Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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525 FXUS63 KDLH 071152 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 652 AM CDT Sun Jul 7 2024 .KEY MESSAGES... - Scattered showers and a few thunderstorms expected today through tonight. - A few stronger storms may form in northwest Wisconsin this afternoon and early this evening. - Monday and Tuesday feature continued daytime storm chances before a downturn in activity is expected Wednesday and Thursday. - Gradual warming trend through the week. Above normal temps possible Friday and Saturday. && .DISCUSSION... Issued at 447 AM CDT Sun Jul 7 2024 A closed upper low embedded within a broader upper-level trough was centered over west-central Minnesota early this morning. As of 4 AM a broken arc of showers and thunderstorms stretched from southeast North Dakota into northwest Minnesota then curving toward the southeast across portions of central and east-central Minnesota into western Wisconsin and eastern Iowa. The upper low is forecast to propagate northeastward into the Arrowhead by this evening. Showers and storms will persist to the north and east of the low center along the axis of a thermal trough. Mostly clear skies were found over southwest Minnesota. Shower and storm coverage is expected to increase later this morning as the thermal trough rotates farther north into northern Minnesota to Upper Michigan. In the wake of this initial band of precip, expect partial clearing over the I-35 corridor and across northwest Wisconsin. High temperatures this afternoon will climb into the middle and upper 70s in those areas. The combination of several hours of heating and the morning precipitation will provide modest instability with MLCAPE of 1000-1500 J/kg by early afternoon. CAMs demonstrate a line of storms developing along a nascent cold front from Lake County down to near Spooner. The storms will push east- northeastward along and ahead of the boundary through this evening. Deep layer shear will increase to 30 to 35 knots ahead of the front which will raise the potential for a few strong to severe storms. Mid- level lapse rate of 6 to 6.5 degC/km are forecast, so there will be a small risk of hail up to 1 inch in diameter. Hodographs feature a little low-level curvature and LCLs will be around 3kft AGL. Given these parameters, the potential for a tornado will be low, but not zero over northwest Wisconsin. The upper trough pivot through the Upper Midwest Monday as the upper low drifts into northeast Ontario. Cool air aloft will support another round of showers and thunderstorms Monday afternoon and evening. A shortwave trough will propagate southeastward through the western periphery of the main trough for Tuesday, which will support another round of diurnal showers and storms. Ridging aloft will build for Wednesday and Thursday which will limit our shower and storm chances as the remnants of TS Beryl move northeastward through the Ohio Valley and into the central Great Lakes. With the building ridge, expect temperatures to trend gradually warmer through the week. A few spots will have a shot at 90 degrees Friday through next weekend. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 651 AM CDT Sun Jul 7 2024 Rain showers and a few thunderstorms will continue to spread northeast this morning with partial clearing late this morning into the afternoon. Periods of MVFR to IFR visibility and MVFR ceilings will accompany the showers and storms. HYR will have the best chance of storms this afternoon and early evening. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 447 AM CDT Sun Jul 7 2024 Winds will generally be in the 5 to 12 knot range over the next several days. A relaxed pressure gradient over the region should provide offshore flow during the overnights. Weak low pressure passing through the region today and tonight will turn winds northeasterly and then backing southwest for Monday. There is a slight chance of thunderstorms today and tonight, and again during the afternoon and evening hours of Monday and Tuesday. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .HYDROLOGY... Issued at 440 AM CDT Sat Jul 6 2024 A Flood Advisory continues across portions of the Rainy River Basin, extending as far east as Lac La Croix and as far west as the Rainy Lake outlet. Lingering high water from rains in June continue across the Rainy River Basin. Headwaters gauges on the Kawishiwi River, Basswood River, and Lake Vermilion have crested and are slowly but surely coming down (Lake Vermilion falling at a rate of a measly quarter inch a day). The Vermilion River is also beginning to fall once again, after taking a turn upwards from an additional round of heavy rains at the beginning of July. This has allowed the lake level increases on Crane Lake to slow considerably, nearly flatlining just above minor flood stage. Lac La Croix levels continue to increase though, the product of not only the high water from the Basswood River but numerous Canadian tributaries coming out of the Quetico as well. Latest data suggest that inflow and outflow are nearly meeting on Lac La Croix, which could help levels begin to crest soon. All this high water has led to some decent rises on downstream lakes, notably Namakan/Kabetogama (Nam/Kab) lakes (minor flooding ongoing), as well as levels beginning to increase on Rainy Lake (still within rule curves). Per the latest IJC water level bulletin, dam operators are working to maximize outflow through the basin. However, the sheer volume of water moving through the basin will still result in additional rises on these lakes. As water levels upstream crest and begin to come down, rates of rise on Nam/Kab should begin to slow and eventually crest. We`ve already seen the rates of rise begin to demonstrate signs of slowing. From July 1 to 3rd, Nam/Kab Lakes were rising at 2- 2.5" per day, but have recently slowed to 1-1.5"/day in the last 48 hours or so. General guidance suggest peak levels on Nam/Kab could be possible this coming week, but that is uncertain. As is usual for this basin, water will move slowly and recessions will happen at glacial speeds. Additional rainfall may cause brief rises in tributaries and extend the period of high water in core lakes. Boaters should expect high water, potentially hidden underwater hazards, and strong currents in constricted areas. Generally light winds are expected, except for possible brief erratic gusts out of thunderstorms, so wave heights should remain fairly minimal. The Flood Advisory is in effect through Wednesday, but may need to be extended based on observed conditions. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...None. && $$ DISCUSSION...Huyck AVIATION...Huyck MARINE...Huyck HYDROLOGY...Levens/Huyck