Rare warm February rain system Tuesday

Get ready to witness a symptom of climate change in Minnesota on Tuesday.

Minnesota climate experts — including Mark Seeley, a retired University of Minnesota climatologist and regular MPR News contributor — have documented that the frequency of winter rain and ice storms has tripled in Minnesota in about the past 50 years.

We’re about to get a clear example of our warming winters Tuesday when a low-pressure storm tracks into Minnesota. This system is warm enough for mostly rain in the Twin Cities and southern Minnesota. It will be barely cold enough for accumulating snow in much of western, central and northern Minnesota.

Rain will develop early Tuesday morning across our region. The heaviest rain shower bursts will occur Tuesday midday through the afternoon into the early evening.

The National Oceanic and Atmospheric Administration’s Global Forecast System model (above) seems to have a fairly decent handle on the progression of the rain and snow zones between 6 a.m. Tuesday and 6 a.m. Wednesday.

Soaking February rainfall

We don’t often use the phrase “soaking rain” in February, but that’s exactly what lies ahead Tuesday for the southeast half of Minnesota. Most forecast models are cranking out at least one-half inch of rain Tuesday, with some models up to around an inch.

The European Centre for Medium-Range Weather Forecasts model lays out a widespread zone of significant precipitation through Tuesday night.

All that rain falling on moisture-rich snowpack is going to produce some huge puddles Tuesday.

Snow north and west

It will be just cold enough for significant accumulating snowfall across much of western and north-central Minnesota. Winter storm watches are out for much of western and northwestern Minnesota.

A band of 3 to 6 inches of wet snow looks likely across Minnesota from around Fargo, N.D., through Bemidji to International Falls on the Canadian border. A lesser zone of 1 to 3 sloppy inches is likely from Madison in western Minnesota through Alexandria and Brainerd, to the Iron Range cities to Ely.

In the Twin Cities rain will likely change to a little wet snow around or after midnight. Many areas may pick up to an inch of slushy snow before it ends early Wednesday morning.

Unusually warm system

Most years I would be forecasting heavy snow for most of Minnesota with this system. But temperatures Tuesday will be well above freezing across most of Minnesota, and likely in the 40s from the Twin Cities south and east.

Keep in mind, the average high and low for Feb. 14 in the Twin Cities are 28 and 12. So temperatures will be more than 10 degrees warmer than average with this system.

The rest of the week looks mainly dry and more seasonal after Tuesday’s unusually warm and wet February system.