Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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894 FXUS63 KMQT 021149 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 749 AM EDT Sun Jun 2 2024 .KEY MESSAGES... - Patchy fog expands until sunrise and will become locally dense. Fog will burn off within a couple of hours after sunrise. Marine fog on portions of Lake Superior may be an issue through the day. - Isolated afternoon showers possible interior eastern Upper MI due to converging lake breezes. - Frequent opportunities for showers and thunderstorms over the next 7 days. - Above normal temperatures through the first half of the week, then turning cooler for the last half and next weekend. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 323 AM EDT Sun Jun 2 2024 Water vapor imagery and RAP analysis show a deep mid-level low centered over northern Manitoba. To the s of this feature, flow is zonally oriented along the U.S./Canada border from the Pacific NW to Lake Superior. Upstream, the next shortwaves of interest are over the northern Rockies. Shortwave that was over far northern ND 24hrs ago has lifted ne and is nearing James Bay. This wave has helped to drive a drier air mass aloft into Upper MI. At the sfc, a weak high pres ridge is over the Upper Mississippi Valley. Weak pres gradient over the fcst area is leading to light/calm wind at many locations early this morning. Where skies are clearing and where rainfall occurred yesterday and last evening, the light wind is allowing radiation fog to develop. So far, coverage is limited. Current temps range thru the 50s F. Expect fog to expand thru sunrise as areas of lingering cloudiness clear out. The fog will likely become locally dense. As we are just under 3 weeks from the summer solstice, fog should quickly burn off within a couple of hrs of sunrise as insolation rapidly increases, leaving behind sunny skies. Aforementioned sfc high pres ridge will shift to the western Great Lakes today, allowing lake breeze circulations to rule the day. Over the eastern fcst area, the converging lake breezes from Lake MI and Lake Superior raise the prospect for a few -shra to develop. Models suggest at least a few hundred j/kg of MLCAPE developing, but as is often the case, the NAM is greatest. The NAMnest has upwards of 1000j/kg of MLCAPE and will be discounted. Based on fcst soundings, it appears there will be cap to sfc based convection somewhere in the 10-15kft range, so cloud depth should be sufficient for isold -shra development, but not thunder unless the outlier higher MLCAPE solution occurs. Fcst for the aftn will reflect schc pops, around 20pct, centered across southern Luce County where signal from models is most consistent, but isold -shra could occur as far w as northern Delta/adjacent Alger counties. To the w, building mixed layer will tap drier air, driving dwpts down to the upper 30s/lwr 40s F interior w half. With aftn temps in the 75-80F range, RH will tumble toward 25pct. Winds will be very light in that area today, not much more than around 5mph, limiting fire wx concerns. && .LONG TERM /TONIGHT THROUGH SATURDAY/... Issued at 323 AM EDT Sun Jun 2 2024 Mostly clear skies this evening give way to rain showers and a few thunderstorms over the far western U.P. by Monday morning as a cold front begins pushing into the area. With clouds moving in tonight over the west half in particular, expect lows over the west half to be in the 50s to near 60 over the far west. Meanwhile, with less cloud cover overhead, expect lows to get down to around 50 in the east. No severe weather is expected Monday as the cloud coverage will limit CAPE and lapse rates; in addition, bulk shear values look to generally be less than 30 knots. That being said, it is still possible that we could see a stronger cell or two that could produce gusty winds and small hail. With the NAEFS and European ensembles showing PWATs above 1.25 inches (which is above the 90th percentile of modeled climatology), we could see some heavy rainfall at times over the western half of the U.P. Monday. While the heavy rainfall looks to be very sporadic in nature, there is a chance (30-50%) that we could see some isolated spots get above 1 inch of liquid before the sun sets; hopefully, this will alleviate the remaining moderate drought concerns over in the western U.P.. As the front slowly makes its way into the central and eventually eastern portions of Upper Michigan late Monday afternoon into Monday evening, CAMs show convective activity dwindling as frontogenesis weakens. Therefore, lighter rainfall amounts are expected across the eastern half of the U.P. late Monday. While it looks like some weak high pressure ridging moves over the area Monday night into Tuesday, model guidance has trended up rain chances slightly over the past 24 hours. Therefore, the predicted cloud cover has increased a little since yesterday morning, with partly to mostly cloudy skies now