7" of snow already in parts of the metro; 10-12" possible

The one-two winter punch that socked the Twin Cities could leave 10-12 inches of snow before moving on Tuesday, but impending spring may soften the blow.

By 6 a.m., snowfall totals of 7 inches were being reported in the metro area, according to the National Weather Service.

New Hope had 7.3 inches, and St. Louis Park had 7 inches, the weather service said. Higher totals were reported to the north of the Twin Cities area, including 8.2 inches in Monticello.

Aided by advance salting and relatively mild temperatures, road crews aimed to keep up with the snowfall by working through the night and into daylight.

"With warmer temperatures and the sun out longer during the day, this should be one of the easier events," said Todd Howard, assistant Dakota County engineer.

Nonetheless, messy road conditions prompted some school closings and late starts in outstate areas and likely will turn metro commutes into a slog.

Minneapolis street maintenance supervisor Mike Kennedy wasn't about to say whether the city would call a snow parking emergency. March, with its warming temperatures, can make that a difficult call.

Daily high temperatures are expected to climb from around freezing Tuesday to near 40 over the weekend, but nighttime lows will fall into the low teens Tuesday and Wednesday and remain below freezing through the weekend.

A pair of low-pressure centers brought the overnight snow. But instead of working like the fast-moving Alberta Clipper storms of recent weeks, the lows were bogged down, with one slowing the other down "like an anchor," said National Weather Service Twin Cities meteorologist Tony Zaleski.

Snowfall amounts across most of Minnesota on Monday were relatively modest, with 5 inches at St. James being the tops. The official Twin Cities total was 1.4 inches. Monday evening the weather service was still predicting a two-day total of 7 to 10 inches for the metro area and 8 to 12 inches for much of southeastern Minnesota. Late Monday, the National Weather Service posted a winter storm warning from northwestern Minnesota all the way southeast to Ohio.

Tuesday's expected snowfall should push the Twin Cities' seasonal snowfall above normal. Precipitation since Jan. 1 is 22 percent above normal, Zaleski noted.

"I don't think anybody was thinking we were going to be above normal as recently as two to three weeks ago," he said.

At the same time, soil temperatures below freezing may prevent much of the moisture in the snow from melting into the soils below. In much of Minnesota, particularly the southwest and northwest, a fall and early-winter drought left those soils at near historic dry levels, according to state climatologist Greg Spoden.

Across southern Minnesota, early-winter rains froze into an impermeable cap over dry soils beneath, which will most likely lock out any snowmelt.

The net result is that drought relief from the snow is unlikely in the dry regions.

Spodin said that even flooding won't alleviate a drought.

Delta Air Lines said Monday it was waiving fees for one-time changes in travel plans for passengers using the Minneapolis-St. Paul Airport and others in the Upper Midwest on Monday and Tuesday. The other airports include Bismarck, Fargo, Grand Forks, Minot,Williston, Cedar Rapids, Des Moines and Sioux Falls.

pwalsh@startribune.com • 612-673-4482