Arctic into Saturday, February thaw next week

Ups and downs. Ebbs and flows. Strikes and gutters.

There's often little rhythm to Minnesota's erratic weather patterns. Unusually wide and sudden swings are the trademark of weather at 45 degrees north in the middle of a huge continent. If you want rhythm and predictability try Tucson, Ariz., or San Diego.

Minnesota's weather marches to the beat of a different weather drummer. Weather volatility here can make stock markets look reasonably tame.

In the next week we enjoy all that an erratic El Nino-fueled Minnesota winter has to offer. Squeaky cold. Fluffy snow. A wintry mix, more February rain and the prospect of 40 degree temperatures.

Job security for meteorologists. Conversation fodder for the checkout aisle at your local Cub.

• 13 degrees high at Minneapolis-St. Paul International Airport Wednesday (3:53 p.m.)

• 3 degrees low at MSP Wednesday (7:50 am..)

• -11 degrees vs. average Wednesday

• 3 degrees  temps vs. average so far in February

One more arctic push

The next arctic high pressure blob pushes south Friday on the maps. On the last frame you can see the number 1,046 near the big blue H as it dives south. That's 1,046 millibars of central pressure for the high.

As meteorologists in the Upper Midwest we take notice of inbound high pressure cells in winter reaching 1,040 millibars or higher. That's respectable for an incoming Arctic air mass. Another patch of blue brings a snowy dusting to southwest Minnesota Thursday evening. "Train 1046" follows with sub-zero air by Saturday morning.

Watch the southerly surge of sub-zero temperatures on NOAA's North American Mesoscale Forecast System 4 km resolution model by late Friday night.

We bottom out Saturday morning. I think minus 8 is probably a good number for the inner metro core, with 10 below zero or colder in the suburbs. The traditionally colder nooks and crannies of northeast Minnesota bottom out between minus 25 and minus 40 Saturday morning.

Sunday snow chances

By late Saturday night warmer air begins to overrun the cold dome as it departs Minnesota. That will spark a widespread area of light snow. Snow spreads east Saturday night and lingers through much of Sunday.

This doesn't look like a huge snow producer, but I can easily see a couple of inches and slick roads across most of Minnesota late Saturday night and Sunday.

NOAA's NAM model captures the essence of the advancing snow shield by late Saturday night.

February thaw next week

The snow marks the leading edge of a milder Pacific air mass as it blows into Minnesota next week. Several days in the 30s are looking more likely, and the odd of thermometers topping 40 degrees again late next week is growing. Here's a more detailed look ta the next week and the transition from Arctic air to a Pacific thaw.

A few highlights from the weather twitter-verse 

Check out this impressive high resolution loop of lake-effect snow bands over Lake Superior. The parallel snow bands can contain convective elements with thunder snow, and are sometimes called "cloud-streets."

Guatemala volcano erupts.

True color loop of cyclonic vortex near Australia. Yes, storms really do spin the other way in the southern hemisphere.