Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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700 FXUS63 KDLH 310545 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 1245 AM CDT Fri May 31 2024 .KEY MESSAGES... - The next round of rainfall and thunderstorms moves in from west to east this evening and lasts into Friday morning to bring a tenth to a half-inch of rainfall to the region. - Scattered showers and thunderstorms Saturday gives way to heavy rainfall and severe weather chances (15-30%), especially in the southern half of the Northland, Sunday afternoon and night. - A third round of moderate to heavy rainfall may occur next Tuesday into Tuesday night. && .DISCUSSION... Issued at 250 PM CDT Thu May 30 2024 Mid-level high pressure under a high-amplitude ridge exits the Northland this afternoon ahead of an incoming frontal boundary moving through the Upper Midwest and creating showers and thunderstorms in northwest Minnesota so far today. The deepest moisture plume overspreads north-central Minnesota around 00Z this evening and works east-southeastward through tonight. While there are a couple of hundred J of surface based CAPE yet this afternoon to work with in the Brainerd Lakes region, any later evening or overnight thunderstorms are most likely along and south of US Hwy 2 in northeast Minnesota and through the far northwest Wisconsin counties; severe weather is not expected tonight. There is a 60-80% chance of at least 1/4 of an inch of precipitation west of US Hwy 53 in northeast Minnesota tonight, with 40-50% chance for northwest Wisconsin. There is even a 60% chance for around or slightly above a 1/2 inch of rainfall tonight for the Brainerd Lakes into east-central Minnesota. This currently-progressive boundary is expected to stall out closer to the North Shore and southward along the MN/WI stateline Friday. Southwesterly flow with plenty of moisture advection along this low-level convergence zone supports continued rain shower and thunderstorm chances throughout the Friday daytime and Friday night time period in far eastern Minnesota and across northwest Wisconsin. A mid-level vort max lifts northward into the region Friday night to create a period of moderate rainfall under thunderstorms in northwest Wisconsin. The troughing that was responsible for the stalled boundary creating the showers and storms through Saturday morning finally exits the region Saturday daytime, but still with isolated storms and showers across the eastern half of the forecast area. Dry weather Saturday night into Sunday morning coincides with increasing moist southerly flow to create warm temperatures around 10 degrees above normal, around 80 F, in most inland locations. A deepening Canadian trough draws an even more moist airmass (deterministic guidance progged at 1.3-1.6 inches of precipitable water) into the region by the afternoon hours. There is a 15-30% chance of severe weather setting up in the Brainerd Lakes region and into east-central Minnesota by Sunday afternoon and into the evening hours as mid-level lapse rates around 8 C/km, 0-6km shear to 40 knots and 1500-2000 J/kg of CAPE support the SPC Outlook for severe weather in this southern half of the northeast Minnesota side of the forecast area. There is a 30-50% chance for at least 1" of rainfall in northeast Minnesota and 20-30% in far northwest Wisconsin and a 10-20% chance for around 2" of rainfall mainly in northeast Minnesota. The severe threat lessens by later Sunday night as shear breaks down and storm structure support aloft dissipates, although high rainfall rate showers could continue through Monday morning. At this point, ponding of water in intersections, high flows in drainage ditches, and elevated creek flows are looking somewhat likely Sunday evening and into Monday with saturated soils being shown across the region per satellite-derived imagery. Check with the National Water Prediction Services and the hydrologic ensemble forecast system hydrographs as well to keep up-to-date on the potential for mainstem river flow forecasts with these next few rounds of rainfall. Drier weather later Monday afternoon and night gives way to another low pressure system moving into the central US by Tuesday to create a potential (40-50% chance) third round of moderate to localized heavy rainfall in the region into next Wednesday. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1233 AM CDT Fri May 31 2024 A line of showers and isolated thunderstorms continue to make their way east. Occasional MVFR ceilings and visibilities are possible in the heaviest part of the line. After the line passes, conditions should return to VFR. However, patchy fog is developing across northwest Minnesota behind the showers, and opted to add a couple TEMPOS where fog could form. HYR will get two rounds of showers and storms as the front stalls over northwestern Wisconsin this afternoon and tonight. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 215 PM CDT Thu May 30 2024 Easterly winds gusting to 20 knots at the head of the lake this afternoon decrease in the later evening hours today as winds back southerly tonight. An incoming cold front creates the next round of thunderstorm chances over the lake late tonight into the pre-dawn hours early Friday morning. A stationary boundary sets up along the North Shore Friday daytime to keep widely scattered shower and storm chances for the head of the lake and mainly South Shore into Friday night. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...None. && $$ DISCUSSION...NLy AVIATION...KML MARINE...NLy