textproduct: Duluth

KEY MESSAGES

- Critical to Near-critical fire weather conditions are expected today. A Red Flag Warning has been issued for today around the Brainerd Lakes due to breezy southerly winds and critically dry relative humidity.

- Strong to severe thunderstorms may be possible on Thursday afternoon and evening as a cold front moves through the area. A Marginal Risk is in effect for much of the area.

- Cooler, yet near seasonal normals, temperatures are expected to move in on Friday and persist into early next week with additional chances for rain.

UPDATE

Issued at 346 AM CDT Wed Apr 22 2026

The main concern today is the fire weather conditions with the very dry airmass lingering over the area. Yesterday, dewpoints were in the teens and low 20s for much of the afternoon, producing minimum RH values down around 15 percent. While we should not be as dry as yesterday with southerly winds beginning to push moisture back into the region, it will still be critically dry, and with the stronger winds today compared to yesterday, fires may spread rapidly. Model guidance, as is fairly typical this time of year is too moist with dewpoint and/or RH values, and tends to advect the moisture into the Northland too quickly. In fact, just yesterday the 21z dewpoint was well below the 5th percentile of the NBM, and Monday it was down around the 10th percentile of the NBM. Needless to say, I have gone with pretty dry values, though not quite to the 10th percentile. There is a steep gradient across the forecast area, with dewpoints rising to near 40 around Brainerd, but remaining in the 20s for the Arrowhead. Anyway, with the very dry conditions and increased winds for today, we have decided to upgrade the Fire Weather Watch to a Red Flag Warning. Also, considering how dry it will still be for any of our inland areas, there will be a Special Weather Statement for all or parts of our other MN counties. Lake winds will be east to northeast and breezy today, causing areas near Lake Superior to not only be 10 to 15 degrees cooler than inland areas, but also much more humid.

The next timeframe of concern is Thursday and Thursday evening. After a very warm day, scattered showers and thunderstorms are expected to develop by Thursday afternoon and continue into the evening hours. There was a notable shift in the CAM models to the east for the position of the cold front during the day on Thursday. This shift has now pushed the convective initiation to over the Northland as opposed to west of us, which we were seeing yesterday. Favorable atmospheric dynamics and instability will support the potential for a few strong to severe thunderstorms. The primary hazards with any severe storms that develop will be large hail and damaging wind gusts. The shift in timing noted above pushes the timing a little earlier, but more centered over the area. The Storm Prediction Center has all of the CWA in a Marginal Risk for Thursday, with a Slight to our south.

DISCUSSION

Issued at 258 PM CDT Tue Apr 21 2026

Fire weather concerns today through Wednesday:

Near-critical fire weather conditions continue today as a very dry airmass lingers over the CWA. Latest surface analysis reveals high pressure over northern MN, which has allowed for dry air advection to occur into the CWA from Ontario. Widespread min RH values below 20% are expected this afternoon due to this dry air mass and moderately deep mixing to around 5,000 feet. Fortunately, northerly winds have been relatively light today, especially in comparison to the breezy southerly winds yesterday. Therefore, a Special Weather Statement for near-critical fire weather conditions remains in effect today in northeast MN, where dry fuels are of particular concern.

A 500mb ridge, currently centered over the High Plains, will be shifting eastward into the CWA tomorrow ahead of an approaching deep trough. With winds shifting to the south on Wednesday, this will allow for WAA to occur and increase high temps into the 70s to around 80 across much of the area. The exception to these 70+ degree temps will be along the North Shore where cool air moving inland from Lake Superior will keep highs tomorrow around 10-15 degrees cooler than locations farther inland in the Arrowhead.

In addition to warm temperatures, critically dry RH as low as 20% is forecast for tomorrow. There is some degree of uncertainty tomorrow in terms of RH, notably how far north moisture will advect with the southerly flow during peak diurnal heating. In the forecast update this afternoon, opted to err on the drier side given the trend from the past couple days. One change for Wednesday will be stronger winds compared to today in north- central MN, mainly around the Brainerd Lakes area. Wind gusts up to 25 mph will be possible, most likely starting after 18z and remaining elevated into Wednesday night.

