Risk for strong to severe t-storms Friday in eastern MN and northern WI

Northland Storm Reports for July 17-18, 2019

2:33 PM (7/18) TORNADO — 11 miles ENE Gordon, WI (Douglas County)

12:00 PM (7/18) HAIL — 1.25 inch. Foxboro, WI (Douglas County) Half dollar size hail.

9:48 PM (7/17) HAIL — 0.25 inch. 7 WSW Hovland, MN (Cook County)

8:30 PM (7/17) FLOOD — 1 N International Falls, MN (Koochiching County) Floodwater covering US Highway 53 in International Falls.

8:12 PM (7/17) WATERSPOUT — 2 SW Cusson, MN (St. Louis County) Waterspout video from Pelican Lake Resort.

8:06 PM (7/17) TORNADO — 10 NNE Kabetogama, MN (St. Louis County) Tornado reported with trees down near houseboats on Saginaw Bay and Marion Bay.

8:05 PM (7/17) THUNDERSTORM WIND DAMAGE — 10 NNE Kabetogama, MN (St. Louis County) Voyageurs NP reports many trees down at houseboat site on Duckfoot Island.

8:03 PM (7/17) HAIL — 0.25 inch. Island View, MN (Koochiching County)

Note: Record rainfall at International Falls, Minnesota on Wednesday, July 17, 2019. New record 2.21 inches. Previous record 1.78 inches set on July 17, 1978.

Rainfall Reports for July 17-18, 2019

Source: https://www.weather.gov/dlh/

  • International Falls, MN: 2.21 inch
  • Grand Portage, MN: 1.82 inch
  • 3 E Orr, MN: 1.44 inch
  • Grand Marais, MN: 1.30 inch
  • Barnes, WI: 1.29 inch
  • Kabetogama, MN: 1.10 inch
  • Solon Springs, WI: 1.10 inch
  • Littlefork, MN: 1.07 inch
  • 12 N Grand Rapids, MN: 0.85 inch
  • Clam Lake, WI: 0.66 inch
  • 2 E Celina, MN: 0.51 inch
  • Ashland, WI: 0.51 inch
  • Cook, MN: 0.47 inch
  • Ely, MN: 0.44 inch
  • 10 W Gunflint Lake, MN: 0.37 inch
  • 4 S Bruno, MN: 0.35 inch
  • Hayward, WI: 0.27 inch
  • Minong, WI: 0.23 inch
  • Hibbing, MN: 0.16 inch
  • Siren, WI: 0.16 inch
  • 4 E Island Lake, MN: 0.14 inch
  • Duluth Airport: 0.13 inch

Portions of the Northland are in a slight risk for severe thunderstorms on Friday, this risk area includes portions of far eastern Minnesota and northwest Wisconsin, roughly along and south/east of a line from about Hinckley to Gordon, Grand View to Upson.

There is a lesser risk (marginal) for severe weather on Friday farther north in the blue shaded area on the map.

Note: Main threats from severe storms on Friday are from damaging winds and large hail with an isolated tornado also possible, again the risk area is highest from far eastern Minnesota into parts of northwest Wisconsin, south of Duluth and Superior.

Forecast models are showing an incredible amount of potential energy (CAPE) on Friday with values of 4000-8000 J/kg over the southern half of Minnesota, often times will see severe weather develop on the northern edge of the most extreme instability which I highlighted in black.

Source: https://weathermodels.com

One big issue with Friday’s severe setup are the very warm temperatures aloft. Forecast models are showing H7 temperatures of +14 to +16C across the southern half of Minnesota with the +12C contour poking north into central Minnesota and north-central Wisconsin. Thunderstorms should first develop closer to where the +12C 700mb temperature line will be, then we could see these storms drop farther to the south/east Friday evening or during the overnight.

Source: https://weather.cod.edu

Here’s the 18z HRRR model run from Thursday.

Radar forecast from 7 PM Thursday to 1 AM Saturday.

Source: https://weathermodels.com

Will see some changes in the upper level pattern by late this weekend. Right now were in a fast generally zonal (west to east flow) but by late this weekend winds aloft shift out of the northwest thanks to a developing upper level ridge across the western U.S. and a trough which pushes east out of western Canada. Relief from the heat and humidity will occur this weekend, but there are signs showing up in model data that the warm pattern could possibly return by mid to late next week.

This is about as textbook of a supercell, hook echo radar representation as you will see around here — This radar image was from earlier this Thursday afternoon when a tornado was reported about 11 miles east-northeast of Gordon, Wisconsin. Rain and possible hail to the east with a wall cloud (lowering/rotation, and possible tornado) on the southwest side of the supercell.

Weather Synopsis for Northeast Minnesota and Northwest Wisconsin

*Today (July 18) Another very warm day across the Northland with highs topping out in the 80s. Also was quite muggy with dew points ranging from the lower 60s to lower 70s. Scattered strong to severe thunderstorms occurred at times especially late this morning into the midday hours in parts of northwest Wisconsin with other showers and thunderstorms impacting the Arrowhead of Minnesota.

*Tonight: The atmosphere has become a little more stable late this afternoon compared to earlier in the afternoon, and this trend should continue tonight, with that said there is still plenty of wind shear over the area, and if a thunderstorm develops it could become severe, the chances for a few spotty thunderstorms appear greatest up near the Ontario border tonight. Mild temps under partly to mostly cloudy skies, patchy fog possible along the North Shore. Lows tonight ranging from the upper 50s to around 70 degrees.

*Friday (July 19) One more warm and humid day on the way with highs in the 80s, a few locations in eastern Minnesota and northwest Wisconsin could be up around 90 degrees. Muggiest conditions will be across southern portions of the area on Friday with dew points in the mid 60s to mid 70s. Not nearly as humid along and north of HIghway 2 in northeast Minnesota with dew points in the 50s to lower 60s. A cold front will be moving south/east through the area on Friday, this front will be a source of lift as it scoops up the warm/humid air. We should see scattered showers and thunderstorms Friday into Friday night across the area with the greatest threat for severe thunderstorms and heavy rainfall extending from far eastern Minnesota into southern portions of northwest Wisconsin.

It’s an impressive setup for severe weather on Friday with strong winds aloft over the upper Midwest. 50-70 knot winds at 500mb. Upper level winds of 100-145 knots off to our north. There should be plenty of wind shear in place on Friday, hence the risk for severe weather in eastern Minnesota and north-central Wisconsin.

…Looking Ahead…

A much less humid weekend is on the way along with cooler temperatures. Highs Saturday and Sunday should mainly be in the 70s, although some locations might not get out of the 60s on Saturday. Dew points falling into the 50s/lower 60s this weekend. There is a chance for some rain and isolated thunderstorms Saturday from Brainerd and Walker, east to Duluth, including all of northwest Wisconsin, this rain would end from west to east Saturday afternoon/evening. Sunday looks mostly dry at the moment.

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