258 FXUS63 KDLH 051146 AAA AFDDLH Area Forecast Discussion...UPDATED National Weather Service Duluth MN 546 AM CST Tue Nov 5 2019 .UPDATE... Issued at 546 AM CST Tue Nov 5 2019 Update for new 12Z Aviation Discussion below. && .SHORT TERM...(Today through Wednesday) Issued at 317 AM CST Tue Nov 5 2019 A closed upper low in northwest Ontario, and its associated long wave trof, were affecting the forecast area early this morning. At the surface, cold high pressure was working its way through the Dakotas. Embedded impulses were also working across the region and generating some clouds and a few snow showers/flurries. The closed low/trof will depart by noon, with the last of its impulses moving through the area. Some additional snow showers may occur in response. Otherwise, drier air from the Dakotas high will move across the region today. Aforementioned high will drift over the area by late afternoon, ending all snow. Neutral temp advection today, but still way below normal max temps. In fact, forecasted max temps today, are the normal minimum values. Upper flow turns more west northwesterly tonight, with neutral temp advection over the northern area, weak warm air advection over the southern zones. Minor model differences in resolving the amount of moisture reaching the southern portion of the area with respect to the warm air advection. The ECMWF has more moisture and also some pops/QPF across this area, and has some support from the GEFS ensemble mean. Other deterministic models are drier. Used a blend to resolve these differences for pops tonight. Have some pops along the northern zones as well, in response to upper level energy moving quickly along the Borderland tonight. Additional impulses are progged to move along the Borderland on Wednesday, while high pressure is re-enforced over the Dakotas. A mainly dry atmosphere is in place. However, there will be just enough moisture to generate some snow showers in the morning. A northwest wind over Lake Superior in the afternoon will lead to some lake effect snow showers in the higher terrain of north central Wisconsin. Dry air in this area, and neutral temp advection in the 1000-900mb layer, will limit the snow amount potential, but have some pops regardless. Much below normal max temps again. .LONG TERM...(Wednesday night through Monday) Issued at 317 AM CST Tue Nov 5 2019 Below to well below normal temperatures are expected throughout the long term with a few chances of widespread light snow. Lake effect snow is also likely for the snowbelt areas of northwest Wisconsin. Wednesday evening will find a broad upper-level trough over the International Border area from Montana east into New England. Cold 850 mb temperatures will be centered over northern Manitoba and northwesterly flow aloft will result in cold air advection into the Northland. Surface high pressure be centered over eastern Montana and western North Dakota. The broad trough sharpens as a jet streak dives into the Northern Plains. By Thursday evening the trough axis will be centered over the eastern Great Lakes with northwesterly flow over the Northland. The surface high pressure will move into the Upper Mississippi River Valley. The persistent northwest flow and cold air advection will result in lake effect snow showers over snowbelt areas of northwest Wisconsin. With inland lakes still relatively warm, there is a potential for light snow or flurries downwind of Lake of the Woods, Rainy Lake, Lake Vermilion, Leech Lake, and Lake Winnibigoshish. One mitigating factor to the inland lake effect snow will be the dry air in the boundary layer. Low-level flow may need to line up over several lakes to provide sufficient sensible heat and moisture flux to support snow. With a much larger fetch over Lake Superior, lake effect snow is more likely over portions of northwest Wisconsin. The surface high pressure will slide farther eastward on Friday with low-level winds turning south to southwesterly. Warm air advection is expected and temperatures will trend warmer, but still below normal. The potential for additional snow showers Friday is low. Look for highs in the middle 20s to low 30s. Saturday is shaping up a little warmer with highs in the upper 20s to middle 30s. A potent jet streak will move through the northwest flow aloft and will support the development of an area of low pressure over northern Manitoba by Friday evening. This low will move quickly into northern Ontario by Saturday morning pulling a strong cold front through the region. Light snow is likely behind the front as the cold air advection and falling heights wring out the earlier moisture. High temperatures on Saturday may be recorded in the morning with falling temps during the late morning and afternoon hours. Lake effect snow showers are expected Sunday and Monday as northwest winds and cold air advection return. Highs on Sunday will reach the middle teens and low 20s. Similar conditions are expected Monday. && .AVIATION...(For the 12Z TAFS through 12Z Wednesday morning) Issued at 546 AM CST Tue Nov 5 2019 Northwest winds aloft will keep MVFR ceilings in play at HIB with VFR conditions elsewhere. Lake effect snow showers from numerous relatively warm inland lakes are expected at sites where the cloud cover remains in place. VFR visibilities are expected, even in snow showers. Visibility will likely be lower, MVFR/IFR, on approach to HIB due to heavier bands of snow downwind of various industrial stacks to the west and northwest of the field. && .MARINE... Issued at 317 AM CST Tue Nov 5 2019 Warm lake temperatures and cold air aloft will allow strong westerly winds aloft to mix down to to the surface. Wind and waves will remain hazardous to smaller vessels through this morning. Wind speeds and resultant waves will decrease by late morning and early afternoon as the pressure gradient at the surface and aloft relaxes. Northwest winds will continue tonight through and Wednesday in the 10 to 20 knot range before decreasing to 10 to 15 knots Thursday. && .PRELIMINARY POINT TEMPS/POPS... DLH 25 16 26 12 / 0 10 10 0 INL 23 14 24 12 / 0 10 20 20 BRD 28 20 27 13 / 0 10 10 0 HYR 27 17 28 12 / 0 10 10 0 ASX 28 17 29 15 / 0 10 30 20 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...Small Craft Advisory until noon CST today for LSZ121-140>148. && $$ UPDATE...Huyck SHORT TERM...GSF LONG TERM...Huyck AVIATION...Huyck MARINE...Huyck