisconsin for several days leading up to the event. It was clear there would be a sharp snowfall gradient.

What made the forecast difficult was determining where it would set up. Slight run to run differences in modelling resulted in the gradient shifting north and south of the Twin Cities metro area. This decreased forecasters' confidence in its placement and prevented a depiction of a more realistic snowfall gradient in forecast graphics.

However, it was stressed repeatedly through social media and official forecast products the placement of the gradient was the highest forecast uncertainty, and that drastic changes to the forecast may occur on local scales if it shifted one way or the other.

Winter Storm Watches remained posted for the area near the gradient, while Winter Storm Warnings and Blizzard Warnings were issued earlier for the heart of the snow band. This messaging was well received by our customers. The storm moved in a bit slower than expected and a few points were deducted for timing.

The tabs on the assessment page reveal interesting details of the forecast report card.

Areas shaded yellow in this graphic indicate locations where it snowed 6 inches or more, although the forecast was for less than 6 inches:

Green shaded areas (most of the map) received their predicted 6 inches-plus snow totals.

You can see the 6-inches or more snowfalls on the northwestern edge of the storm only spread beyond the predicted coverage area by six to nine miles in the northwestern part of the seven county Twin Cities metro area.

The unusual shape of the area analyzed is due to the fact that the Twin Cities NWS forecast office has responsibility for forecasts in the shaded counties, and not for southeastern Minnesota.

There's also a detailed summary of the storm, which includes specific snow amounts.

Monday's snowstorm gave the Twin Cities it's highest official snowfall since February 2011:

We're now only 6.1 inches below our average Twin Cities snowfall total for this point in our snow season.

Snow lovers are very happy!

Fog and patches of freezing drizzle

Areas of dense fog were reported in western Minnesota this Thursday morning.

A dense fog advisory has been extended until 2 p.m. this Thursday afternoon for southwestern Minnesota:

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-

098-NEZ014-SDZ040-055-056-062-066-067-070-071-252000-

/O.EXT.KFSD.FG.Y.0002.000000T0000Z-180125T2000Z/

Lyon IA-Osceola-Dickinson-Sioux-O`Brien-Clay IA-Plymouth-Cherokee-

Buena Vista-Woodbury-Ida-Lincoln MN-Lyon MN-Murray-Cottonwood-

Nobles-Jackson-Pipestone-Rock-Dakota-Brookings-Lake-Moody-

Minnehaha-Turner-Lincoln SD-Clay SD-Union-

855 AM CST Thu Jan 25 2018

...DENSE FOG ADVISORY NOW IN EFFECT UNTIL 2 PM CST THIS

AFTERNOON...

* VISIBILITY...Visibilities will be reduced to a quarter mile or

less at times through the early afternoon.

* IMPACTS...In addition to the dense fog reducing visibilities,

fog forming on relatively cold surfaces can make roads and

sidewalks slippery.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Dense Fog Advisory means visibilities will frequently be

reduced to less than one quarter mile. If driving...slow down...

use your headlights...and leave plenty of distance ahead of you.

A dense fog advisory continues to 10 a.m. this Thursday in Minnesota counties bordering the Red River, from Moorhead down to Ortonville.

Patchy freezing drizzle is causing some slick roads in the northeast:

Special Weather Statement

National Weather Service Duluth MN

830 AM CST Thu Jan 25 2018

MNZ010-018-025-026-033>038-WIZ001-006>009-251630-

Koochiching-North Itasca-North Cass-South Itasca-South Cass-

Crow Wing-Northern Aitkin-South Aitkin-Carlton/South St. Louis-

Pine-Douglas-Burnett-Washburn-Sawyer-Price-

Including the cities of International Falls, Bigfork, Walker,

Grand Rapids, Pine River, Brainerd, Hill City, Aitkin, Duluth,

Pine City, Hinckley, Superior, Grantsburg, Spooner, Hayward,

and Phillips

830 AM CST Thu Jan 25 2018

...PATCHY FREEZING DRIZZLE THIS MORNING...

Patchy freezing drizzle, along with areas of fog, covers the

Northland this morning and will continue. According to MNDOT and

WisDOT, roads have become slippery due to minor ice accumulations,

especially the Duluth, Cloquet and Superior areas. If you travel

this morning, allow plenty of distance between vehicles, and be

prepared for variable visibilities due to the fog.

$$

WMMNZ011-012-019>021-WIZ002>004-251630-

North St. Louis-Northern Cook/Northern Lake-Central St. Louis-

Southern Lake/North Shore-Southern Cook/North Shore-Bayfield-

Ashland-Iron-

Including the cities of Ely, Isabella, Hibbing, Two Harbors,

Silver Bay, Grand Marais, Washburn, Bayfield, Ashland, and Hurley

824 AM CST Thu Jan 25 2018

...PATCHY FREEZING DRIZZLE THIS MORNING...

Patchy freezing drizzle is affecting the Northland this morning

and should some diminishment later this morning. According to

MNDOT and WisDOT, roads have become slippery due to minor ice

accumulations, especially along Highway 61 along the north shore

and Highway 53 from Duluth to the Iron Range, and east and south

of Superior on Highway 2 and 53. If you travel this morning,

allow plenty of distance between vehicles.

Elsewhere in Minnesota there could be occasional mist or patchy freezing drizzle at times, mainly this Thursday morning.

Temperature trends

Highs are expected to creep into the 30s over most of Minnesota Thursday afternoon.

Friday's highs will probably reach the 40s in the south:

Saturday will feature 30s south, with cooler highs in the north:

Twin Cities metro area highs are expected to be around 20 degrees on Sunday, upper teens Monday, then back to the lower 30s on Tuesday and Wednesday.

Our average Twin Cities high temp is 25 degrees during the last week of January.

Snow chance north

Northern Minnesota will have the best chance of snow showers on Friday and Saturday.

Southern Minnesota could see a stray snow shower Saturday afternoon or evening.

The National Oceanic and Atmospheric Administration's North American Mesoscale forecast model shows the potential snow pattern Friday through Saturday:

The color chart to the right of the loop refers to the strength of the signal that returns to the radar, not to the amount of snow.

Programming note

You can hear my live weather updates on Minnesota Public Radio at 7:49 a.m. Thursdays and Fridays, and at 7:35 a.m., 9:35 a.m. and 4:35 p.m. each Saturday and Sunday.