Summery weekend heat; Severe storm threats for Sunday and Monday

Temperatures have warmed well above normal across western, central and southern Minnesota on Saturday to kick off Memorial Day Weekend. Parts of southern Minnesota including Mankato, New Ulm, Waseca, Owatonna, St. James and Tracy reached the low 90s Saturday afternoon.

Dew points are up as well as southern moisture blows in.

Meanwhile, much chillier temperatures persist in northeastern Minnesota, courtesy of Lake Superior. Grand Marais reported just 47 degrees at 5 p.m.

With the chilly air and moisture from the big lake, a dense fog advisory has been posted until 1 p.m. Sunday for the North Shore as well as Carlton and southern St. Louis Counties in Minnesota and South Shore areas of northwestern Wisconsin.

Heat continues Sunday and Monday for much of Minnesota

High temperatures on Sunday should be mainly in the 80s for central and southern Minnesota with some spots probably touching 90 again. Most of northern Minnesota should see 70s while there will be cooler 60s for some in the northeast. The Twin Cities should have a high in the mid 80s.

Monday will be hot across eastern and southern Minnesota. The Twin Cities should have a high around 88. But northwestern Minnesota will feel a cooler breeze from Canada as a cooldown reaches our doorstep.

Severe threats through Monday

A messy, complex weather system will create three periods of potential severe weather for Minnesota before the end of Memorial Day Weekend:

·         Saturday night into Sunday morning

·         Sunday evening and well into Sunday night

·         Monday afternoon and evening

Campers and boaters are generally unprotected and should stay especially weather aware this weekend.

Saturday night into Sunday morning

Scattered thunderstorms will develop across western Minnesota after midnight Saturday night and track northeast toward northern Minnesota. Most storms will not be severe, but there is a marginal risk (level 1 out of 5) for severe weather mainly in western Minnesota for the period ending at 7 a.m. on Sunday. Isolated severe storms are possible. Wind and hail will be the risks.

Sunday evening and Sunday night

A more dangerous wave of storms is likely later on Sunday. Strong storms will develop over western Minnesota Sunday afternoon and reach eastern Minnesota Sunday evening and overnight. The Storm Prediction Center has issued and enhanced risk (level 3 of 5) for part of western Minnesota and as far east as the western metro areas for the 24 hours ending at 7 a.m. on Monday. Numerous severe thunderstorms are possible. All forms of severe weather are possible, but wind and hail will be the most likely for eastern Minnesota including the Twin Cities. The tornado risk should be mainly along the western edge of the state.

Monday afternoon and evening

Monday is the day that concerns me the most. A deepening low pressure center will build toward hot, moist air over Minnesota. Periods of strong thunderstorms are likely in the afternoon and evening. An enhanced risk (level 3) has been posted for that time period from Crookston to Fergus Falls to the western metro and down to Mankato and Albert Lea. Numerous severe thunderstorms are possible with risks of very large hail greater than two inches and damaging winds in excess of 75 mph. Tornadoes are likely.

More rain possible Tuesday

Yep, more rain might arrive on Tuesday, but it won’t be severe. What it might do, however, is add unwanted water to soggy parts of northern Minnesota. Forecasts indicate that northwestern Minnesota could pick up two to three inches of rain, and maybe more in spots, by 7 p.m. on Tuesday.

Cooler beginning on Tuesday.

Cooler air will continue to replace the hot, sticky stuff on Tuesday. Wednesday will be cool but pleasant.