A very cool Sunday, with periods of rain

Chanhassen NWS radar offline for 3 weeks starting on Monday; several rounds of showers and thunderstorms this week

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This probably isn’t the kind of weather that you’d order up for your September Sunday. We’ll have cool temperatures, with periods of rain in many locations.

Rain update

Roughly the southern third of Minnesota, plus parts of west-central/southwestern Wisconsin can expect periods of rain as we go through Sunday. Occasional scattered showers are possible from central Minnesota into northwestern Wisconsin. Southern Minnesota could also see an isolated afternoon thunderstorm. The Twin Cities metro area will ride the northern edge of the main rain swath. I wouldn’t be surprised if the far south metro sees many more minutes of rain this Sunday than the far north metro.

As always, updated weather information can be heard on the Minnesota Public Radio Network, and you’ll also see updated weather info on the MPR News live weather blog. You can see the recent local NWS radar loop here. The northwestern Minnesota radar loop and the northeastern Minnesota radar loop are also available. The recent radar loop for southwestern Minnesota can be found here, and the southeastern Minnesota loop here.

A batch of showers and thunderstorms is expected to move through Minnesota and western Wisconsin Monday and Monday night. The National Oceanic and Atmospheric Administration's North American Mesoscale forecast model shows the potential rain pattern Monday and Monday evening:

NOAA NAM simulated radar Monday through Monday evening

It’ll rain in some areas that look dry in the loop, but the loop illustrates the general rain pattern. An isolated thunderstorm will also be possible.

The National Weather Service Storm Prediction Center shows a marginal risk of severe weather Monday and Monday night for much of southern Minnesota:

Severe weather outlook for Monday and Monday night
NWS Storm Prediction Center

Marginal risk means that an isolated severe thunderstorm is possible. The severe weather outlook for Monday will be updated Sunday afternoon and early on Monday.

There’ll be additional rounds of showers and thunderstorms Wednesday and Thursday. Many parts of Minnesota and western Wisconsin could see 2 to 4 inch rain totals from today through late Thursday.

Temperature trends

Sunday highs will be mainly in the lower 60s across Minnesota and much of western Wisconsin, with some upper 50s where the the thickest clouds and the rain linger a bit longer. A few spots in far northern Minnesota could see highs in the mid 60s.

Highs in the 70s return to far southern Minnesota on Monday;

Monday forecast highs
National Weather Service

Some spots in the Twin Cities metro area will probably reach 70 degrees. Our average high temp is 75 degrees in the metro area this time of year.

Tuesday highs will range from the 60s in far northern Minnesota to the lower 80s in the far southeastern corner of Minnesota:

Tuesday forecast highs
National Weather Service

Some spots in the metro area could touch 80 degrees Tuesday afternoon.

Metro area highs are projected to reach the mid 70s Wednesday and thursday, then dip back into the 60s on Friday.

Starting on Monday, the Twin Cities NWS doppler radar will be offline for 3 weeks

There’s never a real good time to take a radar offline, but it has to be done periodically to keep the equipment functional.

Duluth NWS radar was taken out of service for several days in August for a major upgrade. Now it’s time to upgrade the Twin Cities NWS doppler radar in Chanhassen:

Here are some details about the radar upgrade::

Twin Cities National Weather Service

According to the National Weather Service:

This is one of four major upgrades, known as service life extension projects (SLEP), planned to replace and refurbish major components of the 20+ year old WSR-88Ds and to keep the radars operational into the 2030s.

The NWS explained how storms will be monitored while the NWS doppler radar in Chanhassen is out of service:

During the outage, radar coverage is available from adjacent radar sites including Duluth, MN; La Crosse, WI; Des Moines, IA; Sioux Falls, SD; Aberdeen, SD; Grand Forks, ND; and the Minneapolis Terminal Doppler Weather Radar (TMSP TDWR).

Are you curious about what’s involved in the upgrade? Here’s a time-lapse of the pedestal replacement that was done to the NWS radar in Pendleton, Oregon:

Programming note

You can hear my live weather updates on Minnesota Public Radio at 7:49 a.m. Thursdays and Fridays, and at 7:35 a.m., 9:35 a.m. and 4:35 p.m. each Saturday and Sunday.