486 FXUS63 KMPX 092036 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 336 PM CDT Wed Jul 9 2025 .KEY MESSAGES... - Dry and mild tonight, with the chance of showers and thunderstorms across southwestern Minnesota overnight. - Marginal Risk (Level 1 of 5) for strong to severe thunderstorms Thursday afternoon into early Friday. - Widespread soaking rain and storms Friday through Friday Night. - Warm and mainly dry Saturday-Monday, then the next system to bring organized rain/storms arrives Tuesday-Wednesday. && .DISCUSSION... Issued at 334 PM CDT Wed Jul 9 2025 Surface analysis this afternoon shows high pressure centered over the western Great Lakes, encompassing MN/WI, while a surface low over eastern Saskatchewan province has an associated warm front extending south across the Dakotas and into the mid- Mississippi River Valley. Multiple surface lows dot southwest Canada, linked by weak frontal boundaries, while high pressure generally prevails over the Rockies to west coast. Aloft, a deep high pressure ridge sits centered over the Four Corners region with a ridge axis extending NE over the Northern Plains into Manitoba province. In addition, a deep upper level low sits over northern Alberta province with a couple notable shortwave trough axes rotating around the main low. These shortwaves will become the focus for our more active weather Thursday-Friday. The area of surface high pressure will slowly shift to the east over the next 24 hours, owing to the ridge axis from the desert southwest nudging it to the east while the over southwestern ridge flattens. Increasing isentropic lift in advance of the warm front will spark off a few showers/thunderstorms in western MN late tonight into Thursday morning, nothing of consequence but a few heavier dumping showers are possible given the moist environment across the region (PWAT 1.00"-1.25"). This will be in conjunction with minor buckling in the H5 flow, creating weak shortwave troughs which will drift through the Dakotas into MN/WI late tonight through tomorrow. Have kept PoPs in the 20-30% range due to the expected isolated to scattered nature of the distribution of precipitation. The bigger issue becomes the deep western CONUS low for Thursday night as it thrusts a potent shortwave trough axis southeast through the PacNW during the day Thursday, moving through the Northern Rockies Thursday night into Friday morning. At the surface, the cold front associated with the Saskatchewan low (which will move into southwest Ontario province by Friday morning, will shift southeast and extend from northern MN southwestward through the Dakotas. Along this front, a secondary low pressure center will develop over eastern NE into western IA, essentially helping advect moisture of Pacific/Gulf origins and low level convergence into the Upper Midwest. The confluence of these synoptic features aloft and at the surface along with the plentiful moisture will spell fairly persistent rainfall early morning Friday through Friday evening. Rainfall totals will likely exceed 1" from southern-eastern MN into western WI. The shortwave trough aloft which will swing across the area Friday night into Saturday will take on a more negative tilt during the night, which may not only aid heavy rain potential but potentially also severe weather development. There is a broadly- spread Marginal (Level 1 of 5) Risk of severe thunderstorms for mainly late Thursday through Friday. Still too much uncertainty to determine the placement with such broad moisture and lift mechanisms across the region, but the placement of the LLJ will determine if/where an MCS may develop and progress across the area. Those details will still be hashed out over the next 24-36 hours by SPC. Once past this relatively heavier rain event, dry weather is expected for the Saturday-Monday timeframe as surface high pressure of western Canadian origin along with a broad ridge axis glides across the region. The next system of consequence will arrive Tuesday as another western Canadian upper level low takes a similar progression, drops a potent upper level trough axis southeast through the PacNW region, but this next system becomes much more wound-up aloft. A deep H5 low looks to develop over south-central Canada to aid in cyclogenesis of a low off WY/SD, potentially bringing another round of widespread rain Tuesday into Tuesday night. As for temperatures, highs look to generally remain in the upper 70s to mid 80s for the end of this week through the start of next week, but it`s not until after the passage of the system for the middle of next week that a cooling trend may well be upon us. Models indicate that starting next week Wednesday, highs will hold in the 70s area- wide while lows drop to the 50s area-wide. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1235 PM CDT Wed Jul 9 2025 Southeasterly winds AOB 10 kts through the afternoon, with diurnal CU field developing around ~5kt feet. It`s possible the western MN will need -SHRA/TS mention late tonight in association with storms that are forecast to develop over the Plains. For now, have included PROB30s at AXN, MKT, and RWF for the morning convection. Confidence in impact to terminals is currently too low to go prevailing. KMSP...Slight chance, not even PROB30 worthy, for a shower in the morning hours at MSP. Did not include this in the TAF for confidence is low in impacts. For afternoon showers and storms, went the PROB30 route due to low confidence in where storms will bubble up and if they will impact the terminal. /OUTLOOK FOR KMSP/ THU...VFR. SHRA/TSRA likely late night. Wind S 10-15kts. FRI...SHRA/TSRA likely. Wind SW 5-10kts bcmg WNW 10-15kts. SAT...VFR. Wind NW 10-15 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...JPC AVIATION...PV