Normals and records for September at Duluth, MN; Past snowfall totals for September; Outlook for September 2022

5:56 PM Wednesday, August 31, 2022

Meteorological fall 2022 (the period from September 1st to November 30th) begins on Thursday.

Days continue to get shorter during the month of September with a sunset time occurring before 7 PM in Duluth starting on the 25th.

It can snow in Duluth in September, although it doesn’t happen very often. The last time we saw snow in Duluth in September was in 2012, and before that September 1995.

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Here’s a look at the normals and records for Duluth, Minnesota for the month of September using the 1991-2020 climate period.

Normal high on the 1st: 73
Normal high on the 30th: 61

Normal low on the 1st: 52
Normal low on the 30th: 42

Average monthly temperature for September 57.3 F

Warmest: 62.6 F set in September 1897
Coldest: 47.8 F set in September 1974

Normal precipitation 3.48″

Wettest: 11.52″ set in September 1881
Driest: 0.19″ set in September 1952

Normal snowfall: 0.1″

Snowiest: 2.4″ set in September 1991

Average number of 80-degree days in September: 2

Average number of days with a low of 32 or colder: 1

Average date for first 32 degree or colder minimum temperature is September 30. Last year’s 1st 32 or colder minimum temperature didn’t occur until October 21.

Astronomical Data for September at Duluth

Sunrise on the 1st: 6:28 AM CDT
Sunrise on the 30th: 7:05 AM CDT

Sunset on the 1st: 7:48 PM CDT
Sunset on the 30th: 6:49 PM CDT

The autumnal equinox or the official start to fall 2022 begins at 8:03 PM Thursday, September 22, 2022.

Note: Only 9 Septembers dating back to 1872 have had at least 0.1″ of snow, with the most recent occurring in September 2012. Here are the years that saw at least 0.1″ of snow in September (1908, 1912, 1927, 1928, 1974,1985, 1991, 1995 and 2012)

Note: Only 11 Septembers dating back to 1872 have had at least one day with a high of 90 or warmer in Duluth, with the most recent occurring in September 1984. Here are the years that saw at least one day with a high of 90 or warmer in September at Duluth (1874, 1891, 1894, 1929, 1931,1947, 1961, 1976, 1978, 1983 and 1984.
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Long range forecast for September 2022

Temperature

Above normal temperatures are forecast in northeast Minnesota and northwest Wisconsin for September 2022, but that doesn’t mean we won’t get some shots of cooler temperatures mixed in, in fact much of the Northland typically gets a first frost in September.

Temperature trend for September 2022 per last 10 CFS model runs.

Above normal temps in orange and red
Below normal temps in blue

Precipitation

Below normal precipitation is forecast across northern Minnesota for September 2022, while near normal precipitation is forecast for the North Shore and northwest Wisconsin.

Precipitation trend for September 2022 per last 10 CFS model runs.

Below normal precip in yellow
Above normal precip in green

Here’s what the 500mb pattern is forecast to look like for September 2022 per CFS model.

Thanks for reading!

Tim

More nice weather on the way; Warm temperatures Thursday and Friday followed by a cooling trend this weekend, but warmer temperatures are possible again next week; Isolated showers/t-storms possible Friday PM in parts of northwest WI

4:57 PM Wednesday, August 31, 2022

A prolonged period of dry or mostly dry weather is expected in northeast Minnesota and northwest Wisconsin over the next 7+ days.

Our current warm spell will continue Thursday with highs mainly in the middle 80s across the Northland, but a few locations may see temperatures climb into the upper 80s, that’s pretty warm for the 1st of September, but still shy of the record highs on September 1st, although Hibbing’s record high of 87 on September 1st may be in jeopardy of being tied on Thursday.

Warm temperatures continue in eastern Minnesota and northwest Wisconsin Friday with highs in the 80s, but a cooling trend begins across northern Minnesota with highs Friday in the 70s.

A more pronounced cooling trend occurs on Saturday with highs in the mid 60s to around 70, but after that it looks like will be turning warmer again for next week.

Note: Duluth recorded another 80-degree day today, Wednesday, August 31. This brings our monthly total to 5 days with a high of at least 80 (normal in August is 8 days). Will finish the summer of 2022 with 23 days with a high of 80 or warmer at Duluth (normal in a summer is 25 days) And this summer saw far fewer 80-degree days compared to last summer which had 46 days at or above 80 in Duluth.

The only chance for a few isolated showers or thunderstorms through late next week occurs on Friday (September 2), and that chance is mainly for northwest Wisconsin.

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We may see a line or a broken line of showers and thunderstorms fire up late Friday afternoon-early Friday evening from southern Minnesota into west-central and northeast Wisconsin into western upper Michigan as a cold front moves SE across the region.

There looks to be ample instability for convection ahead of this front on Friday with computer models showing CAPE >2000 J/kg along with steep mid-level lapse rates, but capping may be an issue with 700mb temperatures around +10C, but this cap may weaken enough to allow the development of some storms late Friday mainly in the area outlined in red.

Note: These rain chances on Friday will remain south/east of Duluth.

