textproduct: Duluth

KEY MESSAGES

- Thunderstorms are possible this afternoon and evening. Isolated strong to severe storms may produce damaging winds or large hail. Marginal severe outlook into this evening (level 1 out of 5).

- Lingering showers and thunderstorms are possible Friday. - Cooler and quieter conditions for the weekend.

- Next chance for showers and storms after Friday is late Monday into Tuesday.

DISCUSSION

Issued at 128 PM CDT Thu Jul 30 2026

A mixed bag of conditions out there this afternoon. We have partial sunshine for most places with some haze from smoke aloft. Around the International Border, we have had some thunderstorms as well. Storms have been fueled by strong warm air advection and quite a bit of instability in place through the morning. There is also some cyclonic vorticity advection aloft. Once storms formed, it looked like their movement was based partially on where instability was and possibly storms developing along their outflow boundaries. The Arrowhead saw a quick round of potentially severe storms with radar signatures suggesting that there could have been some ~60 mph downburst wind gusts.

For this afternoon and evening, the main concern is more potential for thunderstorms. Vertical shear is expected to decrease, and thus the threat for hail will likely be limited to initial updrafts for short duration. Following that, storms may rain on themselves with the lack of shear, and then the primary threat with any storms will be damaging downburst winds. The predictability of where and when storms may develop this afternoon is rather low, but the synoptic forcing is not expected to change too much in placement, so northeast Minnesota will see the highest chance for any severe storms, and that's where SPC maintains a marginal risk for severe storms.

Low pressure will pass by to our south tonight, bringing plenty of rain to central/southern Minnesota, mainly along/south of I-94. Up here, rainfall amounts are expected to be less dramatic as a whole with less synoptic forcing and PWAT (though PWAT will actually still be high up here around 1.5-2.0"). Widespread amounts will likely hover around a quarter of an inch, but with PWATs being pretty high, any thunderstorms will have the capability to produce locally high amounts over an inch. CAPE should gradually decrease overnight, so the severe threat should be limited to this evening. Flooding threat overnight is non- zero, but it's expected to be pretty isolated and only in any places where any persistent storms may develop (which isn't a guarantee).

Expect rain to slowly move east on Friday as a cold front passes through. We will probably deal with lingering thunderstorms in northwest Wisconsin into the afternoon, and possibly along the North Shore. After the rain exits, high pressure is expected to dominate through the weekend. Temperatures will cool down a bit and we are expected to see some pleasant weather overall. Smoke conditions are likely to improve as well as we get more northerly flow and less influence from wildfire smoke origins out west.

Flow returns to south/southwesterly Sunday into Sunday night, and we should see warmer temperatures on Monday with highs in the 80s. There's pretty good agreement on an upper level trough with an attendant cold front swinging through around Monday night. At this time, convective parameters as a whole don't look too impressive, but we'll have to keep an eye out for at least a small chance for a nocturnal squall line that could produce some gusty winds. We will probably return again to more seasonable temperatures Tuesday into Wednesday with quieter weather, then maybe briefly warmer Thursday with another cold front going into Friday.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1236 PM CDT Thu Jul 30 2026

Areas of breezy winds this afternoon that should become light after about 3-5 hours. Otherwise, the biggest challenge will be timing out potential showers and thunderstorms. At this time, confidence is low for when redevelopment may take place, but we could see more storms late this afternoon and evening around INL, potentially affecting other terminals a little later. Most likely, not every terminal will be affected by thunder, but there is at least low probability for all except possibly HYR. Showers and storms will make their way through the Minnesota terminals tonight, lingering through the period at HYR. Any storms could produce brief MVFR to IFR visibilities. Otherwise, predominantly VFR conditions are expected through the period.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 128 PM CDT Thu Jul 30 2026

The main marine concern for this afternoon and tonight will be isolated thunderstorm potential. There's low confidence on timing and placement of storms, but near the North Shore is most likely. A stray strong to severe storm capable of producing wind gusts up to 40-50 kt can't be ruled out, but these are expected to be pretty few and far between. General rain showers are possible tonight into Friday as well. Otherwise, winds remain generally light from the southwest tonight and into Saturday early morning (becoming northeast Saturday). Another concern for tonight is some patchy dense fog that could develop. Areas of fog along the North Shore this afternoon look to have become spotty, so the current Dense Fog Advisory currently in effect is expected to be allowed to expire this afternoon.

For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt.

FIRE WEATHER

Issued at 128 PM CDT Thu Jul 30 2026

Showers and thunderstorms are expected this evening into Friday. Coverage will be spotty, and while most places will likely pick up a tenth of an inch or two, some places may see very little, and others that see some thunderstorms develop could locally see an inch or more. The best chance for any higher accumulations will be from roughly International Falls to the Brainerd Lakes where scattered storms may develop this afternoon into this evening. Isolated strong to severe storms could contain some damaging wind gusts and perhaps brief large hail.

A cold front will accompany rain/storm chances tonight, causing a wind shift to northerly into Friday and north to northeasterly into Saturday. Winds return to southerly Sunday into Monday, and some gusts to 20 mph are possible with that. Min RH Saturday through Monday will be a little lower with high pressure dominant. 40-50% RH with a few places perhaps falling to 35% can be expected. There may be pockets of places where fire weather conditions could be a little elevated.

Another cold front could bring some rain and thunder Monday night.

See the Fire Weather Forecast product for a more thorough breakdown of fire weather conditions.

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...Dense Fog Advisory until 4 PM CDT this afternoon for LSZ140>142.