Area Forecast Discussion
Issued by NWS Duluth, MN

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000 FXUS63 KDLH 182352 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 652 PM CDT Sun Apr 18 2021 .DISCUSSION...(This evening through Saturday) Issued at 349 PM CDT Sun Apr 18 2021 A strong cold front will bring in much colder air for a few days along with some rain and snow into tonight. The Arrowhead has the best chance at seeing several inches of snow tonight with some light accumulation also expected in the snowbelt of the South Shore. A strong cold front stretched from the near Ely into central Minnesota into northern South Dakota this afternoon. Light rain was occurring along and behind the front but does transition to snow as observed at KINL. Forecast soundings show dry low layers and the combination of cold air advection and wet-bulb effects will cool boundary layer temperatures from west to east this afternoon into the evening. There remains some substantial differences among the models handling the low pressure system. The ECMWF and Canadian are slower and a bit further south with the low tonight which results in more QPF over far northeast Minnesota including the Arrowhead. The rest of the models are mixed but several of the higher resolution models do support some higher QPF but not as much as the Canadian/ECMWF. We did trend toward some higher QPF and based on forecast soundings, expect the rain to transition to snow through the evening. We issued a Winter Advisory for much of the Arrowhead this evening into the early morning hours for 2 to 5 inches of snow. The HREF supports these higher snowfall totals and is actually a bit more bullish. A period of gusty winds will occur both ahead of the front and after it`s passage as winds turn out of the northwest. 850MB temperatures will drop to -9C to -14C by 12Z Monday which will cause lake effect snow to develop along portions of the South Shore as well. We have snowfall along the South Shore tonight into Monday morning of 1 to around 3 inches, with the higher amounts most likely in northern Iron County. Overnight lows will drop below freezing and any slushy snow or water on untreated roads will freeze causing some slick spots. Highs Monday will only be in the mid thirties to lower forties and we increased cloud cover as cyclonic flow and the cold air support more clouds and perhaps some flurries or light showers. Lake effect snow chances will continue into Monday night along the South Shore with some additional light snowfall expected. We expect mainly dry conditions Tuesday into Thursday night with a warming trend toward Thursday. Highs on Thursday will rebound into the fifties and remain there into Friday. Another cold front and area of low pressure will move through the region Friday night into Saturday bringing a chance for light rain or perhaps some light snow. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 652 PM CDT Sun Apr 18 2021 A cold front is passing through the region at this hour, located in the vicinity of HYR. HYR will see a period of rain in the next hour or two with some MVFR visibilities possible at times. MVFR ceilings are expected at all terminals through the evening with scattered showers of rain or snow possible. There is a possibility that there may be some periods of VFR ceilings after midnight for some terminals. Winds will be gusty from the northwest at all terminals through the night. Gusts up to around 25 knots are expected. Wind speeds will lighten up slightly Monday afternoon. Diurnally-driven scattered snow showers may develop Monday morning and last into the afternoon before a bit of drier air moves in late-afternoon. Some MVFR visibilities may be possible for brief periods. && .MARINE... Issued at 349 PM CDT Sun Apr 18 2021 A strong cold front will move across Lake Superior this evening switching winds to north to northwest and causing them to increase. Winds will increase to 15 to 25 knots with gusts of 30 to 35 knots. The higher gusts are most likely from Little Marais to Grand Portage late tonight. Waves will build as a result of the increasing winds and be highest along portions of the South Shore. We continued the Small Craft Advisories that were issued this morning. In addition to the wind, an area of rain and snow will accompany the front. Much colder temperatures will occur tonight into Tuesday with some lake induced showers possible. The wind and waves will gradually decrease Monday. Northerly winds will continue Monday night but be around 15 knots or less for most areas. A weaker pressure gradient will lead to even lighter winds Tuesday. && .PRELIMINARY POINT TEMPS/POPS... DLH 27 39 24 39 / 60 10 0 10 INL 22 39 21 38 / 20 20 0 0 BRD 27 41 24 41 / 30 0 0 10 HYR 27 41 21 41 / 90 10 0 10 ASX 29 40 25 40 / 80 20 10 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...Winter Weather Advisory until 4 AM CDT Monday for MNZ012-021. LS...Small Craft Advisory until 1 PM CDT Monday for LSZ121-146>148- 150. Small Craft Advisory until 10 AM CDT Monday for LSZ143>145. Small Craft Advisory until 7 PM CDT Monday for LSZ140>142. && $$ DISCUSSION...Melde AVIATION...JDS MARINE...Melde

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