/Issued 3:36 PM CDT, Sunday, April 28, 2019/
Winter Weather Advisory in effect late tonight through late Monday afternoon for the North Shore, Twin Ports and Arrowhead (purple shaded area on map)
…Counties included in the advisory…
Southern St. Louis MN
Here’s my snowfall forecast for Monday.
•Most of the accumulation should occur on grassy surfaces and trees
•Lesser traveled/secondary roads could become snow/slush covered and slippery
•Main roads mostly wet, but there is a chance for them to become snow/slush covered and slippery if the snow falls heavily enough and for a long enough period of time, this possibility is greatest especially north of Duluth
•Reduced visibilities Monday due to falling snow. Potential for some blowing snow especially along the North Shore where east winds could gust to around 30 mph
Should be noted that these late season snow events are very difficult to forecast. If computer models are off by as little as 1-2 degrees in their temperature forecasts, this could lead to more rain than snow (if too cold) or more snow than rain (if too warm) Precipitation rates also play a role, heavier precipitation rates could help cool the atmosphere causing rain to flip over to snow, while lighter precipitation rates could lead to rain being the main precipitation type.
Top 5 snowfall totals for April 29 at Duluth, Minnesota
1: 8.5″ (1989)
2: 3.0″ (1903)
3: 2.0″ (1966)
4: 2.0″ (1909)
5: 1.7″ (1994)
Note: Dating back to 1885, there have only been 6 one-inch or greater snowfall events in Duluth on April 29, most recent was in 1994. 14 measurable snowfall events on record for April 29 (At least 0.1 inch accumulation) Most recent was in 2002.
Low pressure was over the Northern Plains this Sunday afternoon. Winds blow towards the low pressure, seen perfectly on the map below.
Goes-16 water vapor satellite loop from Sunday, April 28, 2019.
System that will affect the Northland Monday is over the Northern Rockies and Northern Plains today. Blizzard warnings and winter storm warnings are in effect in parts of Montana and North Dakota due to this spring storm.
Radar loop ending at 3:45 PM Sunday, April 28, 2019.
18z NAM-WRF model 4-28-19
Radar forecast valid from 7 PM this Sunday evening through late Monday evening.
•Chicago, Illinois picked up 2.5 inches of snow on Saturday, April 27. This was the latest accumulating snow since 1989 (May 6) Source: https://www.weather.gov/lot/
•Rockford, Illinois snowfall total of 3.7 inches on Saturday, April 27. This was the latest 2+” event on record. Previous latest 2+” events were on April 23, 1967; and April 23-24, 1910. Also, this is the latest accumulating snow in Rockford since 1994 (April 30) Source: https://www.weather.gov/lot/
•A record low temperature was set at Madison, Wisconsin for April 28 with a low this Sunday morning of 25 degrees. The previous record low was 27 degrees set in 1988, 1982 and 1966. Source: https://www.weather.gov/mkx/
Anywhere you see green on the map below indicates wet soils as of April 27. This wet pattern is leading to a delay in planting in the Midwest. “The NASS Crop Progress Reports, Missouri has planted 16% of its corn crop, which is only about half the five-year average. Illinois corn was only at 1% planted, compared to its average of 17%”.
Temperature departure map for the week of April 21, 2019. Above normal temperatures last week across the entire Northland.
Precipitation departure map for the week of April 21, 2019. Above normal precipitation totals last week in most of northwest Wisconsin, below normal precip across northern Minnesota.
