Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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988 FXUS63 KDLH 220755 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 255 AM CDT Sun Sep 22 2024 .KEY MESSAGES... - Frost expected tonight through sunrise Monday morning for many locations across the Northland inland from Lake Superior. - Cooler weather today through Tuesday, then widespread high temperatures in the 70s return for mid-week into next weekend - Very little to no rain (less than 15% chances) through the upcoming week. && .DISCUSSION... Issued at 256 AM CDT Sun Sep 22 2024 Current Conditions - Today: A cold front that moved through the Northland on Saturday has now shifted east of the area, with winds having shifted to the northwest under clearing skies, though some stratus clouds will linger in NW WI for a few more hours. Some gustier katabatic winds continue through early morning along the North Shore, with gusts up to 25-35 mph as cooler air funnels down the terrain and river valleys of the North Shore. These winds should gradually subside on Sunday morning. Broad high pressure slides into the Upper Midwest today, leading to mainly sunny skies across the majority of the Northland, as well as a cooler and drier airmass. High temperatures will be around normal, topping out in the low to upper 60s. Some daytime wind gusts up to 15 to 20 mph are expected, but will drop off and become light this evening and calm tonight as the center of the high pressure moves directly overhead. Frost Tonight through Sunrise Monday: Calm winds, dry air, and clear skies will lead to a favorable setup for efficient radiational cooling tonight, which should allow low temperatures to plummet into the mid to upper 30s across most of the Northland locations inland from Lake Superior tonight into early Monday morning. Some of the typical colder spots in the Iron Range and interior Arrowhead could touch the low 30s and see low temperatures around freezing, as well. Given this temperature forecast, a Frost Advisory has been issued for 2 AM - 8 AM on Monday morning. Also can`t rule out some very patchy frost in the Iron Range, inland Cook County, and parts of NW WI on Monday night, but the low temperature signal isn`t quite as cold as it is for tonight into early Monday morning. Quiet Workweek Forecast: The weather pattern for the rest of the week remains relatively benign, with a predominately dry forecast (precipitation chances less than 15%) until next weekend at the earliest. An upper-level shortwave trough over the coast of British Columbia this morning will travel east across the Canadian Prairies later today and Monday before diving southeast across the Dakotas/Minnesota late Monday and Tuesday. This system will not have access to Gulf of Mexico moisture and the moisture it will have (PWATs of 0.7-0.8", near the average value for late September) does not look sufficient to produce any rainfall in the Northland Monday night into Tuesday due to a layer of dry air from the surface up to 750mb. This system will keep high temperatures on Monday and Tuesday mild in the mid-60s to low-70s, however. Global ensembles are in good agreement in a broader upper-level ridge moving over the central CONUS for the mid-week into next weekend timeframe, albeit with some slight variations in amplitude and location of the ridge`s axis. Regardless, this pattern will push widespread high temperatures back into the mid-upper 70s for the Northland for Wednesday into next weekend, though overall humidity levels will remain lower than what we saw this last week. There is a lower confidence scenario for next weekend where a weak shortwave trough or two rounds the northern portion of the upper-level ridge, in which case the Northland could be grazed by light rain, but precipitation chances are still only 15-20% at this point as most global ensemble members keep next weekend dry. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1230 AM CDT Sun Sep 22 2024 VFR conditions persist throughout the this TAF period. Some VFR stratus around 5000 ft in northwest Wisconsin behind a departing cold front will exit east through around 08-10Z. After that, there will be a few high clouds streaming over HYR today, and FEW/SCT diurnal cumulus affecting INL and other areas near the International Border during the daytime hours today. Winds will remain northwest to north-northwesterly through much of the TAF period at around 5-10 knots overnight, then at 8-12 kt with gusts to 15-20kt from mid morning through late afternoon before turning light and variable this evening into tonight. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 256 AM CDT Sun Sep 22 2024 Northwesterly winds around 20 knots and waves of 2 to 4 feet continue through early this morning in the Apostle Islands. Additionally, wind gusts up to 25 to 30 knots persist along the nearshore waters of the North Shore north of Silver Bay due to some katabatic winds as cooler air funnels down the higher terrain and river valleys of the North Shore. Grand Marais has been consistently gusting to around 30 knots since 11 PM because of this. A Small Craft Advisory is in effect for the aforementioned locations until 9 AM CDT this morning. Winds remain northwesterly but calm to 5 to 15 knots, with occasional gusts to 15-20 knots today before becoming light out of the north this evening and tonight. No significant weather or winds expected through mid week. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...Frost Advisory from 2 AM to 8 AM CDT Monday for MNZ010>012- 018>021-026-035>038. WI...Frost Advisory from 2 AM to 8 AM CDT Monday for WIZ001>004- 006>009. MARINE...Small Craft Advisory until 9 AM CDT this morning for LSZ140>142-147-150. && $$ DISCUSSION...Rothstein AVIATION...Rothstein MARINE...Rothstein