textproduct: Twin Cities

KEY MESSAGES

- Patchy frost tonight, however cloud cover and marginal temperatures should keep it from becoming widespread.

- Quiet weather continues this week, with a chance for isolated sprinkles tomorrow afternoon.

DISCUSSION

Issued at 226 PM CDT Tue Apr 28 2026

A cool but otherwise pleasant afternoon unfolds before us as GOES satellite imagery highlights an increasing field of cloud cover expanding to our southwest with mostly cloudy skies expected by this evening for most of southern Minnesota and western Wisconsin. This is stemming from a positively tilted weak trough with some embedded shortwave energy over the northern plains, which could also produce some isolated non-accumulating sprinkles into the overnight hours over southern Minnesota where the cloud cover will be the most expansive. The forecast has generally trended cloudier and therefore a degree or two warmer compared to last night, which has resulted in a less favorable environment for frost even as temperatures still drop into the mid to upper 30s across southern MN and low to mid 30s in central MN. The entire area has yet to fully enter the growing season, which alongside the increased cloud cover within the forecast has led to the decision to forego a Frost Advisory for tonight in favor of saving those headlines for the following few nights which look to be a few degrees colder and more favorable.

The aforementioned trough is expected to pivot over southern Ontario before swinging southwards over Lake Superior, with enough CVA into southern Minnesota to produce pockets of increased cloud cover and sprinkle showers, with a non-zero chance for thunder mainly in southwest Minnesota. Temperatures aloft are below freezing and partial cloud cover will prevent complete mixing, so the weak showers may end up producing only virga as they struggle to saturate the boundary layer enough to reach the surface. Forecast soundings by the afternoon show increase low level lapse rates and a very dry layer below 750mb, with a slight inversion from 700 to 600mb due to the relatively warm temperatures aloft versus in the lower levels. With these factors combined, it seems fairly unlikely to see measurable precipitation, with the most likely chance in western WI during the afternoon but still remaining hundredths of QPF at the most.

North to northwesterly flow aloft continues throughout the rest of the week, promoting further chances for frost or even a hard freeze as cold air continues to pool over the region. The main driver behind a hard frost/freeze may end up being if we can manage to maintain even sporadic cloud cover overnight, with the slight suppression of radiational cooling key in preventing temperatures from dropping below the freezing mark. Our colder temperatures aloft finally push eastwards the 2nd half of Saturday as northwesterly flow aloft mixes with winds turning westerly and eventually southwesterly at the surface as a broad area of surface high pressure drifts through the central plains. This sets up for our next chance for legitimate rainfall, which temporally looks most likely on Monday due to lower level warm air advection/moisture advection coupled with a digging trough over the southern Great Lakes, producing a degree of frontogenesis via a tightening temperatures gradient. The synoptic forcing isn't remarkably strong, but should be enough to produce scattered showers across the area Monday afternoon which could also contain some thunder if we are able to maintain decent lower level lapse rates close to the surface warm front. For now, the axis of heaviest precipitation looks to be from central Iowa through the hard hit areas of southern Wisconsin and into northern lower Michigan, however we are far enough away where temporal/spatial differences will continue to change the forecast until we get closer.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 630 PM CDT Tue Apr 28 2026

WNW winds relax early in the period and will remain light through daybreak Wednesday. Biggest change to the 00z TAFs was to include gusts between 20-25kts at all terminals from late morning through the afternoon period tomorrow. Forecast soundings show a favorable mixing signal within the WNW flow, so the boost was warranted. Otherwise VFR with high clouds moving across the region tonight. There is a chance for a few sprinkles/showers within the northwesterly flow tomorrow, however little if any measurable precipitation is expected. Should have a diurnal Cu field ~5-7k feet through the afternoon.

KMSP...No additional concerns.

/OUTLOOK FOR KMSP/ THU-SAT...VFR. Wind NW 5-10kts. SUN...MVFR ceilings psbl. Slgt chc -SHRA. Wind NW 5-10kts.

MPX WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None.