Saturday, June 18, 2016

June 18, 2016: Very warm, muggy and breezy on Sunday (SW wind) A chance of strong to severe thunderstorms through Sunday evening

/Issued 4:01 PM CDT, Saturday, June 18, 2016/

The Storm Prediction Center has increased the threat of severe thunderstorms to an enhanced risk for Sunday afternoon and evening in central Minnesota into parts of eastern and southern Minnesota

Potential for a few significant severe weather events within the white outlined area on the map.

Area most at risk from thunderstorms for tonight

Sunday morning

Late Sunday afternoon/evening -- Note:  Storms will eventually move into portions of northwest Wisconsin Sunday evening.

Low temperature forecast for tonight.  Source, National Weather Service Duluth, Minnesota.

High temperature forecast for Sunday.  Source, National Weather Service Duluth, Minnesota.

Weather Summary for NE Minnesota and NW Wisconsin
Date:  June 18, 2016

A nice, warm and somewhat muggy day across the Northland under partly to mostly cloudy skies. highs were in the mid 70s to low to mid 80s with dew points generally in the mid 50s to mid 60s.  So far so good in terms of the lack of convection today.  Moisture and instability is there for storms and there's also a trigger in the form of a surface boundary which extends from west central through northeast Minnesota but other than a spotty shower or two it's been a dry day in the Northland.

Forecast Discussion for NE Minnesota and NW Wisconsin

Confidence:  Medium.

Tonight:  Mild and humid conditions under partly to mostly cloudy skies.  Still could see a few showers and thunderstorms develop at times most likely across northern Minnesota.  Lows will be in the 60s to around 70 degrees with south or southeast winds at 5 to 15 mph.  A warm front will be lifting north through the Northland tonight and its this boundary that when combined with the humidity and instability in place could help spark a few storms through the night.

Sunday:  Very warm, breezy and muggy.  Highs are expected to be in the 80s to lower 90s with south/southwest winds at 15 to 25 mph.  Dew points will be in the 65 to 75 degree range with afternoon heat indices peaking in the upper 80s to middle 90s in parts of the Northland.

A morning round of showers and thunderstorms could affect northern Minnesota, most likely from the Iron Range on north.

A cold front will move into the area from the west late Sunday afternoon -- The atmosphere should be quite unstable as this boundary approaches.

CAPE of 2000-4000 j/kg; Lifted Indices of -4 to -9C; Mid level lapse rates averaging 7.0-7.5 c/km; Strong winds aloft including 50-70 knot mid level winds and over 100 knot upper level winds over northwestern Minnesota.  Shear looks impressive with 40-60 knots of 0-6 KM Bulk Shear and Effective Bulk Shear per SREF model.

Scattered severe thunderstorms including the potential for supercells increases after 4 or 5 PM on Sunday the way it looks now.