Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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487 FXUS63 KMQT 100845 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 445 AM EDT Mon Jun 10 2024 .KEY MESSAGES... - Chilly and dry again tonight with high pressure overhead. Patchy frost is possible. - A more active period is expected Tuesday afternoon through Thursday night. This will be accompanied by generally warmer than normal temperatures that continue into the weekend. && .SHORT TERM /TODAY/... Issued at 443 AM EDT Mon Jun 10 2024 Water vapor imagery/surface analysis early this morning shows yesterday`s low pressure system now on the east Canada coast, while high pressure strengthens over the Prairie Provinces and Ontario. This puts Upper Michigan under clear skies and light winds with some radiational cooling mainly over the interior west where temperatures are currently in the low to mid 30s. Elsewhere, temperatures have been slow to drop this morning with ground-based obs generally reporting low to mid 40s over the remainder of the forecast area. So, any patchy frost is expected to be minimal this morning and concentrated over the interior west. With plenty of sunshine, though, temperatures will reach the upper 60s later today. The exceptions will be the eastern Lake Superior shores and Keweenaw, which will struggle to climb any higher than the 50s and lower 60s, respectively. Meanwhile, with the dry airmass and some gusty winds up to 20-25 mph (mainly east), wildfire conditions will be elevated. But, recent rainfall will help to mitigate the threat. && .LONG TERM /TONIGHT THROUGH SUNDAY/... Issued at 440 AM EDT Mon Jun 10 2024 Mid level ridging and sfc high pressure will be shifting over the Upper Great Lakes tonight, continuing the dry period. Near calm conditions, PWATs ~0.35" (below the NAEFS 10th climatological percentile), and clear skies sets up the UP for another radiative cooling night. Lows are expected in the mid 30s to mid 40s, warmer near the lakeshores. This leaves some potential for patchy frost. Meanwhile, midlevel troughing will be approaching from the west. Tuesday through Tuesday night, a mid level trough moves east from Manitoba to Ontario, with pretty robust positive theta-e advection out ahead of it as southerly flow tightens up. A shortwave rotating around the trough from southern Manitoba to far northern Ontario will support the sfc low along a similar track. Resulting isentropic ascent, coupled with some weak PVA rippling out ahead of the approaching trough, could touch off some showers and storms across the western UP as early as Tuesday afternoon. However, most convection holds off until the evening as the associated cold front moves through. With latest model guidance indicating bulk shear ~30 kts and not much CAPE by then (6/10 0Z LREF mean CAPE around 50- 100j/kg with a max of 400 J/kg), strong storms are not likely and severe storms are not expected as the cold front moves through. As the cold front and isentropic ascent weakens Tuesday night, showers and any storms begin to diminish as they continue eastward across the UP. Dry weather returns to the west half around midnight. Wednesday likely should see mostly dry weather until the afternoon. WAA from low level southwest becoming south flow will help bring warmer than normal temps into the 70s with some spots in the interior west possibly reaching into the low 80s. Some diurnal showers and storms are possible as we reach convective temps, mainly in the east and along Lake Superior where there could be some support from a lake breeze and/or weak PVA from the trough moving east through northern Ontario. Bulk shear will be ~40 kts with the 6/10 0Z LREF plotting mean CAPE of around 300-500 J/kg; the NAM is the strong outlier with up to ~1000-1500 J/kg of CAPE. Some stronger storms are possible if the NAM setup is favored, but with uncertainty in forcing and location of showers/storms, left as slight chance PoPs (15-24%) for now. A sfc low over southern Manitoba tracks east to just north of Lake Superior Wednesday night into Thursday. While there still is some significant spread in the model guidance thanks to poor resolution of the mid level trough, this sfc low is expected to bring a cold front across the area into Thursday morning bringing additional chances for shower and storms. This will quickly be followed by a southerly push of the mid level trough through Thursday night, likely yielding the last chances for showers and storms this work week. There is some agreement on ridging with sfc high pressure moving over the area for the early part of the weekend, but as this starts to slide east out of the Upper Great Lakes late in the day Saturday through Sunday, some PoPs do sneak in. Given uncertainty regarding timing this far out, opted to leave NBM PoPs as is after Friday. Temperatures will feel more summer-ey the rest of the week, with highs ranging well into the 70s for most of the area Thursday through Sunday and lows in the 40s and 50s. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 111 AM EDT Mon Jun 10 2024 Skies have cleared across the UP with clear skies expected to prevail through the entire TAF period. There is a chance of fog for IWD, though. Light north winds prevail but light and variable winds are possible at CMX/IWD this morning and at SAW this evening as a high pressure ridge slides across the area. && .MARINE... Issued at 440 AM EDT Mon Jun 10 2024 With high pressure over Lake Superior through Tuesday morning, winds are mainly expected below 20 kts. The exception to this would be for some channeling northwest winds in whitefish bay, possibly gusting up to 25 kts. The next potential for winds to exceed 20 kts is Tuesday night into Wednesday over the west half of the lake when a low pressure system tracks through far northern Ontario. That said, chances of winds exceeding 20 kts are low (20-40%) given the stability over the lake. Another low pressure system tracking just north of Lake Superior Wednesday night through Thursday brings similar chances for the eastern half of the lake. High pressure returns calmer conditions below 20 kts for the start of the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TDUD LONG TERM...Jablonski AVIATION...EK MARINE...Jablonski