Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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355 FXUS63 KMQT 011355 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 955 AM EDT Sat Jun 1 2024 .KEY MESSAGES... - Showers gradually move eastward across western Upper MI this morning into central Upper MI late this afternoon and evening. - Frequent opportunities for showers and thunderstorms over the next 7 days, with a break expected on Sunday and Tuesday. - Above normal temperatures through the first half of next week, then turning cooler. && .UPDATE... Issued at 955 AM EDT Sat Jun 1 2024 Hit and miss showers continue mainly across the western UP so far this morning, in proximity to a diffuse frontal boundary over western Lake Superior and the western UP. However, another wave moving through northern WI into the UP for the late morning and early afternoon will allow some more shower activity to spread into the central UP. PoPs have been adjusted to reflect greater extent of showers through the early afternoon. A few rumbles of thunder are not out of the question. Otherwise, the forecast remains on track. && .SHORT TERM /THROUGH TONIGHT/... Issued at 311 AM EDT Sat Jun 1 2024 Water vapor imagery and RAP analysis show a deep mid-level low w and sw of Hudson Bay, centered along the northern border of Saskatchewan and Manitoba. Prominent shortwave associated with this mid-level low has lifted to Hudson Bay. Its associated cold front has essentially stalled over western Lake Superior as the shortwave has tracked well to the n now. A small, but well-defined wave is noted tracking along the border of ND/Saskatchewan/Manitoba. This wave is also working to hold up progression of the front. Upper diffluence from the right entrance of 100kt upper jet extending from far northern MN toward southern Hudson Bay is aiding a band of shra extending from western Lake Superior thru southern MN. This band of shra as been lifting more n than e during the night, and at present, the shra are now just to the w of Upper MI. Otherwise, it`s a quiet night across the fcst area with light winds and abundant high cloudiness. Temps range thru the 50s to lwr 60s F. With the upper diffluence aiding the band of shra to the w shifting e this morning, expect the shra to also shift e back into western Upper MI. To the s, a shortwave is currently over the Mid- Mississippi Valley. Shra associated with this feature may try to develop northward into southern Upper MI late morning/early aftn. Most guidance suggests that won`t happen, and fcst reflects that idea. This aftn, the shortwave currently tracking e vcnty of far northern ND will lift into northern Ontario. This wave will give an eastward kick to what`s left of the cold front currently over western Lake Superior. Front at the sfc essentially dissipates, but up at 850mb, a trof and rather sharp theta-e boundary is noted. This trof/boundary shifts e during the later aftn/evening and should support invigoration of shra over western Upper MI. With up to a few hundred j/kg of MLCAPE avbl this aftn, isold tsra will be possible as well. This band of shra/isold tsra will shift into central Upper MI late aftn/early evening then continue e thru the evening while diminishing. Most, if not all, of the shra may dissipate before reaching Luce/Schoolcraft counties. Clearing skies, little wind, and the rainfall from today may lead to patchy fog development overnight tonight. Expect high temps today mostly in the upper 60s to mid 70s F. Temps tonight will fall back to the upper 40s and lwr 50s F. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 259 AM EDT Sat Jun 1 2024 Expect dry conditions to return to the U.P. Sunday as the cold front leaves the far east during the early morning hours and weak sfc ridging returns to the area. With sfc ridging and zonal flow in the mid-levels over the area during the day Sunday, expect a diurnal cu field to develop over Upper MI by the afternoon hours as troughing and warm air advection begins to make its way back over the area by early Sunday evening. With PWATs around 0.75 inches, there is an outside chance (around 10%) that we could see a stray lake breeze induced rain shower or two over the central and east late in the day. However, given the high pressure ridging at the sfc, the dry air in the PBL should eat away any moisture that falls out of the cu field. Should anything make it to the sfc, expect short-lived sprinkles to light rainfall. Moving into Sunday night, expect the mostly clear skies to progressively give way to clouds as a cold front bringing showers and storms approaches from northern MN. The most recent NBM run has pushed back the timing of the showers and storms arriving over the western U.P. late Sunday night and