NWS Forecast Discussion
995 FXUS63 KMPX 241754 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 1254 PM CDT Mon Aug 24 2026 .KEY MESSAGES... - Showers and thunderstorms possible tonight into Tuesday morning across central and western Minnesota. - Thunderstorms redevelop across eastern Minnesota Tuesday afternoon and will move into western Wisconsin during the evening. Isolated severe thunderstorms are possible. - Quiet second half of the work week, followed by signals for a more active weather pattern starting during the upcoming weekend. && .DISCUSSION... Issued at 1254 PM CDT Mon Aug 24 2026 Early afternoon GOES imagery captures the remnants of two convective clusters that developed across ND/northern MN and NE/IA overnight. Our forecast area remained dry between these clusters, though we have observed expansive mid-to-high clouds associated with convective debris. Visible satellite loop displays clouds thinning in the wake of the morning convection, which should allow for some more sun to filter through this afternoon and support forecast highs in the upper 70s to lower 80s. Looking upstream, a closed upper-low is captured on water vapor imagery over central Saskatchewan. The feature is forecast to move eastward across Manitoba tonight and then pivot southeastward towards Lake Superior heading into Wednesday. Associated surface low pressure will follow a similar track, which will send a cold front from west to east across the Upper Midwest. Winds have turned southerly ahead of the incoming system, which will support both temperature and moisture advection. Sensibly, it will be a mild night with lows in the mid 60s across most of the forecast area (slightly cooler into western WI) and warmer temperatures (mid 80s) follow for Tuesday`s highs. In addition, dew points will be on the rise over the next 24-hours, which will yield sufficient instability for thunderstorms ahead of the front. We`re looking at two potential rounds of convection tied to the frontal passage: 1) Late tonight into Tuesday morning, mainly across western and central MN. 2) Tuesday afternoon and evening, generally developing across far eastern MN (I-35) and moving east into western WI. 1) Late Tonight - Tuesday Morning...Thunderstorms are forecast to develop across the Dakotas this afternoon and progress eastward into northwestern MN tonight. The storms are forecast to outrun a plume of stronger instability across the Dakotas, which will result in a weakening trend by the time they advance into northwestern portions of the MPX forecast area. Forecast soundings at AXN and STC highlight this idea, with skinny elevated instability located above very stable low-levels. SPC has maintained a Slight Risk across portions of eastern ND/SD and far NW MN, where a more favorable environment for deeper convection exists. Locally, communities across far western MN are under a Marginal Risk (1/5) for the potential for an isolated instance of damaging wind or hail as the storms approach after 10 PM. This potential quickly drops-off as storms move east across central MN after midnight. 2) Tuesday Afternoon/Evening...Weakening showers and isolated thunderstorms will likely be ongoing Tuesday morning across portions of the area. While there is a level of uncertainty regarding atmospheric recovery following the morning precipitation/clouds, ongoing southwesterly flow ahead of the true surface front should aid in destabilization and yield a narrow plume of CAPEs on the order of ~1000-2000 J/kg. In addition to the instability, a jetstreak south of the upper-low will support 30-35kts of effective shear, supportive of deeper convection. One of the forecast challenges over the past few days has narrowing down areal and temporal uncertainties with regards to convective initiation. While a few "western" solutions suggest afternoon CI across portions of central to southern MN, the latest HREF/REFS ensemble consensus follows trends in ML guidance that favors CI across eastern MN. With this in mind, we`ll look for locations along and east of I-35 as having the best chance for strong to severe convection Tuesday afternoon and evening. Deeper analysis shows an environment favorable for a few isolated supercell structures across western WI, where elongated low-level curvature is present in hodographs between RNH/EAU. SPC has maintained a Marginal Risk (1/5) across much of the forecast area, which is reasonable given the overall modest convective setup with uncertainties regarding destabilization. Should surface based convection realize the potential environment, damaging winds, large hail, and a tornado or two would be possible. Convection exits the forecast area by 10 PM Tuesday evening and will be followed by a mostly quiet second half of the work week. The core of the upper-low will continue to dig southeastward into the Great Lakes Wednesday, which in turn will support breezy northwesterly flow across the Upper Midwest. We`ll run with a dry forecast for now, however we eventually may need to include isolated to scattered shower chances within the mid-level CAA regime Wednesday afternoon. Surface high pressure builds east Thursday and Friday and will bring a pleasant end to the work week with highs in the upper 70s to lower 80s along with comfortable dew points. The extended forecast features the return of a more active pattern as a series of Pacific shortwaves traverse the northern periphery of the Four Corners ridge that has dominated the weather pattern of late. The first appearance of rain and storm chances appears to arrive with the northward expansion of a mid-level thermal ridge Friday night into Saturday. Additional scattered shower/storm chances exist through the weekend, though the greatest coverage and highest chances will be later Sunday into Monday as a stronger vort max swings across the northern CONUS. Will monitor ensemble trends to better define PoP windows over the coming days, but the overall theme should support a busier weather scenario for the final few days of August and start to September. && .AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 1201 PM CDT Mon Aug 24 2026 VFR to start for all TAF sites with multiple cloud layers in place, including ceilings AOA 12kft across the coverage area. Still looking for scattered SHRA/TSRA to develop late tonight into Tue morning, starting in the eastern Dakotas and spreading eastward through the overnight hours. Confidence still fairly low on coverage of said convection, with CAMs showing multiple solutions as far as specifics but generally agree on the formation of convection through the overnight hours. Thus, have kept PROB30s going at AXN-RWF-STC-MSP, which look to have the best shot at seeing any convection overnight. Partial clearing then expected for the rest of the day tomorrow. SE to S winds at the start, with speeds generally 5-10kts (with some gusts in western MN), will continue as such thru tonight then steadily veer to SW and W during the day tomorrow. KMSP...Kept the TAF VFR throughout with multiple cloud layers, including high ceilings. However, there is a small chance of some SHRA/TSRA potentially reaching MSP around sunrise Tuesday morning. Confidence is quite low so have opted to maintain a dry TAF with this cycle but later TAFs may have the need for a precip mention should better model agreement arise. /OUTLOOK FOR KMSP/ WED...VFR. Wind NW 15G25 kts. THU...VFR. Wind NW 5-10 kts. FRI...VFR. Wind S 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...Strus AVIATION...JPC
NWS MPX Office Area Forecast Discussion