Marine Weather and Tide Forecast for Pepin, WI

DISCUSSION
Issued at 310 PM CDT Wed May 13 2026

It's a beautiful May afternoon across the forecast area, with mostly sunny skies and temperatures warming into the low to mid 70s.
Satellite shows mid-level Cu over WI, along with more recent blossoming Cu across western MN in response to diurnal mixing.
Speaking of which, the efficient mixing has supported wind gusts generally between 15-25 mph. Cu will dissipate and winds will relax this evening.

Center of an expansive area of high pressure will build east towards the Great Lakes tomorrow. To the northwest, a negatively tilted shortwave trough and associated ~980mb surface low will pivot over southern Canada. This evolution will result in a channel of strong southwesterly winds (850mb LLJ of ~40-50 kts) setting up across the eastern Dakotas and western MN. Surface winds are forecast to sustain between 20-30 mph and gust between 35-45 mph across much of western MN tomorrow. There will likely be a line of pre-frontal/warm sector showers tomorrow which combined with cloud cover may limit RH's from completely plummeting (Our grids show Min RH's around 30 percent tomorrow afternoon). Still, with the recent dryness, near- critical RH's, and strong winds we collaborated with western neighbors to issue a Red Flag Warning from 10AM-7PM. In addition to fire weather, the strong southerly winds will combine with ongoing dry conditions to support another potential round of blowing dust (though this time the wind vector is from the opposite direction). We'll have to wait for observational trends tomorrow before hoisting a blowing dust headline, but it's another piece of the forecast that bears watching. As far as the pre-frontal round of showers, CAMs are in decent agreement with showing a line of precipitation moving east across south central MN into western WI tomorrow afternoon and evening. It's possible that the CAMs offer more bark than actual bite when it comes to the precipitation rates within these showers, as forecast soundings reveal a wedge of very dry air below 7-8k feet. A short 2-3 hour window of deeper saturation can be found above this level. In addition, there is little if an instability to note (perhaps a couple hundred joules of MUCAPE), associated with the elevated showers so the overall threat of thunder appears to be low and fairly isolated. Still, with steep low- level lapse rates it's possible that enhanced wind gusts may reach the surface beneath the showers, which will be possible well to the east of the main LLJ/synoptic flow axis.

An eastward moving cold front will pass late Thursday/early Friday and turn the winds westerly for the last day of the work week.
Should be another breezy day, with sustained winds of 15-25 mph and gusts 25-35 mph (strongest across western MN). Additionally, RH's are forecast to be much lower on Friday (say between 15-20 percent during peak heating) as a result of a surface highs making a run into the mid to upper 80s (a few spots may hit 90 degrees!). The anticipated hot, windy, and very dry post-frontal conditions have prompted increased concern on more widespread fire weather conditions, so have collaborated with neighbors to expand the Fire Weather Watch to include all of western MN, central MN, and Polk, Barron, and Rusk counties in western WI. The southern cut-off of the Fire Weather Watch signals the dividing line where the Spring green-up is well underway, so the threat of rapid fire spread is not as high (despite similar hot, dry, and breezy conditions). Fire weather concerns should not be as high on Saturday, as winds are forecast to be lighter between weather systems. Highs take a step back into the upper 70s/lower 80s Saturday afternoon.

The forecast takes on a much different (wetter) look from Sunday onward. Deep western troughing will send a series of shortwaves northeast within large scale southwesterly flow positioned from the central Plains into the Upper Midwest. Warm/moisture advection will increase ahead of the initial shortwave set to spawn an expansive shield of precipitation across the north central CONUS Sunday. The signals for widespread precipitation associated with the large scale ascent/initial slug of moisture moving north is fairly high and has already pushed NBM's PoPs into the 80-90 percent category for the second half of the weekend. A secondary, stronger shortwave is set to take on a negative tilt as it advances northeast into the Dakotas on Monday. Guidance advertises a warm sector southeast of this feature from Iowa to eastern MN to central WI, which will be a region favored for possible strong to severe thunderstorms. Pattern recognition would suggest that Sunday is more of classic widespread heavy precipitation setup and Monday serves as the better opportunity for severe thunderstorms ahead of a passing cold front. That being said, we'll have to wait for higher confidence in surface low/frontal placement prior to locking into greater details.
WPC's latest forecast is consistent with ensemble means of 1-2"+ of rainfall across much of the Upper Midwest. In addition, both SPC and CSU-machine learning guidance have highlighted portions of the area for severe weather potential (southern MN on Sunday, eastern MN/western WI on Monday where SPC has introduced 15 percent risk areas in the Day 5/6 outlooks).

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
Issued at 552 PM CDT Wed May 13 2026

Diurnal cumulus from this afternoon over RNH and EAU will dissipate early this evening. Clear skies expected tonight but high and then eventual mid-level clouds build in from west to east during Thursday. Cigs could lower to near 6000 feet in the afternoon over MN. Added PROB30s at most terminals (except EAU)
Thursday afternoon for a possible scattered line of -SHRA moving east thru the area. Heavier showers could result in visibilities briefly visiting MVFR. Northerly winds slow and quickly turn southeasterly during this evening. Speeds will increase tonight through Thursday morning with winds maximizing and turning more southerly late morning through the afternoon.
Strongest values are expected in western MN where sustained speeds will range from 20-25 knots while gusts reach 30-35 knots. Winds decrease to the east with WI terminals having gusts to 20 knots. Southerly LLWS of 45 knots is expected over AXN from 12-14z Thursday.

KMSP...Sustained south-southeasterly winds will reach around 15-17 knots with gusts of 25-30 knots late Thursday morning through Thursday evening. Kept PROB30 for -SHRA late Thursday afternoon. Southerly LLWS of 45 knots also looks likely Thursday evening.

/OUTLOOK FOR KMSP/ FRI...VFR. Wind SW to W 15-20G30 kts.
SAT...VFR. Wind NW 5-10 kts.
SUN.. MVFR/-SHRA/-TSRA, chc IFR. Wind SE 10-15G30kts.

MPX WATCHES/WARNINGS/ADVISORIES
MN...Red Flag Warning from 10 AM to 7 PM CDT Thursday for Brown- Chippewa-Douglas-Kandiyohi-Lac Qui Parle-Martin-Pope- Redwood-Renville-Stevens-Swift-Watonwan-Yellow Medicine.
Fire Weather Watch from Friday morning through Friday evening for Benton-Chippewa-Chisago-Douglas-Isanti-Kanabec- Kandiyohi-Lac Qui Parle-McLeod-Meeker-Mille Lacs-Morrison- Pope-Redwood-Renville-Sherburne-Stearns-Stevens-Swift- Todd-Wright-Yellow Medicine.
WI...Fire Weather Watch from Friday afternoon through Friday evening for Barron-Polk-Rusk.