Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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320 FXUS63 KMPX 032006 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 306 PM CDT Mon Jun 3 2024 .KEY MESSAGES... - Scattered showers and thunderstorms across western Wisconsin this afternoon. - A line of thunderstorms will move through the area tomorrow afternoon & evening. Isolated damaging winds & a tornado or two are possible, primarily across eastern Minnesota & western Wisconsin. Widespread rainfall amounts of 0.5-1" could exacerbate ongoing flooding, especially where locally higher amounts occur. - Trending drier towards the end of the week & through next week. && .DISCUSSION... Issued at 232 PM CDT Mon Jun 3 2024 Showers and thunderstorms have developed across western Wisconsin along a lingering frontal boundary left over from last night`s precipitation. Deep shear values on the order of 20-25 kts mean storms will relatively short-lived & pop-up in nature, but CAPE values of 1500-2000 J/kg mean a few stronger updrafts capable of small hail & gusty winds are possible. This activity will wane towards sunset, with a relatively clear & calm night expected. Slight warm advection will help to limit fog development overnight, but patchy dense fog still looks possible across low-lying areas of eastern Minnesota & western Wisconsin. A cold front will move through the region during the on Tuesday, with an elongated pressure trough stretching back to a fairly deep parent surface low over the southern Canadian prairies. This front is forecast to move through our area during the peak heating of the afternoon, and forecast CAPE shows ample instability of around 2000 J/kg ahead of the front across eastern minnesota & western Wisconsin. However, the best forcing & deep shear will remain behind the frontal boundary and any showers & thunderstorms, and any shear along that storms will be able to utilize will be fairly weak & nearly unidirectional along the front. This would suggest that storms that initially develop during the early afternoon across eastern SD/western MN would quickly merge & become linear, with the line of showers and thunderstorms progressing eastwards across Minnesota through the afternoon & during the evening across western Wisconsin. Various high-resolution models show pockets of updraft helicity tracks & stronger reflectivity cores within the line, meaning isolated damaging wind gusts and a tornado or two are possible if a few stronger cells are able to modify their local environment & increase shear values via mergers & remnant boundaries. Heavy rain is expected with the thunderstorms during the afternoon & evening, but the progressive nature of the front should limit how long it rains over any given area. Widespread precipitation amounts generally around 0.5-0.75" are expected, but localized amounts near 2" can`t be ruled out if additional thunderstorms ahead of the line are able to develop. The chances for this look highest over east-central Minnesota & northwest Wisconsin, & flood watches may be needed by tomorrow morning if a signal for heavier rain over these areas continues to develop. The line of storms will be through eastern Minnesota by early evening & out of our area into central Wisconsin by midnight, with clearing skies and cooler temperatures by sunrise. Strong northwest flow & cooler temperatures aloft develop behind the front, which will likely allow for another round of scattered diurnally- driven showers and thunderstorms across central Minnesota and western Wisconsin. Daytime temperatures will be quote cooler behind the front with highs in the mid-60s to low-70s. The upper air pattern remains fairly consistent through the weekend which will lead to generally cooler and drier conditions. A few diurnally-driven showers are possible daily with the cooler temperatures aloft, but the support for these wanes by later in the week. saturday could see a bit more widespread precipitation as models depict a weak shortwave embedded within the northwest flow passing over the Upper Midwest. daytime temperatures will generally be in the low to mid 70s into early next week. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1242 PM CDT Mon Jun 3 2024 Main aviation focus through early afternoon will be the potential for isolated to scattered showers & storms in far eastern Minnesota and western Wisconsin. Opted to keep the MSP TAF dry in collaboration with ZMP CWSU, as the latest hi-res data has pointed towards locations east of the terminal for the best chance of afternoon convection. Added in vicinity showers/thunder at RNH and EAU this afternoon, as confidence in scattered convection is growing, however confidence on impacts to each terminal remains on the lower side. Elsewhere, lingering MVFR cigs will clear and VFR conditions with light winds will prevail overnight. Next weather system will move in from the west starting late Tuesday morning, with widespread -TSRA expected just beyond the end of the 18z TAF period. KMSP...Keeping a close eye on the satellite/radar images this afternoon for a brief window of potential showers or storms. Any activity should move east of the terminal in short order, with quiet weather and light winds through the overnight. Winds increase out of the south Tuesday morning ahead a likely period of rain and thunderstorms Tuesday afternoon. A few storms may be strong to severe. /OUTLOOK FOR KMSP/ WED...VFR. Chc SHRA. Wind W 15-20G30 kts. THU...VFR. Wind NW 15-20G35 kts. FRI...VFR. Wind NW 10-15G25 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...ETA AVIATION...Strus