Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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444 FXUS63 KDLH 210857 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 357 AM CDT Fri Jun 21 2024 .KEY MESSAGES... - Chances for showers and thunderstorms increase today, especially over northwest Wisconsin, with chances continuing into Saturday. Little rainfall is expected over far northern Minnesota today. - There will be a threat for heavy rain today into Saturday morning, although it has decreased and shifted south again. Portions of northwest Wisconsin have the highest chance at seeing 1-2"+. - The threat for severe storms has diminished Saturday but there remains a Marginal Risk (1/5) from east-central Minnesota into much of northwest Wisconsin. The window for severe is narrow and dependent on sufficient clearing to build instability. && .DISCUSSION... Issued at 358 AM CDT Fri Jun 21 2024 A stalled frontal boundary remained well south of the Northland this morning and the latest guidance has it moving slightly north into southern Minnesota into southern Wisconsin today. Showers and thunderstorms were moving along and north of this front early this morning from eastern South Dakota through southern Minnesota and northern Iowa. This activity will continue to move east-northeast and most of the heavy rain this morning will remain south of the Northland. However, high PWAT air will move north with values over the southern half rising to 1.5-1.8" today into tonight. 850-700MB FGEN will increase through the day and combine with a shortwave to provide lift for showers/storms further north into northern Minnesota. Instability will be meager at best today and tonight with the RAP forecasting a few hundred j/kg over the south half of the Northland. The threat for severe storms today/tonight is low and the SPC keeps the Marginal Risk just south of northwest Wisconsin. Confidence is not very high on POPS, especially tonight. CAM guidance suggests showers/storms will move north today especially over northwest Wisconsin and we have the highest POPS there. Most then bring a lull in coverage this evening before another shortwave moves in later tonight and the surface low lifts northeast. We didn`t buy in completely to the majority of the CAM guidance given the very moist airmass and FGEN but it trends hold, we may be able to reduce chances later this afternoon/tonight, especially over central into northern Minnesota. We do have more confidence that the heavy rain threat has shifted south but does remain over portions of northwest Wisconsin. HREF 24 hour QPF does show the potential for a narrow band of 1-2" from Washburn to Price Counties in northwest Wisconsin today into tonight and the WPC has a Slight Risk of excessive rainfall in that area. The ECMWF ensemble guidance paints a more bullish picture for heavy rain with probabilities of 60-90% for rainfall of 2" or greater from east-central Minnesota into northwest Wisconsin. However, we think the ECMWF is too far north with the surface low/warm front. The latest guidance does show it has shifted south compared to 24 hours ago and we think that trend will continue so feel it`s too high on its QPF. We have chances for showers/thunderstorms continuing Saturday, highest over northwest Wisconsin and in the morning. Instability is again meager, especially in the morning. Thunderstorm coverage will be low over central to northern Minnesota. CAM guidance suggests a lull in shower/storm coverage will develop Saturday morning overnight/early morning convection moves off. It`s possible we may too high with POPS Saturday morning. The threat for heavy rain is low on Saturday and the Northland has been removed from the latest excessive rain outlook. We remain in a Marginal Risk (1/5) for severe thunderstorms Saturday over east- central Minnesota into northwest Wisconsin and the main threat will be hail to 1" in diameter and damaging wind to 60 mph. The window for severe will be narrow and dependent on some clearing occurring to boost CAPE. Winds today into Saturday will be off Lake Superior and they will be stronger Saturday compared to today. There will be a HIGH risk for rip currents on Saturday. A shortwave in northwest flow aloft will bring more chances for showers/thunderstorms Sunday. Widespread heavy rainfall and severe storms are not expected. There will be periodic chances for more showers/storms next week but the upper flow will be more progressive diminishing the heavy rain threat. The best bet for a dry day will occur Wednesday with high pressure over the region. Temperatures will trend warmer Sunday-Tuesday then cool slightly. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1242 AM CDT Fri Jun 21 2024 VFR conditions initially will drop to MVFR then IFR across southern portions of the Northland including KDLH/KBRD/KHYR with VFR conditions prevailing through the period at KINL. Showers and thunderstorms will develop either late tonight or Friday morning from south to north but they are not expected to make it into far northern Minnesota including KINL. The rain may be heavy at times. Instability is limited and so should be thunderstorms for most and we only went with showers and added a VCTS to some of the TAFS. Fog will also develop where the rain is most widespread and around Lake Superior with IFR visibility at times. The general trend will be for showers/storms to develop late tonight/Friday morning continue through a good portion of the day decreasing from west to east in the afternoon/evening. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 358 AM CDT Fri Jun 21 2024 Easterly winds will occur today into Saturday. They will be from 5 to 15 knots today with a few higher gusts. They will increase to 10 to 20 knots Saturday with some gusts to 25 knots. Conditions will become hazardous for smaller vessels Saturday and Small Craft Advisories may be needed for portions of the nearshore waters. Winds will shift to west or northwest Saturday night and to west or southwest Sunday. Speeds should be at or less than 15 knots. There is a risk of thunderstorms this afternoon into Sunday. Severe storms are not expected. 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...Melde AVIATION...Melde MARINE...Melde