Another (snowy) near miss; Winter’s report card so far; Why is some ice still unsafe?

Near miss as snowstorm clips southeast Minnesota today

2/3 of meteorological winter in the books after tomorrow January 31st

Highly variable ice thickness still in late January on parts of Lake Minnetonka and other Minnesota lakes

48 hour Arctic Outbreak rolls into Minnesota through Friday

22.5 days of sub-zero minimum temps on average each winter at MSP

6 days of sub-zero lows in the metro so far this winter season

2 more days of sub-zero lows tomorrow & Friday morning

1-2 more days with sub-zero lows likely the rest of this winter?

Another "near miss" for the metro:

Snow is flying today in Iowa, southeast Minnesota and Wisconsin. It's another tantalizingly close call for southern Minnesota snow lovers...after a good dumping up north yesterday.

4" to 5" is already on the ground near Des Moines and Waterloo, and a swath of 6"+ snowfall will decorate a path from near Des Moines to central Wisconsin by tonight.

Tough driving? Yes. But that snowfall is liquid gold for winter sports, and the water content in the snow will help boost rivers & lakes in the coming weeks.

Winter's Report Card: Milder with near average precipitation so far

So far this winter season is going about as I expected when I walked out on the weather limb with my winter outlook in November.

Image: Tim Nelson - MPR News

Here's where we stand at MSP with 2/3 of "meteorological winter" (Dec-Feb) in the books after tomorrow.

Temps:

December +3.7F

January +1.9F (estimated finish after cold outbreak)

Overall +2.8F vs. average so far

Comments: December was relatively mild with just one day reaching the zero mark, on Christmas morning.

January has been much closer to "real winter" in Minnesota this year. At just +1.9F vs. average, temps ran relatively close to average this month. The 5-day sub-zero arctic outbreak from January 20-24th strung together 5 consecutive sub-zero lows at MSP Airport for the 1st time in 2 years... since Jan 19-23rd, 2011.

The likely total of 8 sub-zero days with temps at or below zero this month is close to the 30-year average of 9.5 days for the month of January.

My read at this point is we'll likely see 1-2 more nights of sub-zero lows in the Twin Cities in February. That would put us at around 10 for the winter season.

Snowfall:

Heavy snowfall at the Weather Lab on December 9th

Image: Paul Huttner - MPR News

20.4" so far

33.3" average season snowfall to date

-12.9" vs. average to date

+5.5" vs. last winter to date

Comments: The big story so far this winter was the 10.5" snowfall on December 9th.

Image: Twin Cities NWS

The heavy snow cover did a quick disappearing act with snow cover down to 1" by the 16th after temps reached the 40s on December 11th & 12th. Nearly half an inch of rain fell on the 15th, wiping out most of the residual snow cover.

Snowfall is running ahead of last winter's pace so far, but still below both the 30-year and longer term average.

Overall precipitation since December 1st: 2.50"

Average precipitation since December 1st: 2.01"

Surplus precipitation since December 1st: +.49"

It is somewhat surprising that overall precipitation is running above average so far this meteorological winter. That can be attributed to rainfall events, which have become 4 times more common in winter the past few decades.

Looking ahead: February to close "meteorological winter" on a mild note?

Trends for the next 2 weeks suggest milder than average weather for the Upper Midwest. That would likely bring February in warmer than average, and guarantee a milder than average winter overall.

Image: NOAA/CPC

There are some signals that favor increased precip...snow and rain in February. Let's hope so...we'll need every bit of moisture to help recharge river & lake levels this spring.

Right now drought is the big story going into the spring of 2013. We'll need much above average rainfall once the ground thaws out to replenish parched soils.

Ice still not safe everywhere:

This has been a crazy winter for ice safety. Ice thickness is highly variable this winter. There's 16" to 24" in some bays...with open water just a few hundred yards away.

We know ice is never "totally safe"...that there are always thin spots where water flows through channels etc. This winter has seen more open water than any I can remember with this much cold air around.

A dozen vehicles...and some iceboats have gone through the ice near the Weather Lab in Lake Minnetonka in the past two weeks.

The channels are still open water, and a huge pressure ridge west of the Minnetonka yacht Club in the "main" Lower Lake continues to produce open water in late January.

This car found it.

Image: M. Martin via Lake Minnetonka Patch

One theory is that there was so much extra heat content stored deep in the lake water this past summer...that it's been tough to get a good solid freeze this winter. Bouts of sustained cold have been tough to come by...punctuated by thaws.

No matter the causes, make sure you know where you're going and the local ice thickness if you venture out on your favorite frozen lake this winter.

PH