textproduct: Duluth

KEY MESSAGES

- Frost is expected again tonight across the Arrowhead and northern Wisconsin.

- Dangerous fire weather on Friday, with a Fire Weather Watch in effect for low humidity and strong wind gusts up to 35 mph.

- A prolonged active period begins this weekend, featuring a large and deep low pressure system that will bring severe thunderstorm chances and a heavy, beneficial rain footprint to Minnesota by Sunday night into Monday.

DISCUSSION

Issued at 1211 PM CDT Wed May 13 2026

High pressure dominates the Northland today, bringing abundant sunshine and pleasant temperatures in the 60s to lower 70s. North to northwest winds will remain relatively light, generally between 5 and 10 mph. However, very dry air mixing to the surface will drop afternoon relative humidity values into the 20 to 30 percent range, creating localized near-critical fire weather conditions. Tonight, the high shifts eastward, setting up another chilly night with clear skies and light winds. Temperatures will drop into the 30s across the Arrowhead and North Central Wisconsin, prompting another Frost Advisory for those areas.

A vertically stacked low pressure system tracking across the Canadian prairies will bring significant changes on Thursday. Southerly winds will increase markedly through the afternoon, gusting to 25 to 35 mph, while temperatures warm into the 70s. Moisture will accompany a warm front pushing in from the west, introducing shower and thunderstorm chances by late afternoon and evening. While instability is weak and severe storms are not expected on Thursday, a few storms could produce small hail as they track across the region overnight. There was some potential for a fire weather day on Thursday too with some model guidance going heavy handed on low RH's; however, think that high clouds moving in will suppress this as it tempers are daytime heating and thus potential to reach those lower RH values.

Friday brings a complex and highly concerning fire weather setup as a cold front clears the area. Deep atmospheric mixing behind the front will tap into strong winds aloft, driving westerly surface gusts to 30 to 40 mph. This will be paired with an influx of very dry air, plummeting relative humidity values into the teens and low 20s. A Fire Weather Watch is in effect for much of northern and central Minnesota, as these conditions will support rapid fire spread. Temperatures will peak in the 70s to near 80 degrees, especially in northwest Wisconsin.

The weather pattern turns highly active and impactful from the weekend into early next week. A deep shortwave propagating into the Intermountain West will promote a favorable southwest flow aloft across the Central US. Lee cyclogenesis into the Central Plains on Sunday will feature a deep sub-990mb low, creating a large, buoyant warm sector. This will feature a strong push of Gulf moisture into our region. This setup will provide a widespread threat for severe thunderstorms across the central states potentially reaching all the way north into NW Wisconsin. CSU severe probabilities are quite high across Wisconsin on Monday. We will see a heavy rain footprint develop by Monday, which will provide welcome and highly beneficial moisture for NE Minnesota and NW Wisconsin. Expect widespread soaking rains, strong kinematics, and localized flooding potential tied to rates and training as we head into Monday and Tuesday.

Along with the heavy precipitation and thunderstorm chances, temperatures will remain near to slightly above normal through early next week. The intense low pressure system will keep breezy conditions in the forecast through Tuesday. We will continue to monitor the exact track of the mid-May low, as its path will dictate our specific severe weather risks and the heaviest rainfall totals across the Arrowhead and northwest Wisconsin.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1231 AM CDT Thu May 14 2026

VFR conditions prevail through 21Z today. Breezy southeast turning southerly winds will occur today, strongest in north- central Minnesota. For Lake Superior shoreline terminals, expect an easterly component off the Big Lake. An approaching warm front this afternoon brings building high-based vicinity shower chances 21-03Z west to east. Have opted for mainly VCSH with a couple of hours of PROB30 at this time for all terminals except BRD where a bit higher instability in the afternoon could support an isolated thunderstorm. As the winds veer southwesterly behind the warm front a period of low-level wind shear is forecast 00-06Z this evening. The residence time of the low level jet this evening only looks to be about 3-4 hours at any terminal though. Expect a fairly well-mixed boundary layer Thursday night under the tight southerly flow regime.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 1211 PM CDT Wed May 13 2026

Light winds under 15 knots and waves of less than 2 feet are expected for western Lake Superior today. Conditions will deteriorate Thursday afternoon and night as east to southeast winds increase to 20 knots with gusts up to 25 knots. Waves will build to 4 to 6 feet along the North Shore by Thursday night. Winds will veer to the south Thursday night, then southwest on Friday, maintaining gusts of 20 to 25 knots. Small Craft Advisories will likely be needed starting Thursday afternoon.

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

FIRE WEATHER

Issued at 1211 PM CDT Wed May 13 2026

Near-critical fire weather is possible this afternoon with minimum relative humidity dropping into the 20 to 30 percent range. Northwest winds will be light at 5 to 12 mph. Thursday brings gusty south winds of 25 to 30 mph, but rain chances and increasing moisture will most likely limit the fire threat; if the clouds are later to come in than forecast, there may be near-critical issues Thursday afternoon.

Friday is the primary day of concern, featuring a Fire Weather Watch for most of our forecast area. West winds will gust up to 35 mph alongside critically dry relative humidity values dropping as low as 15 percent. Red Flag Warnings will likely be needed for Friday.

Wetting rains and thunderstorms follow for early next week.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Frost Advisory until 7 AM CDT this morning for MNZ012-020-021. Fire Weather Watch from Friday afternoon through Friday evening for MNZ010-018-019-025-026-033>038. WI...Frost Advisory until 7 AM CDT this morning for WIZ002>004-008- 009. Fire Weather Watch from Friday afternoon through Friday evening for WIZ001>004-006>008. MARINE...Frost Advisory until 7 AM CDT this morning for LSZ142.