Arctic Saturday, growing odds of plowable snow Sunday

Wintry weekend

This weekend reminds us we live in Minnesota, and it's still February.

Saturday is likely the coldest morning for the rest of the winter. Sunday brings snow and wintry travel conditions to most of Minnesota.

Sunday snowfall

I've been talking about a Sunday snowfall all week, and that still looks to be on track. As warmer air begins to overrun the departing cold dome Saturday night, snow will break out in western Minnesota and quickly spread east. Snow should arrive in the metro after midnight Saturday night and continue through at least Sunday morning.

The latest forecast trends? A slight northeast shift in the zone of heavier snowfall from the Minnesota River toward the Twin Cities metro on Sunday.

I'm not completely sold on the (above) notion of 6" snowfall potential in the metro just yet, but this system will have to be watched closely to see just where the heaviest snow bands set up Sunday morning. I still think the heaviest bands could set up just south and west of MSP. Sunday's snowfall will have a high snow-water ratio. A 15:1 or 20:1 snow to water ratio means we could pile up several inches of dry powdery snow quickly in some areas.

Here's a look at NOAA's SREF plumes, a cluster of models and the snowfall range for the metro Sunday. The mean for all models is 5" at MSP.

Here's NOAA's SREF probability for where1" or more of snow will fall Saturday night and Sunday. The takeaway here, the best chance for the heavy snow band still lays out just southwest of the Twin Cities metro. Willmar, Mankato, Rochester could lie near the heaviest snow axis, and see the best chance of picking up some 3" to 6"+ totals.

The bottom line on Sunday snowfall:

• Expect snow to spread from west to east across Minnesota Saturday night.

• Snow should arrive in the Twin Cities metro after midnight Saturday night.

• Snow continues through midday Sunday.

• My early read on snowfall totals favors a 2" to 5" metro range by Sunday evening.

• Lower totals are likely northeast of the metro, heavier southwest.

• Snowfall totals of 3" to 6"+ are likely south and west of the metro, including Willmar, Hutch, Redwood Falls, Gaylord, Manakto, Waseca, Owatonna, Albert Lea and Rochester areas.

• There is a potential for some higher end snowfall totals in the heaviest snow bands, especially if the storm slows down.

Cold first

We bottomed out at -14 at MSP Airport on January 17th. I don't see us getting quite that cold Saturday morning. I still think -8 to -10 is a good number in the inner metro core around 7 am Saturday. The colder suburbs like Blaine and Lakeville should have no problem reaching -10 to -15 early Saturday.

Up north temps plummet into the -25 to -35 range. I won't be shocked if Embarrass, Cook, Orr and Cotton come close to -40 early Saturday. The deep blue footprint of this Arctic outbreak extends pretty far south. The zero-degree isotherm runs close to a Omaha-Des Moines-Chicago line early Saturday.

Magic disappearing dry snowfall last night

Talk about Arctic fluff. Did you notice how quickly last night's snowfall disappeared today? I've never seen a 90:1 snow to water ratio snowfall event.

60 degrees warmer next week?

To say next week looks warmer may be classic Minnesota understatement.

Temperatures recover quickly into the 30s early next week. I still see a much bigger gush of mild Pacific air arriving late next week. Here's a look at NOAA's GFS upper air 500 millibar hemispheric chart for next Thursday evening. A major surge of warmth from the eastern Pacific into the U.S. The jet stream in Canada is at least 500 miles north of it's climatoligcal mean for mid-February.

The latest Euro model runs are off the charts warm, 51 degrees next Friday with 40s next weekend? That may be too extreme, but you get the idea. We're probably going to be melting some serious snow by late next week. I hope these numbers are wrong for the American Birkebeiner next weekend.

Early spring?

If NOAA's longer range forecast trends are right, this may end up as one of the shortest winters on record in Minnesota and for the Upper Midwest. The daily runs from NOAA's Climate Forecast System (CFSv2) has been rock solid in cranking out temperatures 7 degrees warmer than average across a big chunk of North America for the month of March.

Daffodils, lilac buds and and green grass in March again this year like 2012?

Stay tuned.

From the twitter-verse

Here are some stories that caught my eye from the twitter-verse this week.

Little Great Lakes ice

Great Lakes ice cover is a good barometer for winter severity. Right now just 12.2% of the Great Lakes is sporting ice cover.

Gravity waves discovery

Einstein was right. Gravity waves are real. This is actually a huge discovery that may have weather forecast implications down the road. A "Gravity Wave Warning" coming to an NWS office near you in the future?

Supreme Court and Clean Power?

Of all the optimistic signs on climate progress, this is not one.

Super El Nino breaking the mold

It turns out El Ninos are like snowflakes. No two are exactly alike. This event is a departure from previous events in precipitation patterns.

Ice Sheets: An unknown unknown

What keeps climate scientists up at night? We don't yet know enough about just how quickly the cryosphere responds to climate change.

Winter rain increasing

Minnesota has had a 3-fold increase in winter rain and ice in the past 30 years. The Twin Cities is a "top-5" city when it come to the increase in winter rain events.

We're not alone. The strongest warming signal is in winter, and that means more precip is falling as rain vs. snow across most of the U.S.

Another way to visualize our changing winter precipitation patterns.

A Novel Idea?