Rainy days and Mondays; flash flood threat

The Carpenters 1971 hit pretty much sums up Monday’s forecast.

A slow moving cold front spawns numerous showers and thunderstorms Monday across Minnesota. The slow moving nature of the storms means heavy rainfall potential is there. Southwestern Minnesota is the favored zone for the flood threat. But local downpours could add up quickly in the Twin Cities too, especially late Monday afternoon and evening.

Slow moving storms

The cold front crawls slowly east from the Dakotas into Minnesota Monday. That means storms will linger and dump locally heavy rain as they edge slowly northeast Monday. The Canadian GEM model seems to have a fairly good handle on the rain zone as it moves slowly east Monday through Monday night.

Canadian GEM model from 1 pm Monday to 7 am Tuesday, via tropical tidbits

Heavy rain zone favors west-central Minnesota

The potential for flash flooding rains favors west-central Minnesota. The National Oceanic and Atmospheric Administration’s High-Resolution Rapid Refresh model paints a multi-inch rainfall swath from the western Twin Cities north and west.

The 4 inches-plus rainfall bull’s-eye west of the Brainerd Lakes area may not be precise, but it gives you the idea of how heavy some rainfall totals may be by Monday night.

Rainfall forecast, via NOAA’s HRRR model from pivotal weather

Severe risk southwest

Torrential rain, small hail, gusty winds and frequent lightning accompany the stronger storms Monday. Heavy rainfall is still the highest risk, but a couple storms could trigger severe thunderstorm warnings for damaging winds and large hail especially late this afternoon.

The Twin Cities rides the edge of the marginal (low) risk. The risk of a severe storms is slightly higher in southwestern Minnesota.


Dry front Tuesday

Tuesday’s inbound air mass is pleasantly dry. Dew points in the 40s will feel amazing. Monday’s gunky dew points in the 60s get shoved southeast to Chicago and beyond. Benefits of living close to Canadian air masses in summer.


Heat returns late this week

Our respite from heat and humidity will be brief. Tuesday and Wednesday look gorgeous. But highs will push 90 by Saturday, and dew points could hit the oppressive 70-degree mark.

NOAA forecast data, via Weather Bell

Keep the umbrella handy Monday.