Isolated to scattered strong to severe thunderstorms possible in parts of the Northland Monday

There is another chance for some strong to severe thunderstorms over parts of northeast Minnesota and all of northwest Wisconsin on Monday. The risk for severe weather is greatest (slight risk) across southern portions of the area, from Squaw Lake and Hibbing, east toward Silver Bay, including all of east-central Minnesota, Twin Ports, Brainerd Lakes and all of northwest Wisconsin.

Primary severe weather threats on Monday include

Damaging wind gusts of 60 to 70 mph

Large hail of 1″ to 1.50″ in diameter (quarter to ping pong ball size)

Note: All storms will produce torrential rainfall and frequent lightning.

Stay Weather Aware on Monday!

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Monday’s setup includes a cold front (blue line on map) dropping south out of northern Minnesota while a warm front (red line on map) moves east out of western/southwestern Minnesota.

Southerly low level winds will transport a more humid air mass northward into the area on Monday with dew points climbing into the upper 50s to middle 60s. The atmosphere is also forecast to become more unstable especially over southern portions of the Northland where CAPE could build to ~1500-2500 J/kg by Monday afternoon-early evening. Mid level lapse rates look more impressive with Monday’s setup compared to past setups we’ve had this summer, with values of 7.0-8.0 C/km possible over much of the Northland on Monday, this could increase the risk for large hail to accompany a few of the storms on Monday.

Winds aloft also look fairly strong on Monday, from the upper levels to the lower levels of the atmosphere, and will also have a decent amount of wind shear over the area, and a change of wind direction with height, with southerly surface winds veering southwest at 850mb, and northwest at 500mb — This could lead to a few supercell or rotating thunderstorms later Monday afternoon into Monday evening with an increased risk for damaging winds and or large hail, again especially over southern portions of the Northland.

As for timing of Monday’s storms, looks like the afternoon and evening holds the greatest chance for possible strong to severe thunderstorms in parts of the Northland, but a few showers or thunderstorms are even possible Monday morning, but these shouldn’t be severe if storms occur during that time.

12z model run simulated radar forecast valid from 7 AM Monday to Midnight.

NAM 3km model

HRRR model

Tim

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