Thundery awakening; Instant summer Tuesday…First 80s?

Nature’s alarm clock rang early and often today as thunder rolled through Minnesota.

A cluster of thunderstorms developed in South Dakota last night and pushed steadily east through Minnesota overnight. The result was heavy rain, hail, gusty winds and a lot of lighting.

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Arc of storms rolls through this morning. Note the (non-severe) “bow echo” on the front of the line. Black dots indicate numerous lightning strikes.

There were no reports of actual severe weather early this morning, but numerous reports of hail. (Remember “severe hail” = 1″ diameter.)

MPX: Eden Prairie [Hennepin Co, MN] trained spotter reports HAIL of marble size (M0.50 INCH) at 06:05 AM CDT –

MPX: Shakopee [Scott Co, MN] trained spotter reports HAIL of nickel size (M0.88 INCH) at 05:59 AM CDT –

MPX: Osceola [Polk Co, WI] trained spotter reports HAIL of nickel size (M0.88 INCH) at 06:53 AM CDT –

MPX: Shakopee [Scott Co, MN] trained spotter reports HAIL of penny size (M0.75 INCH) at 05:53 AM CDT –

MPX: Dayton [Hennepin Co, MN] trained spotter reports HAIL of penny size (M0.75 INCH) at 05:48 AM CDT –

MPX: 1 E Shakopee [Scott Co, MN] trained spotter reports HAIL of penny size (M0.75 INCH) at 05:55 AM CDT –

MPX: 2 W Prior Lake [Scott Co, MN] trained spotter reports HAIL of marble size (M0.50 INCH) at 05:48 AM CDT —

The storms dupmed some significant rainfall this morning.

.63″ Huttner Weather Lab in Deephaven

.42″ MSP Airport

.44″ Eden Prairie

.96″ Lakeville

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NEXRAD storm total rainfall shows widespread .30″ to .60″ rainfall with isolated 1″ to 2″ pockets overnight between Willmar & Glenwood.

Anatomy of an MCS:

The cluster of storms that rolled through this morning was what we call and MCS, or “mesoscale convective system.” These storm super clusters operate on a much bigger scale than “regular” individual T-Storms, travel hundreds of miles, and can persist for several hours or even days in some cases.

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1km visible satellite image of morning storm cluster over Minnesota. Note the bumpy clouds (tall thunderheads) on the system’s leading edge.

Though this system was largely “non-severe” in Minnesota, MCS are often responsible for widespread severe weather. Many big Minnesota “blowdown type” storms are the result of MCS.

Shelf clouds visible?

It’s sometimes tough to pinpoint cloud types from photos, but check out this great shot by Griff Wigley from Northfiled as the storms rolled in this morning.

It is probably a shelf cloud…a common feature at the front end of MCS.

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Griff Wigley captures a likely “shelf cloud” with some illumination rolling thorugh Northfiled this morning.

Free Fertillzer!

If you notice your grass greening up it may be because this mornings storms provded some free fertilizer. The intense energy released by lightning causes “nitrogen fixation” and oxygen to fuse and produce nitrates, which falls as fertilizer.

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Lightning also produces atmospheric ozone.

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Quieter day ahead:

The atmosphere should stabilize the rest of Monday as warm air pushes north. We may see the sun peek out this afternoon from west to east.

Instant Summer Tuesday?

The storms you heard this morning are the sound of summer surging north.

A warm front will sail through Tuesday. As it does, and if we get enough sun temperatures should push into the 80s Tuesday afternoon.

One technique for estimating high temperatures is to use forecast temperatures about a mile up. This so called “850mb” temp technique suggest we could be as warm as upper 80s to near 90 degrees late Tuesday if everything went just perfectly. More likely we will top out somewhere in the low to mid 80s in much of southern Minnesota.

Warmest in 7 months?

The last time we were this warm was early October of last year. We hit 87 degrees on October 10th. It’s been a long time!

Humid too!

The warmth and some humidity will make it feel like instant July. Dew points could soar into the upper 60s to near Tuesday!

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Slight severe risk?

With summer-like heat and humidity levels we could trigger a few storms late Tuesday. SPC has a slight risk out for parts on Minnesota.

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Get ready for instant summer!

PH

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