Here’s the NAM 3km model radar forecast valid at 7 PM Friday.

A brief bout of mugginess is expected on Friday from northeast and eastern Minnesota into northwest Wisconsin with dew points in the 60s, but this won’t last long as a much drier air mass pushes south out of northern Minnesota this weekend.

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Precipitation anomaly through next Friday morning, September 9, 2022.

A near zonal or west to east flow is expected in the Northland for next week with a trough to the south-southeast, and a ridge to the southwest.

Temperatures are forecast to be above normal next week in northeast Minnesota and northwest Wisconsin with a chance for at least another 80-degree day, and possibly multiple 80-degree days for the middle to end of next week.

Thanks for reading!

Tim

A stretch of nice weather as we head toward the end of meteorological summer 2022; Local Storm and Rainfall Reports from Sunday night

4:55 PM Monday, August 29, 2022

Today (Monday) was likely our coolest day of the week as highs today were generally in the mid 60s to low-mid 70s across the Northland.

A warming trend begins Tuesday with highs in the 70s, with even warmer temperatures expected Wednesday, Thursday and Friday with highs getting into the 80s in parts of the Northland, and those that fail to climb into the 80s will still be in the mid to upper 70s, not bad at all as we head toward the end of meteorological summer (August 31) and head toward the start of meteorological fall (September 1).

About the only real weather issue the next few days will be continued breezy northwesterly winds with gusts to 25 mph expected again Tuesday and Wednesday.

Little if any rain chances ahead in the Northland at least through early next week, but a cold front will be moving across the Northland on Friday but at the moment it doesn’t look like will get any precipitation with that frontal passage.

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Local Storm Reports from Sunday night-early Monday morning, August 28-29, 2022.

Source: NWS Duluth, MN

1:35 AM 8/29: Marine Thunderstorm Wind 40 mph. 13 NE Sand Bay, WI at Devils Island Lighthouse.

12:35 AM 8/29: Thunderstorm Wind Damage. 5 NW Hayward, WI (Washburn County) Law enforcement from Washburn and Sawyer Counties reported that there were several locations within each county with smaller trees and branches down due to strong winds.

12:08 AM 8/29: Thunderstorm Wind Damage. 1 W Solon Springs, WI (Douglas County) A sign was blown over near mile marker 202 along Highway 53 near Solon Springs.

10:00 PM 8/28: Hail 0.25 inch. 4 SE Coleraine, MN (Itasca County)

9:49 PM 8/28: Hail 0.75 inch. 2 NE La Prairie, MN (Itasca County)

9:47 PM 8/28: Hail 0.50 inch. 4 W Blackberry, MN (Itasca County)

9:46 PM 8/28: Hail 0.50 inch. 1 N Grand Rapids, MN (Itasca County)

9:45 PM 8/28: Hail 0.75 inch. 5 S La Prairie, MN (Itasca County)

9:44 PM 8/28: Hail 0.50 inch. 1 W Grand Rapids, MN (Itasca County)

8:50 PM 8/28: Hail 1.50 inch (ping pong ball size hail) Boy River, MN (Cass County)

8:47 PM 8/28: Hail 0.25 inch. Boy River, MN (Cass County)

8:40 PM 8/28: Hail 1.75 inch (golf ball size hail) Brevik, MN (Cass County)

8:15 PM 8/28: Hail 0.70 inch. 1 NNE Walker, MN (Cass County)

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Here’s a look at radar estimated rainfall totals from Sunday night through early Monday morning.

Note that dry pocket outlined in white stretching from far northern Pine County through parts of Carlton and Douglas County while heavier rain fell north and south of that area.

Rainfall Reports from Sunday evening-early Monday morning, August 28-29, 2022.

Source: NWS Duluth, MN

2.8 NE Oliver, WI: 2.85″
5 NNW Knife River, MN: 2.53″
4 NE Rice Lake, MN: 2.50″
2.4 S Meadowlands, MN: 2.14″
11.8 NNE Duluth, MN: 2.11″
0.5 E Floodwood, MN: 1.82″
1 WSW Two Harbors, MN: 1.78″
7 N McGregor, MN: 1.64″
Cotton, MN: 1.62″
Two Harbors, MN: 1.51″
0.2 W Culver, MN: 1.46″
Silver Bay, MN: 1.04″
French River, MN: 1.01″
Hill City, MN: 0.77″
Schroeder, MN: 0.73″
9 N Bayfield, WI: 0.71″
Chisholm-Hibbing Airport: 0.67″
Danbury, WI: 0.66″
Walker, MN: 0.58″
Lutsen, MN: 0.56″
Libby, MN: 0.55″
Duluth Airport: 0.52″
Grand Rapids, MN: 0.50″
Deer River, MN: 0.46″
Minong, WI: 0.41″
Saginaw, MN: 0.39″
Cass Lake, MN: 0.38″
Shell Lake, WI: 0.38″
Webb Lake, WI: 0.37″
Grand Marais, MN: 0.28″
Hayward, WI: 0.26″
Isabella, MN: 0.25″
Cook, MN: 0.22″
Embarrass, MN: 0.20″
Siren, WI: 0.18″
Glidden, WI: 0.13″
Ely, MN: 0.09″
Aurora, MN: 0.05″
Hurley, WI: 0.05″
International Falls, MN: 0.04″
Esko, MN: 0.03″
Poplar, WI: 0.03″
Winter, WI: 0.02″
Washburn, WI: 0.02″
Ashland, WI: 0.01″

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With only a couple days left of meteorological summer 2022 (first day of meteorological fall is September 1), let’s take a look at how we’re doing temperature wise for this summer.

