The final week of meteorological summer 2019 will be rainy at times, especially the period from Monday through Wednesday. Note: Going into today (August 25) Duluth is around -1.40″ below normal in rainfall for the month, and since June 1 we’re around -2.75″ below normal.
The first of what should be a few rounds of rain to affect the Northland in the coming days is moving northeast out of central Minnesota late this Sunday afternoon. Note: Reminder that Duluth’s radar (KDLH) is out of service until later this week as a major system upgrade continues. Alternate radar sites are Grand Forks (KMVX) or Minneapolis (KMPX)
Much of the Northland could get 1 to 2 inches of rain by Wednesday morning with isolated totals of more than 3 inches possible.
Source: 18z NAM model; https://www.tropicaltidbits.com
Radar forecast valid from 7 PM Sunday to 7 AM Tuesday. Source: 18z NAM-WRF model; https://weathermodels.com
Source: 12z NAM model; https://weather.cod.edu
An impressive shot of cold air advection is possible late Tuesday into Wednesday. I believe this is the first time since last spring where we have blue colors showing up on the 850mb temperature map, another sign that fall is approaching. Note: You start thinking about snow when the 850mb temp falls to 0C, but we won’t be seeing any snow this week as the surface temps are just too warm to produce anything other than rain.
Wednesday looks like the chilliest day of the week with potential for daytime highs struggling to hit 50 degrees in the Arrowhead and Borderland areas. Might struggle to hit 60 degrees in Duluth. Note: Normal highs in late August are still in the lower 70s.
Note: The average temperature last week at Duluth, Minnesota was below normal for the first time in 8 weeks! You have to go back to the week of June 16 to find the last time where Duluth’s average temperature for a 7-day period was below normal.
The list below shows the average temp and departure from normal for the weeks from June 16 through August 18.
- June 16: 60.1 degrees (-1.0 degree below normal)
- June 23: 67.1 degrees (+4.1 degrees above normal
- June 30: 71.8 degrees (+7.2 degrees above normal)
- July 7: 70.4 degrees (+4.7 degrees above normal)
- July 14: 73.5 degrees (+7.2 degrees above normal)
- July 21: 71.6 degrees (+5.3 degrees above normal)
- July 28: 68.5 degrees (+2.5 degrees above normal)
- Aug. 4: 69.1 degrees (+3.5 degrees above normal)
- Aug. 11: 67.4 degrees (+2.5 degrees above normal)
- Aug. 18: 63.7 degrees (-0.1 degrees below normal)
Temperature and Precipitation report for Duluth, Minnesota
August 18-24, 2019
High Temperatures/Departure from Normal
- 8/18: 74F/Normal
- 8/19: 80F/+6 degrees above normal
- 8/20: 82F/+8 degrees above normal
- 8/21: 74F/Normal
- 8/22: 68F/-5 degrees below normal
- 8/23: 71F/-2 degrees below normal
- 8/24: 74F/+1 degree above normal
Low Temperatures/Departure from Normal
- 8/18: 54F/-1 degree below normal
- 8/19: 52F/-2 degrees below normal
- 8/20: 57F/+3 degrees above normal
- 8/21: 51F/-3 degrees below normal
- 8/22: 52F/-2 degrees below normal
- 8/23: 47F/-7 degrees below normal
- 8/24: 56F/+3 degrees above normal
Average temperature for the week of August 18: 63.7 degrees (-0.1 degrees below normal) Source: https://www.dnr.state.mn.us
- Total Precipitation: 0.25″
- Normal: 0.85″
- Departure: -0.60″ below normal
State Average for Minnesota for the week of Aug. 18, 2019
- Temperature: 65.1 degrees
- Departure: -2.5 degrees below normal
- Precipitation: 0.86″
- Departure: +0.07″ above normal
Temperature departure map for the week of August 18, 2019. Source: https://hprcc.unl.edu
Almost the entire Northland had below average temperatures last week, although there was one small area with near normal temps (yellow area on map)
Precipitation departure map for the week of August 18, 2019.
A few pockets with above normal precipitation in the Northland last week (green and blue colors on map) but most of the area had below normal precipitation last week.
An upper level low and upper trough will deepen early this week as it moves across central Canada, upper Midwest and Great Lakes. Much cooler temperatures will be found on the backside of this system with the coolest temps forecast to occur Tuesday and Wednesday.
Source: 12z European Ensemble model; https://weathermodels.com
Low temperature forecast for Monday morning, August 26. Source: https://graphical.weather.gov
High temperature forecast for Monday, August 26
A strong storm system (autumn like) will be impacting the Northland through midweek.
Energy to our northwest and southwest this afternoon will attempt to phase a bit during the next 24-36 hours, how much phasing occurs is still a bit uncertain, but there is potential for a deep surface low to develop by Tuesday with a central pressure down to around 985mb just northwest of Lake Superior. Note: Gale force wind gusts out of the west/northwest are possible over western Lake Superior from Tuesday into Wednesday if this system deepens enough.
As this system intensifies winds will increase out of the west by late Monday night or Tuesday with wind gusts of 20 to around 35 mph possible across much of the Northland on Tuesday, which could linger into Wednesday.
Cold air advection will also occur on the backside of this system with 850mb temperatures of +1 to +5C spilling into the Northland for Tuesday and Wednesday.
Low level moisture will continue to increase ahead of this system tonight thanks to a southerly flow with precipitable water of around 1.30 to 1.60 inches building into the Northland — Better forcing with the approach of a cold front will cause rain to become more widespread in our area tonight into Monday night with some breaks likely to occur in between the waves of precipitation. We could also see a few thunderstorms develop in the Northland along a cold front Monday afternoon-evening, but instability looks fairly limited due to the expected cloud cover and precipitation.
Lows tonight will be on the mild side because of the clouds, lows will be in the mid 50s to low 60s. Highs Monday in the 60s in northern Minnesota with low to mid 70s in northwest Wisconsin and far eastern Minnesota.
Occasional showers will continue Tuesday and Wednesday as moisture wraps around a low pressure system which will be off to our north.
Will dry out late this week, although there will be another cold front moving through the area Thursday, but right now this front looks to come through on the dry side.
Forecast for Duluth and Superior
.Tonight… Occasional showers developing. Mostly cloudy. Low 57 to 62. Wind south to southeast 10 to 20 mph.
.Monday… Occasional rain (dry hours mixed in) Mostly cloudy. High 66 to 71. Wind east to southeast 10 to 20 mph.
.Tuesday… Breezy. Mostly cloudy. Occasional showers. A thunderstorm also possible. High 60 to 65. Wind west 15 to 25 mph.
Normal temperatures for August 26
- High 73
- Low 53
- Sunrise Monday 6:20 AM CDT
- Sunset Monday 8:00 PM CDT
Thanks for reading!