Monday morning. In addition, the model consensus shows little, if any CAPE to work with and 0-6 km bulk shear values generally less than 30 kts. Therefore, severe weather is not expected at this time over the western U.P. Monday and Monday evening. The cold front will slowly crawl from west to east early this week across our area before weak high pressure ridging returns to the U.P. Tuesday. As this occurs, expect rain showers and thunderstorms across our area from Monday into early Tuesday morning. The low behind the cold front early this upcoming week will lift towards Hudson Bay with time before being phased with an amplifying Clipper low by the middle of next week. Strong warm air advection from the Gulf is brought over our region ahead of the cold front of the low`s arrival Tuesday and Tuesday night. Therefore, expect high temperatures Tuesday to break into the 80s across the interior areas. I could see dewpoints and RHs being lower than what`s currently being predicted by the NBM for Tuesday; if there is less cloud coverage than what`s currently predicted (partly cloudy skies at the moment), then mixing in the boundary layer will be greater, and thus dewpoints and RHs will be lower (I would wager their is around a 50% chance of this occurring at this time). As it stands now though, RHs are not expected to dip below 50%. The cold front of this low begins moving into the area late Tuesday afternoon/early Tuesday evening over the far west, with showers and thunderstorms moving over the rest of the U.P. Tuesday night through Wednesday. Once the cold front passes through, the vertically- stacked low sits over northern Ontario and brings cold air advection across our area. As this occurs, expect additional weak shortwaves rotating around the parent low to move across the Upper Great Lakes, bringing additional rain showers and possibly (15% chance) a thunderstorm or two back across the area to finish out the work week. Thus, along with the scattered rain chances, expect to see below normal high temperatures late next week; this is reflected well in yesterday`s 12z run of the EFI for the daytime Friday, with some of the ensemble runs showing highs in the 10th percentile or cooler of climatology. Therefore, we could see some unseasonably cool daytime temperatures come late next week. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 741 AM EDT Sat Jun 1 2024 Weakening cold front and a couple of disturbances will bring sct shra to the area into this evening. Isold tsra are possible this aftn as well. At IWD, VFR should prevail thru the fcst period. Passing -shra are expected thru the morning, possibly dropping vis to MVFR and leading to ocnl MVFR cigs. During the early to mid aftn, a few tsra may develop across western Upper MI. Potential of IWD being directly affected is low, so only VCTS was included for a couple of hrs. At CMX, VFR is likely to prevail thru this evening. Passing -shra are expected thru mid aftn with low potential for brief MVFR. Late tonight, fog potential increases. For now, fcst includes MVFR. At SAW, VFR will likely prevail thru this evening. Some -shra are possible during the aftn and early evening. Late tonight, fog potential increases, and fcst reflects vis falling to IFR. && .MARINE... Issued at 259 AM EDT Sat Jun 1 2024 Light winds of 20 knots or less continue across Lake Superior until a cold front crawling eastwards across the lake brings southeasterly winds of 20 to 25 knots over the higher elevation platforms and the Lake Superior southerly nearshores Monday. Behind this, expect a return to light winds Tuesday, before stronger winds could possibly return with the coming of a second cold front Tuesday night into Wednesday; expect gusts to around 20 knots from the southwest over the western half. Moving into the latter half of next week, we could see higher winds from the northwest as cold air advection from Canada works in tandem with weak shortwaves dropping down across the area to mix stronger winds aloft to the lake`s sfc. Thunderstorms are possible across the south central and eastern portions of Lake Superior this afternoon and evening as a weak cold front moves through. Thunderstorm chances return from Sunday night to early Tuesday morning as a second cold front slowly makes its way from west to east across the lake. Additional thunder chances return late Tuesday and continue through Wednesday as yet another cold front pushes through from west to east across the lake. No severe weather is expected from these storms. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Dense Fog Advisory until 11 PM EDT /10 PM CDT/ this evening for LSZ162-263-264. Lake Michigan... None. && $$ UPDATE... SHORT TERM...Rolfson LONG TERM...TAP AVIATION...Rolfson MARINE...TAP