059 FXUS63 KMQT 150042 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 842 PM EDT Wed Oct 14 2020 .SHORT TERM...(This evening through Thursday) Issued at 348 PM EDT WED OCT 14 2020 Latest RAP analysis, GOES Satellite, and Hi-res guidance showing a closed surface low of 997mb over the Northern Plains. This low is moving along the base of an upper-level low seen at 500mb, located over the Hudson Bay. This low still has a negative tilt to it and will dig a bit, which will help strengthen the surface low through the rest of the day and into tonight, bringing another round of rain and gusty winds. Once the low passes, caa will usher in the colder air, allowing lake-effect precip to form over the northwest wind belts with winds turning from the southeast to the northwest. Some CAMs are trying to hold onto some precip chances out east Thursday afternoon and latest 12z runs are hanging onto some Lake-Effect rain out east. With the blustery northwest winds, there is the concern of some Lakeshore Flooding east of Marquette along Lake Superior. Ahead of this surface low approaching, GOES satellite shows that cirrus shield moving across the UP and with a decent mid to upper level jet of 130+ kt (a little lower from the previous discussion), plenty of fgen with the warm sector of the low will help maintain these showers through the rest of the afternoon and evening. There will be a brief period of dry weather before the cold front swings through later tonight. Depending on how long the dry stretch is, there is decent mixed layer which could help aid some gusty southeast winds, especially over the east and along the Lake Superior shoreline with downsloping. With the dry slot, some CAMs are trying to indicate more rain showers mainly over the west. An isolated thunderstorm can't be ruled out but given the fact I didn't think thunderstorms would occur yesterday, would not surprise me if the same thing happened again over the west because 2020. In wake of the cold front passing, winds will become blustery from the northwest, which will trigger Lake-Effect rain, possibly mixing with snow with 850mb temps getting down close to -7C but drier air moves in by early afternoon which should be enough to cut off the Lake- Effect and if any occurs, more likely it will be in the form of rain. Lake-Effect rain showers could linger over the east through Thursday afternoon. With the onset of blustery northwest winds, went ahead and issued a Lakeshore Flood Advisory for Alger and Luce Counties as minor Lakeshore Flooding and Beach Erosion is likely. Temperatures this afternoon should remain mostly in the 40s with a few 50s south-central. Did tweak temperatures a couple degrees cooler as Hi-res guidance was trending a bit cooler with clouds lingering with dry slot moving in ahead of cold front. Lows tonight should remain mostly in the 30s as clouds won't clear out as much as last night. Thursday will have almost a late fall feeling with highs in the 40s but with blustery winds, will feel colder than that. .LONG TERM...(Thursday night through Wednesday) Issued at 345 PM EDT WED OCT 14 2020 Active pattern continues in the long term as deep troughing extending south out of a mid-upper level low over northern Manitoba looks to park itself over the Upper Great Lakes. This trough will allow cold air to sink south into the region, giving the Upper Great Lakes a period of below normal temperatures. Additionally, this cold air will set off some lake effect precip Thursday night and Friday. Attention will then turn toward a potential stronger storm at the base of the next trough axis this weekend. Beginning Thursday night and Friday, with the early Thursday low northeast of the region, the next shortwave pivoting through the base of the trough axis should be over the forecast area early in this period, helping to kick off a round of light precip. 850mb temps look to be around -6 to -8C and with lake temps hovering around 8C, the instability should be enough for some lake induced showers to continue, mainly in the west wind belts overnight. Precip type does look to be primarly snow given the sufficient lift and moisture within the DGZ, as well as low wetbulb zero heights. Soundings also highlight inverions near 10k ft and a low directionally shear'd environment, but also a healthy low level dry layer near the surface. Given this dry layer, confidence is low that much, if any, accumultion will be realized. Overnight lows should drop into the 20s for regions away from the lakeshore. The timing of the next shortwave looks to be Friday afternoon. Similarly to the Thursday evening/night shortwave, the lake effect parameters