Waves of soaking rain and thunder

Umbrellas and duck boots.

Our well-advertised low pressure storm is here. Waves of rain and some embedded thunder sweep across Minnesota through Wednesday as the low deepens and moves northeast.

The National Oceanic and Atmospheric Administration's Rapid Refresh model paints the waves of rainfall sliding across Minnesota overnight into Thursday morning.

Expect wet conditions and some thunder overnight, and a wet morning commute Wednesday. Wipers on medium to high at times?

• Current Twin Cities radar loop

Soaking rains

The rain swath squeezes out some local, soaking downpours at times. Models still vary on totals, but I can easily see widespread half-inch to 1 inch totals across a big chunk of Minnesota.

Here's NOAA's North American Mesoscale Forecast System 4 km resolution rainfall output through noon Wednesday.

The Twin Cities National Weather Service office lays out the system and rainfall totals nicely.

• 64 degrees high temperature at Minneapolis-St. Paul International Airport Tuesday

• + 16 degrees vs. average

More typical March cold front ahead

This week's weather brings something that's been rare lately. A cold front with air that's actually colder than average.

The average high by Thursday is 49 degrees in the Twin Cities. We'll fall short of that number later this week. Nights below freezing are more typical for late March than what we're used to lately.

'True spring' in sight?

Late winter felt like spring in Minnesota. But early season warmth comes with a shaky promise of seasonal staying power. We've been in seasonal limbo, the next cold snap always a potential model run away.

The upper air pattern looks much more favorable for sustained spring like warmth starting late next week. Westerly wind flow brings milder air in April. The jet stream lifts north into Canada.

NOAA's Climate Prediction Center sees the coming trend, and paints an area of approaching warmth by next week as Pacific air invades form the west.

NOAA's Global Forecast System model is locking onto the trends. I see a more consistent run of days in the 60s ( maybe 70?) and nights above freezing by late next week.

True spring my be just a week or so away.

Arctic Sea ice reaches another record low

And the warm weather hits juts keep on comin'.

News from NOAA that Arctic Sea ice coverage is once again at record low levels.

Another record low for Arctic sea ice maximum winter extent

Arctic sea ice appears to have reached its annual maximum extent on March 24, and is now the lowest maximum in the satellite record, replacing last year’s record low. This year’s maximum extent occurred later than average. A late season surge in ice growth is still possible. NSIDC will post a detailed analysis of the 2015 to 2016 winter sea ice conditions in early April.

On March 24, 2016, Arctic sea ice likely reached its maximum extent for the year, at 14.52 million square kilometers (5.607 million square miles). This year’s maximum ice extent was the lowest in the satellite record, with below-average ice conditions everywhere except in the Labrador Sea, Baffin Bay, and Hudson Bay. The maximum extent is 1.12 million square kilometers (431,000 square miles) below the 1981 to 2010 average of 15.64 million square kilometers (6.04 million square miles) and 13,000 square kilometers (5,000 square miles) below the previous lowest maximum that occurred last year. This year’s maximum occurred twelve days later than the 1981 to 2010 average date of March 12. The date of the maximum has varied considerably over the years, occurring as early as February 24 in 1996 and as late as April 2 in 2010.

Below average sea ice extent is in part a result of higher than average temperatures that have plagued the Arctic all winter. Air temperatures at the 925 hPa level from December 2015 through February 2016 were above average everywhere in the Arctic, with hotspots near the Pole and from the Kara Sea towards Svalbard exceeding 6 Celsius degrees (11 degrees Fahrenheit) above average. These higher than average temperatures continued into March, with air temperatures during the first two weeks reaching 6 degrees Celsius (11 degrees Fahrenheit) above average in a region stretching across the North Pole toward northern Greenland, and up to 12 degrees Celsius (22 degrees Fahrenheit) above average north of Svalbard.

These unusually warm conditions have no doubt played a role in the record low ice extent this winter. Another contributing factor has been a predominance of southerly winds in the Kara and Barents seas that have helped to keep the ice edge northward of its typical position. This area has also seen an influx of warm Atlantic waters from the Norwegian Sea.