/Issued 5:12 PM CST, Thursday, November 30, 2017/
12z GFS model from 11.30.2017
Yes this will be a cold pattern for us once it develops. A ridge over the northeast Pacific/western Canada region with another ridge over Greenland — All of this means that the arctic flood gates will be wide open, and pointed right at the upper Midwest and Great Lakes for early-mid December. Probably a few different shots of cold air with this type of pattern, with each shot being colder than the previous. Will we have lows 20 below, 30 below or colder in the Northland? It’s possible by mid December!
Forecast map valid for Friday evening
18z NAM Nest model simulated radar starting at 11 AM Friday, ending at 2 AM Saturday. Not a lot of precipitation on Friday, but there could be some light rain or wet snow across parts of northern Minnesota during the afternoon-evening hours. Note: Colors on map, green is rain, blue is snow.
Note: Temperature outlook for December looks good to me as we are entering a colder weather pattern which will begin around December 5, once this pattern becomes established it likely won’t change much at least through mid month, so will be dealing with reinforcing shots of very cold temperatures at least through mid December.
Note: With the upper level winds constantly coming out of the north/northwest, I don’t like our odds for getting a significant snowfall in northeast Minnesota or northwest Wisconsin through mid December, but this pattern should be favorable for a few clipper systems that could lay down a few inches of snow if they track through our area and not go too far north or south. I think odds favor near to below average precip/snowfall in most of the Northland for December, but the lake effect snow machine could get going along the South Shore of Lake Superior in northwest Wisconsin so that’ll be something to keep an eye on in coming weeks.
December Climate Normals for Duluth, Minnesota
Temperature: 14.8 degrees
Precipitation: 1.21 inches
Snowfall: 17.7 inches
Normal High on the 1st: 27 degrees; Normal High on the 31st: 19 degrees
Normal Low on the 1st: 14 degrees; Normal Low on the 31st: 3 degrees
Warmest December on record: 38.5 degrees set in 1877
Coldest December on record: 10.2 degrees set in 1983
Wettest December on record: 3.89 inches set in 1879
Driest December on record: 0.07 inches set in 1905
Snowiest December on record: 44.3 inches set in 1950
Least snowy December on record: 0.9 inches set in 1905
Average number of days with snowfall 0.1″ or greater: 13
Average number of days with snowfall 1.0″ or greater: 5
Average number of days with subzero low: 10
Astronomical data for December
Sunrise on the 1st: 7:33 AM CST
Sunrise on the 31st: 7:53 AM CST
Sunset on the 1st: 4:22 PM CST
Sunset on the 31st: 4:30 PM CST
Note: Today marks the final day of Meteorological fall 2017, the period from September 1 through November 30. Preliminary stats for Duluth, Minnesota – Final numbers released on Friday.
~6 degrees colder vs. last fall
~0.60 inches wetter vs. last fall
~13 inches more snow vs. last fall
Above normal temperatures to continue through the weekend. Generally speaking will maintain a zonal west-east flow through Saturday before a trough moves into the Rockies which will help shift the flow to the southwest, once this trough moves away, that will signal the start of the shift in the upper level wind pattern from west-east to more north-south or northwest-southeast — Net result from all this is for more continued mild temperatures through Monday before we see colder temperatures move in by the middle of next week.
Another fast moving but weak low pressure system will skirt along the U.S./Canadian border on Friday, this system might wring out a little bit of rain or wet snow in northern Minnesota, mostly north of Duluth. Otherwise we’re looking at mainly dry weather through Sunday morning.
Chances for rain are forecast to increase across the Northland for Sunday and Sunday night with lingering rain possible on Monday. This precipitation will occur as low pressure tracks E/NE out of the Rockies while an upper level trough passes through the upper Midwest. Note: Cold air will be lacking with this system, so most of the precipitation should be in the form of rain with the exception possibly in far northern Minnesota where some snow is possible Sunday night or Monday.
As colder air pours into the Northland Monday night or Tuesday will probably see some snow showers develop with a dusting of accumulation possible.
Highs for Friday, Saturday and Sunday should range from the mid 30s to mid 40s, keep in mind that normal highs for the first few days of December are in the mid 20s.
Forecast for Duluth and Superior
.Tonight… Partly to mostly cloudy. Low 27 to 32. Wind west at 10 to 20 mph becoming southwest.
.Friday… Partly to mostly cloudy. High 38 to 43. Wind southwest at 10 to 15 mph becoming east.
.Saturday… Partly to mostly cloudy. High 37 to 42. Wind southwest at 10 to 15 mph.
Normal temperatures for Friday
Sunrise Friday: 7:33 AM CST
Sunset Friday: 4:22 PM CST