Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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805 FXUS63 KDLH 040916 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 416 AM CDT Thu Jul 4 2024 .KEY MESSAGES... - Active pattern continues with a chance for moderate rain this afternoon through Friday. The greatest chance of 0.5-1.5 inches is mainly south of a line from the Brainerd Lakes to Moose Lake to Ashland, WI. - Another system will bring additional chances of rain this weekend. - High water persists across the Rainy River Basin and a Flood Advisory is in effect. See Hydro discussion for more details. && .DISCUSSION... Issued at 416 AM CDT Thu Jul 4 2024 A nearly stationary front stretched from central Nebraska to southwest Minnesota to near Green Bay, WI to eastern Upper Michigan early this morning. A weak area of low pressure was positioned near Sioux City, IA. A modest baroclinic leaf signature was noted on GOES-East IR imagery from western Iowa into northeast Minnesota. A 90-100 kt jet streak was located upstream over Idaho and Wyoming. Cyclogenesis is forecast to continue as the jet streak rounds the base of an upper-level trough and propagates into the Midwest. Look for the surface low to strengthen through today as it move eastward along the front. Increased ascent will lead to widespread showers and a few thunderstorms over southern Minnesota initially spreading northward into central Minnesota and northwest Wisconsin this afternoon. Modest instability is forecast with tall, skinny MLCAPE of 750-1250 J/kg forecast. Deep layer shear will be low, around 20 to 25 knots. This pattern will support mainly pulse storms which may be capable of small hail to around half an inch in diameter. Relatively deep warm cloud depths and ample moisture through the column suggest a potential for locally heavy rainfall where storms develop. In our area, the greatest threat of locally heavy rain will be from the Brainerd Lakes east into northwest Wisconsin and mainly this evening. Weak inflow layer winds of 10 knots or less will limit moisture transport. The surface front will remain south of our area, so the greatest risk of heavy rain will likely develop farther south across central and southern Minnesota into central and southern Wisconsin. The WPC Excessive Rainfall Outlook highlights that area clearly. Areas along the International Border have the lowest chance of precipitation over the next 48 hours. Temperatures today will top out in the middle to upper 70s. The surface low is forecast to slowly advance east- northeastward on Friday keeping rain chances over northwest Wisconsin and the I-35 corridor to wrap up the week. Partial clearing and weak cold air advection over Minnesota will support a chance of showers and storms developing during the afternoon over north-central and central Minnesota, including International Falls, Grand Rapids, and Brainerd. Small hail will be possible once again with any storms that develop along with a chance of locally heavy rainfall. The slow-moving system is forecast to pull away from the Northland Friday night and Saturday. Lingering cold air advection aloft will support a few isolated showers or storms Saturday afternoon and evening. A shortwave trough will move into the region from the northwest Saturday night and Sunday which will support additional shower and storm chances through the weekend. Cool air aloft will persist into early next week keeping a diurnal threat of showers and storms in the forecast until late next week. Temperatures will generally remain near normal. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 101 AM CDT Thu Jul 4 2024 Patchy fog overnight expected to create MVFR/IFR visibility at INL, HIB, and HYR. Showers and a few thunderstorms will build northeastward this afternoon and evening. MVFR visibility expected at BRD with the showers. Less confidence in reduced visibility at HYR so kept VFR for now. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 416 AM CDT Thu Jul 4 2024 Light westerly winds this morning will back northeasterly by this afternoon and gradually strengthen in response to developing low pressure over southwest Minnesota. Conditions may become hazardous for small craft in the southwest arm of Lake Superior, particularly near the Twin Ports. Look for winds to strengthen to around 10 to 15 knots with gusts as high as 20 knots. Waves will build to 1 to 3 feet. If winds and waves trend higher than currently forecast, a Small Craft Advisory may become necessary. Winds and waves will gradually weaken on Friday as the low pressure pulls away from the Northland. Expect relatively light winds of 5 to 10 knots with gusts as high as 15 knots through the weekend. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .HYDROLOGY... Issued at 416 AM CDT Thu Jul 4 2024 A Flood Advisory remains in effect 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 to be present across the Rainy River Basin. Far headwaters gauges on the Kawishiwi River, Basswood River, and Lake Vermilion have crested and indicate that the flood wave or peak water levels are slowly making their way through the basin. However, rises continue on the Vermilion River and Lac La Croix and downstream of those points. This has led to high water and some minor flooding on Crane Lake and Namakan/Kabetogama (Nam/Kab) lakes, as well as lake levels increasing on Rainy Lake. Per the latest IJC water level bulletin, dam operators have pulled all logs at Kettle and Squirrel Falls, and continue pulling logs at International Falls as conditions allow in order to maximize outflow through the basin. However, the sheer volume of water moving through the basin will still result in rises on these lakes due to the natural constriction of the flow. Vermilion River is forecast to crest late this week and then begin slow recessions. Water level rises further downstream on Nam/Kab are likely to continue (latest rates of rise have been an inch or two a day, this is likely peak rates of rise and should begin to slow by the weekend), with peak water level early to mid next week. 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. Some northerly winds are possible Friday, but are not expected to be strong, so wave heights should be minimal. The Flood Advisory currently extends through next 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...Huyck/Levens