expected across the area as a weak shortwave is expected to precede a second cold front approaching from the Northern Plains. The shortwave could bring some light rain showers and a couple of thunderstorms across the area early Tuesday, particularly over the south central and east where the chances are highest (15-25%). Warm air advection moving over the area Tuesday will allow for high temperatures to get well above normal, with spots in the interior west and possibly east getting above 80 degrees. Given the moisture from the Gulf and somewhat cloudy skies overhead, we could see dewpoints get into the mid to upper 60s in a few places, mainly over the interior west (a.k.a. it may feel a bit muggy). With the cold front looking to arrive during mainly the overnight hours, severe thunderstorms aren`t expected. However, with the exact timing of the front`s arrival not pinned down quite yet, some model guidance showing MUCAPE over 1000+ J/kg during the early evening hours (and 100s+ J/kg in the overnight hours), and bulk shear values in the 30 to 40 knot range, severe storms cannot be completely ruled out, even though the chance right now is very small (<2%); the location with the best chance for severe weather late Tuesday is currently the far west. The cold front continues through the U.P. through Wednesday, as the rainfall marches eastward with the front. As the showers and storms associated with the front are exiting the eastern U.P. Wednesday afternoon, a secondary shortwave moving into the western U.P. behind the front could bring additional showers and thunderstorms back across the area behind it. The above normal temperatures we`ve been enjoying look to come to an end for the last half of the week as a low pressure settles over northern Ontario and sends cold air advection and multiple weak shortwaves across our area from late Wednesday through this next weekend. As this occurs, expect highs to drop into the 60s and for lows to get into the 40s, which is below normal for this time of year. In addition, light rainfall chances are expected from Thursday onwards due to the shortwaves rotating over our area; while we may see a rumble of thunder here or there during peak heating hours, given the cooler temperatures, thunderstorm activity should be less common. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 746 AM EDT Sun Jun 2 2024 Sfc high pres ridge will settle over the western Great Lakes today, resulting in light winds under 10kt and VFR at IWD/CMX/SAW. An approaching disturbance tonight may spread -shra into far western Upper MI late tonight. For now, confidence is low that IWD will be affected by any -shra. Only VCSH was included in fcst with VFR continuing. VFR will also prevail at CMX/SAW tonight. Ahead of the disturbance, low-level jet will reach western Upper MI late tonight, resulting in LLWS at IWD/CMX. && .MARINE... Issued at 323 AM EDT Sun Jun 2 2024 Light winds of 20 knots or less continue today into tonight as weak surface high pressure continues over Lake Superior. However, as a cold front moves through late tonight into Monday, southerly winds look to gust up to 20 to 25 knots Monday, particularly over the central lake and possibly near the south shoreline (especially near the tip of the Keweenaw, where higher wind gusts could be seen). Once the cold front moves through, the winds die down to 20 knots or less yet again by Monday evening as weak high pressure ridging sprints through the region. The light winds continue until a cold front from the Northern Plains passes west to east across the lake Tuesday night through Wednesday. Behind the front, expect southwest winds to gust up to 20 to 25 knots over the western half of the lake on Wednesday as a secondary shortwave quickly moves through the region. As a parent low sets up shop in northern Ontario for the latter half of the week, expect cold air advection and multiple shortwave lows rotating around the parent low to bring higher west to northwest winds across Lake Superior throughout the rest of the work week and into this next weekend; we could see westerly gusts up to 30 knots as soon as Thursday. As for other marine hazards, the fog over Lake Superior looks to burn off a few hours after the sunrise this morning as the sun warms the air. A few thunderstorms could be seen over the lake tonight through Monday night from west to east as the first cold front pushes through. The second cold front pushing through looks to bring a few more thunderstorms across the lake from west to east from Tuesday afternoon through Wednesday. No severe weather is expected at this time, although there is a very low chance (<2%) that we could see some severe weather over the far western lake Tuesday afternoon and evening. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Dense Fog Advisory until 8 AM EDT /7 AM CDT/ this morning for LSZ162-263-264. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...TAP AVIATION...Rolfson MARINE...TAP