A Goldilocks Spring So Far - But Don't Let Your Guard Down With River Flooding

Paul Douglas
April 02, 2020 - 8:35 am
winter
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Ah, spring. If you squint, tilt your head and use your imagination it (almost) looks like spring out there at times. Ice is coming off area lakes, those piles of dirty snow that looked so formidable a few weeks ago are downright puny now, and the Twin Cities has picked up just over 4 hours of additional daylight since December 21!

Spring is always two steps forward, one step back, and this week is no exception. The metro area will see rain showers, while close to 10" of heavy, wet, cement-like snow plasters the Red River Valley by Friday. Thoughts and prayers for friends in Crookston and Grand Forks, where Old Man Winter will be holed up for a couple of days. Any heavy snow may heighten and extend the river flood threat for the Red River Valley.

Flood Area

River Flooding Updates. NOAA's North Central River Forecast Center has updates on flood stages. As of April 2 flooding was observed on the Red River.

A gradual thaw, coupled with few substantial snow and rainstorms in March has allowed snow to melt at a moderate pace, lowering the risk of spring flooding somewhat, but we are not out of the woods just yet, according to Twin Cities National Weather Service Meteorologist in Charge, Dan Luna: "It's way too early to say we are out of the woods. For the southern part of MN, it was an "ideal" snow melt that produced minor to moderate flooding in some locations.  The Red River and the upper Mississippi are just getting started and we will see moderate to major flood levels in the Red and moderate flood levels on the Mississippi from St. Paul downstream. Any additional significant precipitation could push other locations to major flood levels throughout the state" Luna explained during an interview yesterday. If you've experienced flooding problems in past years you may still see sudden rises in the weeks to come.

If past history is any indicator, April will bring not only river flooding, but the first strong to severe thunderstorms, the first puff of noticeable humidity and the first 70s by the end of the month. The last few Aprils have brought significant late-season snows, and more slush certainly can't be ruled out. But the pattern this year is significantly different than the last couple of springs. The odds of big snow events is lower, but not zero. Don't retire heavy jackets and shovels yet. You'd just be inviting a winter storm.

Snowfall Winter

Winter Snowfall. After a promising start for snow-lovers significant storms detoured south of Minnesota for much of February and March. Source: NOAA and Praedictix.

snowfall departure

Snowfall Departure From Normal. Much of Wisconsin and roughly the northern half of Minnesota has picked up more snow than average so far this winter. Source: NOAA and Praedictix.

 

Winter snowfall, to date, is 44" in the Twin Cities. During an average winter (last 30 years of data) about 54" of snow falls in the Twin Cities. We could still make up for lost time, but during a normal April (is there such a thing) 2.5" of snow falls in the Twin Cities, according to the Minnesota DNR.

March precip.

Series of March Near-Misses. The biggest, wettest storms detoured to our south and east for much of March, creating wetter than normal conditions for much of southern and eastern Minnesota, where temperatures were consistently warm enough for mostly-rain. 

Credit: Praedictix.

 

Late springs are trending wetter in recent years, so we could easily lapse into a wetter pattern later in April and May. But the fact that we didn't experience a treadmill of heavy storms in March has been a positive factor in helping to ease the threat of river flooding. 

March Departure

March Precipitation Departure From Normal. Last month was slightly drier than average for roughly the northwestern half of Minnesota, but wetter than normal for southeastern Minnesota and much of Wisconsin - closer to the main superhighway for storms last month. Credit: Praedictix.

 

Temperatures in the Gulf of Mexico are significantly warmer than normal, which often correlates with more severe thunderstorms and tornadoes later in the spring. There's no place for complacency - we've been fairly lucky with the number and intensity of Minnesota tornadoes in recent years. At some point the pendulum swings back in the other direction and we have a busier-than-average tornado season. Don't let your guard down.

CFS1

April Temperature Anomaly Prediction. The latest long-range climate models from NOAA's Climate Forecast System predict a colder than average April for much of the USA, including Minnesota. A correction wouldn't be a surprise, after a meteorological winter that was nearly 3F warmer than average in the Twin Cities. But confidence levels are low that far out. Map credit: NOAA and WeatherBell.

 

In spite of a few more spasms of chilly, Canadian air and even a couple of slushy relapses, spring is coming. 60s return early next week, when a few strong thunderstorms may bubble up - a preview of what's to come.

 

Hang on and enjoy the ride! Because Minnesotans earn their springs.

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