Marine Weather and Tide Forecast for Lake City, MN

UPDATE
Issued at 850 PM CDT Tue May 20 2025

Evening forecast update reflects tightening of the highest PoPs over western WI/central MN as bands of steady rain continue to lift north. While the mosaic has become less active across south central MN, still have maintained slight chance to chance PoPs in the short term given the continued flow of moisture streaming north which is reflected by drizzle/fog. CAMs continue to display steady precip filling back in along the I-94 corridor as we head towards daybreak, so have not made any major adjustments to the going forecast heading into tomorrow.

DISCUSSION
Issued at 351 PM CDT Tue May 20 2025 It's a real soaker out there today as we find ourselves sandwiched between a low pressure over Iowa and a Hudson High. We find ourselves within the baroclinic zone between the dry Hudson high and the warm/higher moisture low over Iowa. There's a persistent feed of moisture from the east to the west from southern Michigan toward eastern North Dakota. This baroclinic zone aloft will be affiliated with an inverted trough at the surface and these two forcing features are expected to budge north slightly tonight, then slowly slide back south through the day on Wednesday. This means for the I- 94 corridor from the Twin Cities to Alexandria, it will continue to rain through the day on Wednesday, with the rain possibly not ending in the Twin Cities until close to midnight Wednesday night. Starting tonight, this rain may end up jumping between more drizzle and rain than a steady rain, but wet conditions will continue through the day on Wednesday. Based on what we've seen so far, along with the additional 0.5" to 1" expected through Wednesday, we're going to end up with 2"-4" of rainfall in our entire area southwest of an Eau Claire to Rice Lake line. Within this, we're quickly heading to an area centered over Sibley county (between New Ulm and the Twin Cities) where rainfall amounts will top 4". For reference, MSP averages 3.91" of rain in May, so we're going to have some places that end up getting more than a typical May's worth of precipitation between Monday and Wednesday night.

One reason this system has stalled out and will continue to send us rain through Wednesday is we actually have yet another rex block pattern forming this afternoon, with a ridge beginning to crest into northern Canada directly to the north of the low down over us. This blocking pattern will be with us through the upcoming holiday weekend, with our current system eventually developing into a sprawling cutoff h5 low centered over the Great Lakes. We will be to the west of the low and in an area that's favored for surface high pressure. This high pressure will hold temperatures back to having lows in the 40s and highs in the 60s (so 5-10 degrees below normal)
through the holiday weekend. Where there continues to be more uncertainty is with rain chances through the weekend. Given the low level air source being a dry Canadian high, it's hard to see there being much precip chances this weekend and we see a mainly diurnal pattern to PoPs from the NBM through the weekend that are 10-20% overnight and in the 20s and 30s in the afternoon. Certainly the rain doesn't look to crash your holiday weekend plans, but for Memorial Day standards, it will be chilly sweater weather for most of it.

Next week, the ridge does start to flatten out, with warm air able to make it back this far north, with highs in the 70s making a return after Memorial Day.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
Issued at 1216 AM CDT Wed May 21 2025

IFR/LIFR conditions expected area-wide through at least Wednesday morning as cigs under 1000 feet, mist, and rain showers persist. Current radar shows rain showers filling in again across eastern MN and WI. This trend should continue through Wednesday morning with a gradual expansion of rain westward late morning into the afternoon along a northwest to southeast stationary front. Rain should then dissipate from north to south during Wednesday evening. Expect visibilities to hang somewhere between 3-5sm from mist and showers. Also, not optimistic about cigs and cloud cover improving quickly. Kept most terminals south of AXN, STC, and RNH only improving to MVFR by the end of the TAF period. East-northeasterly winds of 7-10 knots expected at most terminals through Wednesday afternoon before shifting northerly and slowing. However, RWF and MKT will be south of the stationary front and their winds will be northwesterly during Wednesday.

KMSP...Showers and IFR cigs look likely until Wednesday evening before cigs begin to lift and rain tapers off. Thinking improvement to MVFR occurs around 03Z Thursday and then VFR by 06Z as clouds lift and break apart. East-northeasterly winds of 7-10 knots expected into Wednesday afternoon before winds gradually turn northerly and slow to near 5 knots.

/OUTLOOK FOR KMSP/ THU...VFR. Wind N 10-15kts.
FRI...VFR. Wind NE 5-10kts.
SAT...VFR. Wind E 5-10kts.

MPX WATCHES/WARNINGS/ADVISORIES
MN...None.
WI...None.