Due to the combination of critically dry RH, breezy winds, and receptive fuels, a Fire Weather Watch was issued for Wednesday from 12 PM to 8 PM in the Brainerd Lakes area, including Itasca and Aitkin Counties. If recent model trends continue and moisture advection remains fairly marginal during the daytime hours, an upgrade to a Red Flag Warning will likely be needed. Use caution with fire and follow any burn restrictions.

Severe Weather Potential and Change in Pattern:

Wednesday night will begin a change in pattern from warm and dry conditions to wetter and cooler. A deep, vertically-stacked surface low will be arriving into the Midwest late Wednesday into Thursday as the aforementioned deep trough propagates east. The first round of convection associated with this system is forecast to arrive Wednesday evening along a lifting warm front. Since there will likely be a sizable dry layer lingering in the low-levels, precipitation amounts will be limited and much of this will likely fall as virga. Instability appears to be favorable along this warm front, with some guidance suggesting MUCAPE in excess of 500mb. However, model soundings show that any potential storms will be elevated to the point where convective initiation will be difficult. The 12z HREF composite reflectivity members reflect this well, with convection being limited across the CWA.

The time period of greater concern for any strong to severe thunderstorms will be Thursday afternoon and evening as the cold front associated with the vertically-stacked low sweeps through the CWA. Conditions in our neck of the woods continue to appear marginal at best, with the arrival of best instability occurring around/after peak diurnal heating. Convective initiation is most likely to occur along the front to our west and propagate into our CWA late on Thursday. CSU machine learning probs continue to show the greatest potential for severe weather to the west and south of the CWA. The Storm Prediction Center has much of the CWA in a Marginal Risk for Thursday, which is in line with the current assessment of marginally favorable bulk shear and instability.

Following the cold frontal passage on Thursday night, high temps are forecast to be around 10-15 degrees cooler on Friday. These cooler, yet seasonable, temps are likely to persist into the weekend and early next week with additional chances for rain on Friday and early next week.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1213 AM CDT Wed Apr 22 2026

VFR conditions will prevail through the period. Clouds will start to increase Wednesday afternoon, but will be above 10kft. Light and variable winds overnight will give way to breezy southeasterly winds starting around 16z Wednesday morning. Gusts to 15 to 20 knots are expected, with the strongest winds of around 23kts for KBRD. After 02z, strong south winds aloft will produce LLWS for the terminals of up to 40kts.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 346 AM CDT Wed Apr 22 2026

Surface high pressure pushes east this morning, with east to northeasterly winds increasing today, to gust into the 15 to 20 knot range for several hours this evening. The next period for potential hazardous conditions for smaller vessels is Thursday through Friday. East to northeast winds increase on Thursday, leading to building waves causing building waves along the North Shore. Winds back into the north and then northwest late Thursday night into Friday. There will also be potential for strong thunderstorms on Thursday and Thursday night.

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

FIRE WEATHER

Issued at 346 AM CDT Wed Apr 22 2026

Critical to Near Critical fire weather conditions to affect the area once again today. Minimum RH values will drop into the 15 to 20 percent range with southerly wind gusts of 20 to 30 mph for the areas around the Brainerd Lakes, where a Red Flag Warning has been issued for today. Winds will be lighter for areas farther northeast, but just as dry, so we have issued a Special Weather Statement for most of northeast MN.

Widespread showers with thunderstorms arrive on Thursday afternoon and evening along a cold front, which will likely bring a wetting rain across the region. A few storms may become strong to severe, with gusty and erratic winds and the potential for large hail. Expect cooler conditions on Friday into the weekend with additional chances for rain.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Red Flag Warning from noon today to 8 PM CDT this evening for MNZ018-025-026-033>036. WI...None. MARINE...None.