/Issued 5:59 PM CDT, Tuesday, May 15, 2018/
Timing could be off a bit from what I have on this map but this is what I have come up with based on model data from this afternoon.
18z NAM-Nest model Simulated Radar Forecast from 1 PM Wednesday to 1 AM Thursday.
Convection Allowing Models (CAMS) are in fairly good agreement for Wednesday afternoon-evening with isolated coverage of showers and thunderstorms in northeast Minnesota and northwest Wisconsin as a cold front moves south through the area along with possible interactions with a southwestward moving lake breeze boundary later in the day.
Lots of sunshine across the Northland today with just a few areas of clouds passing southeast through far northern portions of Minnesota. Highs today were in the low to mid 70s with 40s and 50s near Lake Superior due to a stronger lake breeze today.
A few showers or thunderstorms are possible later tonight into Wednesday morning in far northern Minnesota with a strengthening low level jet/warm air advection pattern developing tonight. Lows tonight ranging from the lower 40s to around 60 degrees, cooler temps near Lake Superior, warmest temps western areas. Highs Wednesday in the 70s and 80s.
Warm air advection will take place tonight with an area of +20 to +24 degree Celsius 925mb temperatures over the Red River Valley shifting E/SE during the night and through Wednesday — This warm air will be found south of a cold front which will be near the Ontario/Minnesota border Wednesday morning, this front will then reach a line from central Minnesota to northern Wisconsin by Wednesday evening.
Although not incredibly moist or unstable south of the cold front Wednesday, there should be enough juice and instability in place to help pop a couple of afternoon/evening showers and thunderstorms in parts of the Northland roughly in the 2 PM to 10 PM time frame with storm movement toward the south and east.
Dew points Wednesday afternoon are expected to be around 50 degrees, maybe into the mid 50s with 850mb dew points around +10C. PWATS climbing to around an inch. CAPE is forecast to remain under 1000 j/kg while mid level lapse rates look on the weaker side, generally around 6.0 c/km. Not much support from the low level jet while mid level winds will be out of the NW at around 30 knots. This basically points to little to no risk for severe weather in our area Wednesday afternoon but remember that lightning is always a hazard from a thunderstorm.
Note: Brief downpours, wind gusts 20-35 mph and occasional lightning are the biggest threats if storms develop Wednesday afternoon.
Record High Temperatures for Wednesday, May 16
International Falls, Minnesota: 87 degrees set on May 16, 1972
Duluth, Minnesota: 84 degrees set on May 16, 1962
Hibbing, Minnesota: 83 degrees set on May 16, 1972
Note: Of those three locations, it looks like Duluth and Hibbing stand the best chance to tie or set a new record high temperature for May 16 (Wednesday)
Will have a wild temperature ride in Duluth on Wednesday with southwest winds most of the day resulting in daytime highs of 80 degrees or a little warmer, then a wind shift to the northeast occurs between 6-8 PM Wednesday with gusts 20-30 mph! Temperatures drop into the 40s Wednesday evening!
Thursday through Saturday will potentially be rainy at times but doesn’t look like continuous rain on those three days. Still some differences on the timing of the rain for later this week with scattered rain showers for Thursday, then Friday could end up mainly dry with rain spreading into the area Friday night, continuing Saturday morning before moving out of our area for Saturday afternoon. Stay tuned as the computer models fine tune the timing of these late week rain chances.
Forecast for Duluth and Superior
.Tonight… Mostly clear. Low 44 to 49. Wind east at 10 to 20 mph becoming southwest after midnight.
.Wednesday… Warmer! Partly to mostly cloudy. Isolated showers and thunderstorms possible between 2 PM-8 PM. Record or near record warmth possible. High 80 to 85. Wind southwest at 10 to 20 mph. Note: Record high for May 16 is 84 degrees set in 1962.
.Thursday… Cooler. Mostly cloudy. A few showers possible. High 50 to 55, 40s near Lake Superior. Wind east at 15 to 25 mph.
Normal temperatures for Wednesday
Sunrise Wednesday: 5:33 AM CDT
Sunset Wednesday: 8:38 PM CDT