471 FXUS63 KMQT 090644 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 244 AM EDT Sat Oct 9 2021 .SHORT TERM...(This evening through Saturday) Issued at 345 PM EDT FRI OCT 8 2021 If you have gone outside today so far, you will notice that it is unseasonably warm, and humid outdoors. While this is certainly not unheard of for the first week of October in Upper Michigan, the fall foliage doesn't match the observed weather pattern presently. Satellite imagery as of 19Z this afternoon shows the low stratiform cloud cover beginning to wane over the west half, and even a few areas seeing peaks of sunshine. Dew points in the lower to middle 60s combined with surface obs in the middle to upper 60s make a good case of why the low clouds and fog were present for a majority of the day thus far across the area. Abundant moisture advection continues to occur over our area as the broad surface low pressure over the Lower Great Lakes funnels in higher dew points from the southeast CONUS. GOES WV analysis shows abundant moisture aloft, with a narrow band of dry air remaining to the east as the stacked upper level low circulates over southern Lake Michigan this afternoon. For those that have been following the weather patterns over the last week or so, the present occluded ULL is the remnants of what we had over our area last weekend that resulted in fog, drizzle, and low clouds. This ULL moved from the Great Lakes to the Southeast CONUS, and then slowly became absorbed with the main upper level flow the past couple of days as it retrograded further to the north-northwest over the Great Lakes once again. All of that being said, this slow-moving weather system will slowly trek to the north and northeast for the short term forecast, resulting in scattered showers across Upper Michigan, which has been observed throughout the day thus far on radar. Areas that have partial clearing in sky coverage could see a brief heavier rain shower, and perhaps a rumble of thunder. Although, SPC Mesoanalysis shows very little with regard to instability across the area...less than 500 J/kg. Marginal lapse rates of 5-6 degrees C/km are present, mainly along the WI/MI border. Without a strong forcing mechanism, the expectation is that a majority of areas will see brief rain showers, and very little to no thunder. For tonight, moisture advection will continue to be funneled into the area courtesy of the occluded ULL. With WAA at 850mb also, the warm temperatures will not be disappearing. Elevated dew points close to surface temperatures overnight will result in very low cloud cigs, and patchy fog across several areas of Upper Michigan. Especially in locations that see rain showers. Expect overnight lows to drop down to the upper 50s to low 60s. It will be an unseasonable warm and muggy night. Saturday will see low clouds slowly erode as rain showers push to the east through morning into the early afternoon. Partly cloudy skies are likely for the west half as zonal to weak ridging aloft at H5 occurs from midday Saturday through the late afternoon. This will help temperatures elevate slightly into the upper 60s to lower 70s. Went with a conservative blend of temperatures for Saturday, but a couple of Hi-res members do hint at temperatures across the interior, and near the northern lakeshores reaching the low to middle 70s due to downslope effects from weak southerly winds. However, the expectation is that cloud cover will be slow to erode away, so went with highs near 70 to the lower 70s for most areas. With the elevated dew points remaining across the area near 60 for Saturday, the muggy conditions will remain across the area also. The break in any cloud cover will be short lived for the west half as the next weather system approaches from the Upper Midwest late Saturday evening, resulting in another round of cloud cover approaching Upper Michigan. .LONG TERM...(Sunday through Friday) Issued at 243 AM EDT SAT OCT 9 2021 As the remnants of the Rex Block low shift NE into Quebec on Sunday morning, attention then turns to a more progressive pattern through the rest of the longterm period. In general, large scale troffing will be present across much of the wern CONUS as downstream ridging and positive height anomalies will be present through the Great Lakes and ern CONUS, extending well to the north over Hudson Bay. This pattern will set up an active storm track over the central portions of the CONUS as 3 separate waves lift through the Plains. The first will be on Sunday as a sfc low lifts through northern MN bringing sct showers and an isolated thunderstorm chance across the UP. As the first wave exits, another moves in behind it on a track slightly to the east of the first. This will bring another chance of