June-tember: Summer warmth and flood risk return

2 to 5 inches of rainfall possible by Friday

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Here we go again.

The calendar says September. The weather maps are stuck in perpetual June. Summer warmth and downpours spill into meteorological autumn this week.

Monday’s rains were just the appetizer for a soggy smorgasbord Wednesday and Thursday. The potential for heavy rainfall works north across Minnesota this week.

Excessive rainfall outlook
Excessive rainfall outlook
Twin Cities National Weather Service

Summer returns Tuesday

September sun heats up a warm, humid air mass to summer levels. It’ll feel more like July out there Tuesday afternoon.

Your local National Weather Service Office thermometer flashes 80 degrees in southern Minnesota and the Twin Cities Tuesday. September-like temperatures in the 60s linger across northern Minnesota north of the warm front.

NOAA high temperature forecast today
High temperature forecast today
National Oceanic and Atmospheric Administration

Another multi-inch rain event

The air mass over Minnesota and the Upper Midwest is unusually soggy for mid-September. Dew points in the 60s and even 70s are more typical of mid-summer. That extra moisture is fuel for heavy downpours. Low-pressure waves work through late tonight through Thursday.

The National Oceanic and Atmospheric Administration’s NAM 3 km resolution model paints multiple waves of rain and thunder across Minnesota starting after midnight through Thursday.

NOAA NAM 3 km resolution model
NOAA NAM 3 km resolution model Tuesday night through midday Thursday
NOAA, via tropical tidbits

Flood risk

Several inches of rain will fall across a good chunk of Minnesota by Friday. Many of us will pick up another 2 to 4 inches. That’s a month’s worth of rain again this week, folks.

Rainfall potential this week
Rainfall potential this week
Twin Cities National Weather Service

The Canadian model is especially aggressive with heavy rain potential with local totals in excess of 5 inches close to the Twin Cities.

Canadian model rainfall output this week
Canadian model rainfall output this week
Environment Canada, via tropical tidbits

June weekend ahead

This upcoming weekend will feel more like late June. Highs in the 80s linger into next week. Some models suggest highs between 85 and 90 degrees for the Twin Cities and southern Minnesota next Monday and Tuesday.

NOAA temperature forecast for Minneapolis
Temperature forecast for Minneapolis
NOAA, via Weather Bell

Right now, I don’t see any real sign of true fall until at least the last week of September.

Stay tuned.