Temperature and Precipitation report for Duluth, Minnesota
April 21-27, 2019
High Temperatures/Departure from Normal
4/21: 50 F/-2 degrees below normal
4/22: 48 F/-5 degrees below normal
4/23: 59 F/+6 degrees above normal
4/24: 72 F/+18 degrees above normal
4/25: 70 F/+16 degrees above normal
4/26: 54 F/-1 degree below normal
4/27: 55 F/Normal
Low Temperatures/Departure from Normal
4/21: 42 F/+10 degrees above normal
4/22: 32 F/-1 degree below normal
4/23: 29 F/-4 degrees below normal
4/24: 41 F/+7 degrees above normal
4/25: 45 F/+11 degrees above normal
4/26: 37 F/+3 degrees above normal
4/27: 32 F/-3 degrees below normal
Average temperature for the week of April 21: 47.6 degrees (+3.9 degrees above normal) Source: https://www.dnr.state.mn.us
Total precipitation: 0.28 inches
Normal: 0.64 inches
Departure: -0.36 inches below normal
State Average for Minnesota for the week of April 21, 2019
Temperature: 52.1 degrees
Departure: +4.0 degrees above normal
Precipitation: 0.53 inches
Departure: -0.14 inches below normal
Road condition information
Weather Synopsis for Northeast Minnesota and Northwest Wisconsin
Increasing mid and high level cloudiness across the area today with filtered sunshine mixed in. Highs today were near normal to around 5 degrees below normal for April 28 with high temps in the mid 40s to low 50s except for mid 50s along a Siren to Hayward corridor. A rather potent system was over Montana today, and this system will be moving to the E-SE over the next 24 hours and it will bring accumulating snow and a rain-snow mix to the Northland.
Tonight: Low pressure and its inverted trough will head east out of the Northern Plains and into the upper Midwest. Will see precipitation gradually develop over the Northland tonight but it will take some time due to a lot of dry air with Sunday afternoon relative humidity values generally less than 30%, so it will take time for the atmosphere to saturate enough to allow precipitation to reach the surface, this should happen by late tonight/early Monday morning. Also with the amount of dry air over the area, this will help cool the temperatures as the rain falls through this dry air, a process called evaporative cooling. Note: Most of us should see precipitation begin as rain late tonight, but as temps begin to fall, some of us should see a snow-rain mix or even a changeover to all snow take place early Monday morning. Lows tonight will be in the 30s with east winds 5 to 15 mph.
Monday: Not a very nice spring day. A chilly, damp and in some areas a snowy day! A weakening low and trough will move slowly across the upper Midwest Monday, this system will bring rain and snow to the Northland with precipitation lingering into Monday evening in far northeast Minnesota, while elsewhere the precipitation comes to an end during the afternoon. Note: Temperatures aloft are supportive of snow with 850mb temps around -2 to -4C and 925mb temps around -1 to -2C. It will come down to precipitation rates as well as near surface temperature as to what type of precipitation you see on Monday. Most of us should see a period of snow before Noon, then a transition to rain or a rain-snow mix before ending Monday afternoon. The exception to this looks to be in the Arrowhead and higher terrain of the North Shore where enough cold air could remain in place near the surface allowing snow to be the main precipitation type through Monday evening. Highs Monday only in the 30s with lower 40s toward the Brainerd Lakes, normal highs on April 29 are in the mid to upper 50s. Gusty east winds are also expected Monday, strongest along the North Shore (20-30 mph) elsewhere we’re looking at 5 to 15 mph winds.
Cool temperatures should continue midweek, and there is another opportunity for some rain and snow sometime between Tuesday-Thursday, but there is low confidence on the timing and how everything sets-up during the mid week time frame. Stay tuned.
Forecast for Duluth
Event: Winter Weather Advisory
Timing: 10 PM tonight to 7 PM Monday
.Tonight… Mostly cloudy. Rain or a rain/snow mix developing after Midnight. Low 32 to 34. Wind east 10 to 20 mph.
.Monday… Breezy. Snow or a rain/snow mix. Total snowfall accumulations of 1 to 3 inches possible (greatest accumulations on top of the hill, away from Lake Superior) High 34 to 38. Wind east to northeast 15 to 25 mph.
.Tuesday… Mostly cloudy. Light rain or snow possible at times. High 35 to 40. Wind northeast 10 to 20 mph.
Normal temperatures for April 29
April 29 sunrise: 5:57 AM CDT
April 29 sunset: 8:16 PM CDT