widespread showers Monday night into Tuesday. The third wave ejects from the Rockies on Tuesday night as sfc low deepens across the Central Plains Wednesday morning...lifting through the Northern Plains by Wednesday evening. This system will bring some pcpn and wind across the UP, but the larger impacts will likely remain off to our west in the Dakotas and MN. All of this will occur while temperatures remain above normal through the extended period. A shrtwv and assoc sfc low will be over northern Minnesota on Sunday morning as some sct shra will begin moving back into the UP from the SW. This low will be on the slower side as it progresses into northern Ontario by Monday morning. As WAA and isentropic ascent increase Sunday morning along 35 to 40 kt 850mb winds some elevated instability increases. Instability remains conditional with there being some inhibition and capping on model soundings; however, MUCAPE is closer to 1000 J/kg with decent mid-level lapse rates near 7.5 to 8C/km. The best ingredients appear to the west and over Lake Superior with decent ingredients remaining over the western half of the UP in the afternoon. Svr chances are unlikely, but with bulk shear near 40-45kts and decent mid-level lapse rates, hail would be the primary threat. This first system exits early Monday morning, which will leave a cloudy, but dry Monday across Upper Michigan. The next system in line will begin lifting through the Central Plains on Monday aftn, reaching the UP late Monday into early Tuesday morning. The best chances for pcpn with this system will be across the central and ern portions of the UP, where the southerly flow and dewpoints will be the highest. As this system will be weakening as it moves through, winds won't be a concern and the only thunderstorms chances will be slight and off the east half along the LLJ. Attention will then turn to the last system of this weekend that looks to mainly impact locations to our west across the Northern Plains. A wave is expected to eject out of the Rockies on Tuesday aftn before lifting north as a leeside low develops over the Dakotas by Wednesday morning. A pcpn shield associated with this system will remain to the north of the low over the Dakotas and MN as the UP picks up some trailing pcpn along and ahead of the cold front. A more seasonable airmass is progged to move in behind the exiting system to end the week. With 850mb temps around 0 to -2C, will probably some clouds and perhaps a lake-effect rain shower or two. These temps will likely not linger too long as medium-range ensemble means suggest another ridge to build back in across the central CONUS, meaning more above-normal temperatures expected. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 121 AM EDT SAT OCT 9 2021 Fog/stratus continue to be an issue under persistent warm/humid conditions for this time of year. At IWD, bkn clouds around 4000ft will likely scatter out at some point overnight, allowing fog/stratus and IFR conditions to develop toward daybreak. Expect improvement to VFR by aftn. At CMX, similar to recent nights, light easterly upslope winds have resulted in LIFR conditions, even blo airfield land mins, to develop. Overnight, low-level winds should swing around to the ssw, favoring improvement. However, winds are very light, so LIFR conditions may linger thru the night. Opted to delay improvement until after sunrise for this fcst issuance, but improvement could occur sooner. VFR conditions should then prevail thru the aftn. At SAW, light upslope sse wind will support LIFR conditions thru the night. Expect improvement to IFR late Sat morning, then to MVFR, maybe VFR, in the aftn. Will likely see cigs fall back to IFR again this evening. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 224 PM EDT FRI OCT 8 2021 A broad area of surface low pressure will slowly move through the region today and Saturday, with winds from the east and southeast of generally 15 kts or less through Saturday evening. The forecast still continues to trend this weekend toward another surface low pressure moving from the Central Plains to the northeast into far western Ontario by Sunday. The surface low is forecast to remain north of the lake causing wind gusts from the SE at 20-30 kts on Sunday, mainly on the east half. Gale force gusts may be possible on the east half, followed by a period of WSW winds around 20 kts Sunday night and Monday, mainly on the west half. Light winds should return for Monday night through Wednesday afternoon. Another weather system will approach the Great Lakes on Wednesday night, bringing the opportunity for wind gusts of 20-25 kts across the lake. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...BW LONG TERM...JAW AVIATION...Rolfson MARINE...BW