Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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129 FXUS63 KMQT 111749 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 149 PM EDT Sat May 11 2024 .KEY MESSAGES... - Light rain showers end from west to east this morning. - Could flirt with borderline fire weather conditions near the Wisconsin border late this afternoon as min RHs dip to around 30%, northwest winds could gust up to 20 mph at times, and high temperatures could get to the low to mid 60s. - Scattered thunderstorms to develop Sunday afternoon, especially south central. There is a low chance (2%), for marginally severe hail and/or wind. - Dry weather returns by Monday, continuing through Wednesday afternoon. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 240 AM EDT Sat May 11 2024 With some breaks in the clouds, some of us were able to see the Aurora Borealis over us this past evening into very early this morning from time to time, including us at the forecast office here in Negaunee Township. As the low pressure now over northern Lake Michigan continues to spin away from the area today and high pressure ridging moves in from the northwest, skies clear out and the light rain showers cease. The rain showers are looking to be limited to the far eastern U.P. (Chippewa and Mackinac counties) by the early afternoon hours as the ridging builds in. However, a few upslope sprinkles from the modest northwest flow could be seen over the highlands of the Keweenaw and the north central U.P. from time to time until the middle of this afternoon. In addition, the Euro is wanting to bring some sprinkles over the south central this evening. However, with hires model soundings showing an inversion up to 4-5 kft by the mid afternoon hours over the south central, any rain droplets hitting the ground seems very doubtful (90+% of being precip-free this afternoon). With mostly sunny skies across the U.P. by the mid-afternoon hours and slight warm air advection occurring throughout the day, thinking the high temperatures will be in the low to mid 60s over the interior west half and the 50s in the east and along the lakeshores. While winds aren`t expected to be all that impressive today, we could see some northwesterly gusts up to 20 mph in the interior areas by the afternoon hours today. With min RHs looking to get down to around 30% near the Wisconsin border, we may flirt with borderline fire weather concerns late this afternoon in the interior west. && .LONG TERM /TONIGHT THROUGH FRIDAY/... Issued at 419 AM EDT Sat May 11 2024 Starting dry tonight as a weak sfc high pressure over the UP and the mid level trough over the Lower Great Lakes both depart southeastward. Another trough to the north moves east along northern Ontario. This northern trough sends some weak shortwave energy over the lake superior. With the support of WAA and isentropic ascent, light showers spread east, mainly over the west half of the UP. Chances for showers increase in the afternoon as a cold front associated with a sfc low to the north passes southeast over the area. With the timing of the cold front in the late afternoon, peak daytime heating will help fuel some showers and thunderstorm development, especially over the south central UP. Highs will be above normal climbing into the upper 60s to mid 70s save for the east where southerly winds off Lake Michigan keeps the area cooler in the mid 50s to low 60s; the Keweenaw should see low to mid 60s. While moisture is not terribly high with dewpoints only in the the mid to upper 40s, lapse rates will be pushing near 9C/km with mid level lapse rates around 7C/km which should yield enough buoyancy. The 5/11 0z HREF mean SBCAPE is around 250-750 j/kg with higher models such as the GFS/NAM plotting up to 1000 j/kg mainly along the WI/MI state line (especially near south central Upper MI). That accompanied by an HREF mean bulk shear of around 45 kts leaves the potential for isolated severe storms with the main threats being hail and winds. This stronger thunderstorm development also depends on the previous precip and lingering cloud cover. Chances for thunderstorms diminish Sunday evening with dry weather returning to all the UP by around midnight. A secondary cold front is progged to pass over the UP Sunday night with really no impacts beyond slight wind shifts and increased cloud cover. Dry northerly flow behind the cold front accompanying a sfc high pressure will keep dry conditions through Wednesday afternoon as the mid level trough slowly meanders east toward Quebec and another shortwave trough makes its way from the Plains to the Appalachians. This will yield a few days of sunny skies, better mixing, and drier RHs nearing 30%. Lake breeze interactions are also likely with the high pressure extending overhead, helping keep cooler conditions by the lakeshores. Highs look to be in the upper 50s to upper 60s in the interior next week. Upper 40s to mid 50s by the lakeshores early next week increase to mid 50s to low 60s by Friday. Lows are forecast to increase from their coldest Monday night in the 30s to low to mid 40s by the end of the work week. Chances for showers and possibly some thunderstorms increase late Wednesday night/Thursday onward as we track out the next trough to move along the Canadian/U.S. border toward the Great Lakes. With significant differences in the model guidance on track and timing, opted to leave the NBM chance PoPs alone beyond Thursday. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 149 PM EDT Sat May 11 2024 VFR conditions will prevail thru this fcst period at IWD/CMX/SAW. As low pres drops into far northern Ontario tonight, a low-level jet will develop into Upper MI late tonight into Sun morning, resulting in 2-6hrs of LLWS at all terminals, lasting longest at IWD. The low- level jet will also generate sct -shra, but confidence in a shra passing over any of the terminals is low. Not expecting conditions to drop out of VFR if a shra does occur. More shra/possible tsra will develop Sun aftn across central Upper MI, possibly affecting SAW. && .MARINE... Issued at 419 AM EDT Sat May 11 2024 Winds are mainly expected to mainly remain below 20 kts through the entire forecast period. However, the best chances for wind gusts to around 20-25 kts is expected Sunday night as an approaching cold front tonight increases southerly winds, stronger over the east half where the pressure gradient is tighter. That being said, the strongest winds are mostly limited to the higher observing platforms due to the stability within the chilly marine layer. The cold front does bring a slight chance for thunderstorms along the southern nearshores Sunday afternoon. Then on Monday, high pressure begins building over the lake. This weak high pressure continues through mid week before moving northeastward into Canada keeping light winds and dry weather in the forecast. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TAP LONG TERM...Jablonski AVIATION...Rolfson MARINE...Jablonski