/Issued 5:43 PM CDT, Wednesday, September 19, 2018/
Source: https://www.spc.noaa.gov
Source: https://weathermodels.com
12z European computer model (ECMWF) 9-19-2018
Source: https://www.wpc.ncep.noaa.gov
Source: https://weather.cod.edu
Ingredients are already in place for Thursday’s storm including a plume of deep moisture stretching from Mexico to the upper Midwest, strengthening jet stream winds to our north and also off to our west while energy approaches from the Pacific northwest while low pressure heads NE out of Colorado.
Source: https://weathermodels.com
12z European computer model (ECMWF) 9-19-2018
Scattered strong to severe thunderstorms are expected Thursday across much of southern/eastern Minnesota into central/northern Wisconsin. Large hail and damaging winds will be the main severe weather threats, but a few tornadoes are also possible especially in the Enhanced Risk area Thursday afternoon-evening. Stay Weather Aware!
Source: https://weather.cod.edu
18z NAM-Nest model
Updraft Helicity Forecast valid from 7 AM Thursday to 10 PM Thursday — This shows where there is potential for rotating thunderstorms (Supercell development) for Thursday shown by the green, yellow, orange and red colors on the map.
A few towns in far northern Minnesota could see their first snow flurries of the season Friday morning!
Source: https://weather.cod.edu
18z NAM-Nest model 9-19-2018
Simulated Radar Forecast valid from 5 AM Friday to 2 PM Friday.
Not a certainty just yet, but its possible if the cold air comes in quick enough that will see the rain mix with some snow Friday morning in a few spots across far northern Minnesota, the NAM model shown below shows this possibility (Blue colors=Snow)
Source: https://www.tropicaltidbits.com/
12z European Ensemble model (EPS) 9-19-2018
Weather Synopsis
Skies were mostly cloudy today over most of the Northland except in far northern Minnesota where skies were sunny at times. Highs ranged from the lower 60s from Bigfork, Orr, Cook, Crane Lake to International Falls with 50s elsewhere.
Surface map at 5 PM had an area of low pressure ~1002mb over eastern Colorado with a warm front from central Nebraska to central Iowa. An upper level trough covered the Pacific northwest while winds aloft turn SW ahead of this trough.
[Tonight]
A few showers are possible tonight in eastern Minnesota and northwest Wisconsin. Partly to mostly cloudy with lows ranging from the lower 40s in far northern Minnesota to the 50s in eastern Minnesota and northwest Wisconsin. East winds near Lake Superior gusting to around 20 mph.
[Thursday]
Forcing will increase Thursday as low pressure approaches from the SW while an upper trough swings in from the W, in addition to this will be stronger winds aloft which will setup to our N-NE and to our W — All of this points to what should be a tremendous amount of lift in the atmosphere which will lead to widespread rainfall in northeast Minnesota and northwest Wisconsin.
As the low and warm front approach from the southwest in the afternoon/evening, heavier rain and embedded thunderstorms will be possible as warm air advection and moisture advection is maximized especially from east-central Minnesota into northwest Wisconsin — A few of the storms could become strong to severe Thursday afternoon/evening with large hail and damaging wind gusts being the primary hazards in eastern Minnesota and northwest Wisconsin, but an isolated risk for tornadoes could also develop early Thursday evening (~5 PM to 9 PM) from Hinckley and Pine City toward the Hayward lakes.
Note: Strong northeasterly winds will also occur especially near Lake Superior Thursday and Thursday evening with wind gusts from 30 to around 50 mph.
[Looking Ahead]
Low pressure will continue to impact the Northland Friday as it lifts NE out of east-central Lake Superior. Gusty NW winds and cold air advection will be occurring on the backside of this low with lingering rain showers which will come to an end from W-E by Friday afternoon.
Our next shot for precipitation occurs later in the weekend as low pressure heads NE out of the northern Plains — This system should bring another round of rain and possibly a few thunderstorms to the Northland Sunday into Monday. There is also a chance for a rain/snow mix in extreme northern Minnesota Saturday night and Sunday.
Duluth, Minnesota Climate Normals for September 20
High: 63
Low: 44
Sunrise Thursday: 6:53 PM CDT
Sunset Thursday: 7:10 PM CDT
Tim