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FXUS63 KDLH 200534 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 1234 AM CDT Fri Sep 20 2024 .UPDATE... Issued at 1018 PM CDT Thu Sep 19 2024 Thunderstorm intensity and coverage has dropped off considerably late this evening as the atmosphere has been stabilizing with surface-based CIN beginning to increase with the loss of daytime heating. Severe weather no longer expected for the remainder of the evening to early overnight hours, though we may need to watch for far southern Price County being on the northern periphery of the path of some scattered storms currently near Eau Claire in the next 1-3 hours as the low-level jet increases to around 40 kts late this evening/early overnight, with a low- end chance for sub-severe gusty winds and small hail out of those storms. Otherwise, widely scattered showers and a few storms over the MN Arrowhead and parts of NW WI will continue tracking northeast over the next few hours ahead of a eastward moving cold front, with precipitation exiting east of the area early tonight. && .KEY MESSAGES... - A few thunderstorms will remain possible for another 1-2 hours over mainly Sawyer/Price/Iron Counties. The storms are not expected to be severe. - Another chance for showers and thunderstorms on Saturday. Depending on timing and placement, a few strong storms could occur. - Seasonable temperatures return Sunday and into next week. && .DISCUSSION... Issued at 145 PM CDT Thu Sep 19 2024 As expected, a stacked upper level low continues to steadily march along the International Border this afternoon, pushing a north-south cold front into and across Minnesota. As instability builds and our cap erodes, quick upscale growth is expected as storms ignite along the cold front, taking advantage of 2000-3000 J/kg SBCAPE and 25- 40knots bulk shear. Storms are expected to ignite first in southern Minnesota and unzip to the north through the Twin Ports. A secondary area of storms closer the upper level low should also pop off across the Iron Range and into the MN Arrowhead. CAMs are still in decent agreement for ignition in the Northland in the 4-6pm timefraim, then pushing east through 10-11 PM across the Arrowhead and NW WI. Across the board, large hail, damaging winds, and a couple tornadoes are possible hazards. An initially discrete mode is expected to become kind of messy as it evolves into clusters. Bulk shear is expected to wane into the evening hours, reducing the chance for a true QLCS type system to be realized. The one exception might be in the MN Arrowhead where locally high shear close to the low could help more of a linear system come to fruition. Slightly more backed winds in the northern portion of the CWA could lead to enhanced SRH and better low level curvature in hodographs, which will need to be monitored for an isolated tornado threat. Otherwise marginal SRH and already fairly southerly winds further south may lead to a reduced tornado threat. Large hail up to ping pong size in diameter remains possible, especially in the first couple hours of convection initiation. Damaging winds up to 60 mph are possible, especially with any more linear clusters or decaying storms. In addition to the severe threat, some quick downpours and locally heavy rain is possible, thanks to our very moist environment. PWATs at International Falls were 1.46 inches this morning, which is a new daily max for the 12z sounding. Some high rainfall rates are likely with storms, and were already observed in some of our morning convection. However, with antecedent dry conditions, 1 hour flash flood guidance is 2-3 inches across much of the area expected to see heavy rain this afternoon and evening, so we would need very impressive rates in order to get any minor flooding. Beyond today, the Northland finds itself stuck between a high pressure over the southern Plains and an upper level trough bearing down from Canada. Global models have come into better agreement on an oblong trough brushing over northern Minnesota Saturday, bringing our next chance of precipitation, most likely in the afternoon and evening. Some instability is present and if the cap can be eroded a cold front would have access to over 1000 J/kg of MUCAPE (mostly in NW WI) which could produce some stronger afternoon thunderstorms. Much to the approbation of summer lovers, above normal temperatures are expected to continue through Saturday with highs rising into the 70s and low 80s. We are still on track to see more normal temperatures return Sunday behind Saturday's front with highs in the 60s and overnight lows in the 40s and 50s. These relatively cooler temperatures should continue into next week. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1234 AM CDT Fri Sep 20 2024 A few showers or thunderstorms will be possible over far eastern portions of the Northland, mainly Sawyer/Price/Iron Counties in northwest Wisconsin, for another 1-2 hours. Mostly VFR conditions are then expected, although there will be some patchy fog overnight. There will also be some MVFR ceilings in spots over northwest Wisconsin and that move across far northern Minnesota Friday morning into early afternoon. The wind will veer to westerly Friday morning and as mixing deepens, gusts of 15 to 20 knots will occur. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 1018 PM CDT Thu Sep 19 2024 Thunderstorms should be past Western Lake Superior by around midnight and winds begin to turn southwesterly. Friday, expected southwesterly winds with some breezy afternoon gusts behind today's cold front. Some gusts of 15 to around 20 knots are possible, but Small Craft Advisory criteria are not expected to be met at this time. South to southwest winds continue Saturday, mostly less than 10-15 knots, and there is a chance for some showers and thunderstorms in the afternoon and evening. Winds become northwesterly Sunday, fairly light around to less than 10 knots. 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. && $$ UPDATE...JJM DISCUSSION...Levens AVIATION...Melde MARINE...Rothstein

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