Soggy September: Minnesota's record wet bias continues

Wettest 'water year' on record

New water year. Same story.

Minnesota’s record wet bias continues as we move into October. No matter how you slice the numbers Minnesota is having the wettest year on record. And it’s part of a longer-term trend of wetter years in Minnesota.

Here are some records we’re setting.

1) Wettest “water year” on record in Minnesota

Hydrologists use Oct. 1-Sept. 30 as the “water year.” That’s because precipitation that falls in autumn generally doesn’t evaporate before the following summer. It either soaks into soils or runs off.

The water year just ended is the wettest on record for the Twin Cities.

The 41.39 inches of precipitation recorded is more than 10 inches above the running 30-year average annual precipitation of 30.61 inches. For comparison, 42 inches of precipitation annually is about average for St. Louis.

2) 2019 is the wettest year to date so far

MPR climate guru Dr. Mark Seeley sends this tidbit today.

The 9-months of 2019 so far the statewide average precipitation is 29.16 inches surpassing 1986 28.73 inches, as the wettest first 9-months of the year.

3) September was the second wettest on record statewide

Again, from Seeley.

Now that we have concluded September, the preliminary rainfall statistics show 2nd highest in history on a statewide basis with an average of 6.20 inches across the Minnesota landscape, only September of 2010 with a statewide average of 6.41 inches was higher.

Wet bias continues

More rain is on the radar and on the forecast models. A stalled frontal boundary to our south continues to be the focus of heavy rainfall into Wednesday.

The stalled front is basically the dividing line between the last summery air mass to the south and the colder fall air mass to the north.

I can’t remember seeing a flash flood watch as long as the current zone. It runs from New Mexico all the way to Michigan. Wow.

Flash flood watch
Flash flood watch
National Oceanic and Atmospheric Administration

October reality check

Talk about a seasonal reality check. Temperatures are running 30 to 40 degrees colder across Minnesota today compared with Monday.

Get used to it. Highs in the 50s will be common into the weekend. Temperatures will moderate back into the (upper?) 60s by late next week.

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

We’ll probably hit 70 again in the Twin Cities this fall, but right now I don't see any more 80s in sight.

Stay tuned.

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