Average temperatures for the summer of 2022 have been running very close to normal, generally within a degree either above normal or below normal in northeast Minnesota and northwest Wisconsin – See below.

Brainerd, MN: 69.0 F
Departure: +1.5 degrees above normal

Duluth Airport: 64.7 F
Departure: +0.1 degrees above normal

Superior, WI: 64.5 F
Departure: +0.5 degrees above normal

International Falls, MN: 64.0 F
Departure: +1.0 degree above normal

Hibbing, MN: 62.0 F
Departure: +0.6 degrees above normal

Two Harbors, MN: 60.6 F
Departure: -1.6 degrees below normal

Note: 22 days so far this summer with a high temperature of at least 80 degrees in Duluth. Normal for the summer is 25 days with a high of at least 80. It doesn’t look like will be adding anymore 80-degree days to this summer’s total, so it looks like will finish slightly below normal on the number of 80-degree days we normally get during the summer in Duluth. Last summer had a total of 46 days with a high of at least 80 in Duluth.

Thanks for reading!

Tim

Severe Thunderstorm Watch issued for parts of the Northland

4:57 PM Sunday, August 28, 2022

Severe Thunderstorm Watch has been issued for portions of northern Minnesota until 11 PM this evening. Some cities in the Northland included in this watch are International Falls, Bigfork, Grand Rapids, Cass Lake, Walker, Brainerd, Aitkin, McGregor, Pine City, Hinckley, Moose Lake, Cloquet, Duluth, Hibbing, Virginia and Ely.

Primary threats include

*Scattered damaging winds to 60 mph and isolated significant gusts to 75 mph possible.

*Scattered large hail to 1 inch in diameter and isolated very large hail events to 2 inches in diameter possible.

*A tornado or two possible.

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Strong to severe thunderstorms continue to develop over northwest Minnesota late this afternoon with further development expected farther south in west-central and central by early this evening. Storms are moving to the north/east.

Radar loop ending 4:45 PM Sunday, August 28, 2022.

Tim

Showers and thunderstorms possible this evening

2:47 PM Sunday, August 28, 2022

There is a potential for isolated to scattered strong to severe thunderstorms over all of northeast Minnesota and northwest Wisconsin this evening. The lowest risk for severe weather is over the Minnesota Arrowhead, and over eastern portions of northwest Wisconsin.

Timing is from around 6 PM to 1 AM tonight, with storms impacting western portions of the Northland first, then spreading farther east into northwest Wisconsin later this evening, most likely after 9 PM.

For Duluth — Showers and thunderstorms are possible from around 9 PM to Midnight tonight.

Primary severe weather threats for late this afternoon/evening

-Large hail to 1″ in diameter
-Damaging winds to 60 mph
-An isolated tornado threat around the Brainerd Lakes area

There is also a threat for very large hail with a few of the storms late this afternoon and early this evening over parts of western and central Minnesota.

Hail up to golf ball to hen egg size (1.75″ to 2.00″ diameter) is possible in the green area on the map.

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Storm ingredients/fuel

Plenty of low-level moisture is already in place for storms today with dew points in the mid 60s to around 70 over all of Minnesota.

Despite the widespread clouds over most of Minnesota today there is already a decent amount of instability with Mixed Layer CAPE of up to 2000 J/kg over western Minnesota, but there is also a cap in place as noted by the amount of CIN which is in the 100-250 J/kg range early this afternoon, this cap will need to erode in order for storms to develop.

Another sign of a cap is the warm 700mb temperatures of +10 to +12C covering much of western, central and southern Minnesota this afternoon.

An elevated mixed layer originating over the western High Plains is spreading a plume of steep mid-level lapse rates northeastward into the upper Midwest this afternoon with mid-level lapse rates of 7.0-8.5 C/km.

Often times will see thunderstorms form on the nose of higher Theta-E air which places northwest and west-central Minnesota in a favored zone for storm development later this afternoon since this area resides near the Theta-E ridge/bulge.

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Dynamics aloft

A potent mid and upper-level low continues to spin to the east across southeast Saskatchewan this afternoon. Forcing will increase as this system moves closer to Minnesota later today, and this should in turn weaken the cap which should lead to scattered strong to severe thunderstorm development over western Minnesota late this afternoon.

Goes-16 water vapor loop ending 1:40 PM Sunday, August 28, 2022.

Stronger flow in the mid to upper levels of the atmosphere noted in blue will spread into the upper Midwest later today as a potent trough approaches from the WNW.

As these stronger winds move into the upper Midwest will see the amount of wind shear increase to around 30-40 knots which is favorable for storm organization.

Thanks for reading!

Tim