Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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481 FXUS63 KDLH 192141 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 441 PM CDT Wed Jun 19 2024 .KEY MESSAGES... - Chances for showers and thunderstorms return to the area Thursday into Thursday night. - Several rounds of rain and storms are forecast Friday through the weekend. A few strong storms are possible and there is a risk of additional heavy rain. - The greatest risk of additional heavy rain is generally south of a Walker to Duluth to Bayfield, WI to Wakefield, MI line including all of NW WI Friday night through Saturday. && .DISCUSSION... Issued at 440 PM CDT Wed Jun 19 2024 High pressure over the region this afternoon will provide a respite from the active weather of the past week or so before drifting northeastward into Ontario Thursday and Thursday night. Persistent southwest flow aloft will include a surge of moisture and a ripple in the height fields late tonight and Thursday. Diffluence aloft and ascent supported by 700-600 mb frontogenesis should generate an area of showers from western Minnesota into central Minnesota by 7 AM Thursday. Dry air aloft below the cloud-bearing layer will translate into widespread radar echoes, though a smaller footprint of rain reaching the ground. Have included a chance of sprinkles overnight after 06Z. Rain chances increase through the day Thursday, except over far northern portions of Minnesota, generally north of the Iron Range. Isentropic ascent will be aided Thursday night into early Friday by a passing shortwave trough and 850 mb convergence on the nose of a weak low-level jet. As the high pressure departs, a warm front will lift northward across the Midwest to near the Iowa/Minnesota border by 12Z Friday and to eastern South Dakota across central Minnesota and northern Wisconsin by 12Z Saturday. Isentropic ascent north of the front will continue to support shower chances and a few thunderstorms Friday and Saturday. The position of the warm front will serve as the northern edge for any severe weather threat Friday and Saturday, keeping the greatest potential for strong to severe weather south of our forecast area. A few strong to severe storms are not out of the question, particularly near and a little north of the boundary late Friday night and Saturday. The greatest potential for excessive rainfall will be Friday night through Saturday, with the highest risk generally south of a Hinckley, MN to Mercer, WI line. WPC added a "Moderate" risk of excessive rain to much of the southern half of Minnesota and a sliver of west-central and northwest Wisconsin this afternoopn. Considering the placement of rainfall from the past week, this seems appropriate. The areas most likely to see heavy rain Friday night through Saturday already received considerable rainfall over the past week. A shortwave trough will propagate eastward out of the Rockies Friday night and across the Plains on Saturday, which will kick the baroclinic zone over the Upper Midwest eastward Saturday night and Sunday. The risk of heavy rainfall will decrease thereafter with a more progressive pattern forecast. There will be additional rain and storm chances next week, roughly every other day. The risk of additional flooding will decrease despite the rain chances since the flow will be more progressive than the stagnant baroclinic zones over the past week. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1240 PM CDT Wed Jun 19 2024 VFR ceilings are expected for the rest of the afternoon into this evening with northwest winds. There is a small risk of fog developing at INL, HIB, BRD, and HYR tonight. The mitigating factor for any fog chances will be the arrival of high clouds. As high pressure departs to the northeast overnight and Thursday, look for high clouds to return. Rain chances increase after 20.18Z. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 440 PM CDT Wed Jun 19 2024 A few wind gusts to 25 knots remain possible along the immediate shoreline of the North Shore this evening. High pressure over the region will gradually lift northeastward tonight and Thursday. Winds will turn northeasterly by Thursday afternoon and wind speeds will increase. Look for sustained winds of 5 to 15 knots with gusts of 10 to 20 knots. The strongest winds will be near the Twin Ports. Winds weaken Thursday night. A diurnal strengthening of the northeast winds will continue Friday and Saturday. Winds will back northwesterly by Sunday. Small Craft Advisories may eventually be needed near the Twin Ports should wind and waves increase above current forecasts. Shower and storm chances return Thursday and persist through the weekend. Some storms may be strong to severe. Heavy rainfall is likely, particularly Friday night and Saturday, which may reduce visibility to less than 1/4 mile at times. 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...Huyck AVIATION...Huyck MARINE...Huyck