textproduct: Duluth

KEY MESSAGES

- Another round of strong to severe storms Monday with timing most likely being overnight once again. Threats are hail, winds, and tornadoes. Heavy rainfall leading to localized flooding will also be possible.

- Colder air returns Tuesday and Wednesday, a Freeze Warning may be needed for Tuesday night.

- Next chance for precipitation will be this weekend.

UPDATE

Issued at 246 AM CDT Mon May 18 2026

Early this morning, the initial wave of storms moving through the Northland has weakened and these storms are no longer expected to be severe. However, general showers and standard thunderstorms will continue rolling through the region into the mid to late morning hours. As we head into this afternoon and evening, another round of showers and storms is possible, primarily focusing on the northwest Wisconsin area. Cloud cover and cooler temperatures are expected to keep a firm inversion in place for most of the area. This inversion will heavily limit the potential for tornadoes north of where the environment destabilizes, mainly across central Wisconsin. The potential for large hail and damaging winds remains a threat with the strongest storms. Additionally, flooding still remains a concern due to the potential for training storms along the cold front. Fortunately, the front seems to move fast enough that any flooding issues will remain isolated.

DISCUSSION

Issued at 224 PM CDT Sun May 17 2026

Current Conditions/Today:

Strong easterly flow envelops the region today with cloud cover increasing. Radar shows areas of weak echoes across western MN and NW WI. Reports thus far have not yielded much in way of rainfall yet and will likely still take some time for this rain to make it to the surface. Especially with how dry the morning sounding was for INL. We are seeing some noticeable areas of isentropic ascent ahead of the approaching warm front though. These surges are over both the Red River Valley and into NW WI which will likely be our best chances for this initial batch of rain before the main system ramps up later tonight. That being said rain chances through the afternoon are 20-30%.

Tonight:

The main show is expected to arrive later tonight. An inverted trough moving across the Northern Plains will transition into the primary low pressure system with a strong cold front trailing into the Central Plains. Severe storms are expected to develop in SW SD this afternoon. Through the evening hours the low pressure will advance NE towards NW WI. A strong low level jet will help to sustain the ongoing convection and drive the activity into the Northland. Storm mode as it moves into our region will be linear with damaging winds being the primary hazard. Large hail can't be ruled out as well but the more favorable lapse rates don't line up well with the current progression of the storms. Tornado threat also looks low as surface based convection tied to the cold front looks to stay south of the region. Overall timing for the worst conditions look to move in after 9PM and exit to the east after 4AM. Primary impact areas align with where SPC has their severe weather outlook. Clipping the Brainerd Lakes area with NW WI mostly likely seeing the lion's share of the activity. Rain totals with the main band of storms could range from 0.50-1.00" with PWATs over 1.25" some storms could produce totals over 1.50"

Monday:

Monday's set up will heavily depend on the progression of the previous nights frontal boundary. The 12Z suite of deterministic guidance is in decent agreement with stalling out the frontal boundary over NW WI. SPC severe outlook has the marginal risk draped across NW WI and sliding southwest into southern MN. This outline essentially highlights the most likely warm sector in which we have potential for the atmosphere to reload on instability for strong to severe storms once again. Areas west of this could still see some rain development as a mid level trough pivots across the Northern Plains, but thunderstorm potential is not as great. High res guidance is once again suggesting a late night threat with linear storm mode. With the cold front being much closer to the region some storms may become tied to the surface allowing for some surface vorticity ingestion. All modes of severe will be in play with QLCS tornadoes not out of the question. Activity may ramp up as early as 7PM with some discrete cells forming in the warm sector initially. The linear storm is currently projected to move in after 9PM and out of the region by 3AM with some lingering showers. Additionally, localized flooding may become a concern. Heavy rainfall rates may impact areas already inundated from the previous round of storms.

Tuesday/Wednesday:

High pressure will start to move in from the west on Tuesday with highs in the 40s and 50s. Remnant moisture from the departing system with cyclonic flow aloft could still lead to some scattered showers. Tuesday night will sport some very chilly temperatures with a Freezing Warning likely being needed for most of the Northland. Temperatures rebound a bit on Wednesday as surface high pressure saunters off to the east. Highs will climb back into the 50s and 60s.

End of the Work Week:

With the departure of high pressure Thursday will see southerly flow returning to the Northland. Highs continue to trend back up with widespread afternoon temps expected to reach the 60s. Cluster analysis shows an upper level trough moving out of the Rockies once again which will prompt increased chances for precipitation. At this time we are carrying 20-30% chance of rain to end the week.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1222 AM CDT Mon May 18 2026

Blend of IFR and VFR for now with east winds decreasing and eventually turning light north. A complex of storms will move NW WI this morning. Thinking KHYR will be the most impacted though believe there will be the typical spring return flow that brings LIFR conditions into KDLH in the post-complex air mass with onshore easterly flow. Thinking this will last into tomorrow morning with low confidence on its occurrence due to the complex mainly dissolving in the dry air mass, so it may just act to saturate the lower levels - maybe enough to form the low stratus and fog. Another round of storms is expected this evening.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 246 AM CDT Mon May 18 2026

Small Craft Advisories remain in effect for the nearshore waters this morning due to elevated northeast winds and waves. Northeast winds will ramp up again late tonight, bringing gusts up to 25 knots and building waves to 4 to 8 feet. Winds will eventually shift to the northwest by Tuesday afternoon, allowing waves to gradually subside.

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

FIRE WEATHER

Issued at 246 AM CDT Mon May 18 2026

Scattered rain showers and thunderstorms will limit fire weather concerns through the early part of the week. A high pressure returns for the mid week and low minimum RHs in the 30s return once again. Gusty winds will subside briefly during the day today, but will increase once again out of the north to northwest overnight. These winds will continue into Tuesday, with sustained winds to 15 mph and gusts to 25 mph.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...Small Craft Advisory until 10 AM CDT this morning for LSZ140>148-150.