are there, but given the low level dry layer, I'm skeptical about much, if any accumulation. Day time highs should climb into the 40s, with mid-upper 40s in the east and low 40s in the west. Overnight Friday looks to be dominated by slight surface ridging, which should help keep mostly clear skies for most of the overnight period. This will allow lows to dip down in to the low 20s for many in the west and mid 20s elsewhere, except by Lake Michigan where low 30s are possible. I wouldn't be surprised if some of the traditionaly colder locations ended up in the high teens. By sunrise, cloud cover will begin filtering in the west ahead of the next system. Guidance appears to have a good handle on the progression of the next low. Timing among the determinisitics and ensembles bring the low through the region Saturday night, with precip spreading over the region beginning Saturday afternoon. In terms of precip type, increasing WAA ahead of the low should help transition any early snow or rain/snow showers over to all rain for a period. Immediately following the low, increasing CAA may switch back ptypes to rain/snow mix or pure snow as well as induce some lake enhancement. Similarly to today's sytem, the low appears to be influnced by left exit jet dynamics, which will help deepen the system as it transits through the Upper Great Lakes. As the pressure gradient tightens, the increasing southerly winds may spell some lakeshore flooding or beach erosion concerns for Lake Michigan lakeshores. As we get closer to this event, these details will be ironed out. Beyond this, the guidance diverages on the pattern, with the GFS and Canadian presenting a solution with the gradual lifting of the mid- upper level low followed by zonal flow. This contrasts with the EC, which highlights an amplifed pattern with deep troughing over the west and ridging in the east becoming established. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 820 PM EDT WED OCT 14 2020 KIWD and KCMX...VFR conditions early this evening will quickly lower to MVFR and perhaps even briefly to IFR late this evening into the overnight hours as lake enhanced/lake effect showers move in behind the passage of a cold front. Northwest winds will also get quite gusty behind the front with gusts over 30 knots at KIWD and over 35 knots at KCMX late tonight into early Thu. Expect gradual improvement in conditions through Thu at both sites perhaps even improving to low-end VFR late in the day as drier air works in from the low-levels. Northwest winds will also diminish by late Thu as the low pressure system affecting our area tonight lifts off into Quebec. KSAW...IFR conditions at KSAW will briefly improve to VFR this evening but then lower again to MVFR late tonight as a stratocu deck moves in behind the cold frontal passage. Expect gusty northwest winds of 25-30 knots to kick in late tonight and then continue through much of the day on Thu. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 348 PM EDT WED OCT 14 2020 Still looking like an active period across the lake for this forecast period with multiple gale events to highlight. First is the southeast gales for the east half tonight. Winds up to 40 kts through the evening hours. There will be a lull tonight as a low pressure will move across the lake with a cold front moving across, switching the winds coming from the northwest leading to next gale event after midnight tonight into early Thursday. Winds over the west half will be between 35-40 kts while the east half will see winds 40-45 kts with waves up to 16 ft. With this, did not change headlines from overnight shift and agreed to keep east half under continuous Gale warning through late afternoon Thursday. Winds will finally relax to under 20 kts by late Thursday into Friday. Next system approaches Saturday afternoon into Sunday as models coming into good agreement on timing but not strength of winds. For now expect southerly winds between 20-30 kts with some gale force gusts Saturday night then becoming northwest gales over east half Sunday morning as system passes through before subsiding. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Lakeshore Flood Advisory from 7 AM to 6 PM EDT Thursday for MIZ006-007. Lake Superior... Gale Warning until 4 PM EDT Thursday for LSZ249>251-266-267. Gale Warning from 3 AM to 2 PM EDT Thursday for LSZ245>248-265. Gale Warning from 1 AM to 11 AM EDT Thursday for LSZ243-244-264. Gale Warning until 9 AM EDT /8 AM CDT/ Thursday for LSZ162- 240>242-263. Lake Michigan... Gale Warning until 11 AM EDT Thursday for LMZ221-248-250. && $$ SHORT TERM...JH LONG TERM...JP AVIATION...Voss MARINE...JH