553 FXUS63 KMQT 132245 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 645 PM EDT Wed Oct 13 2021 .SHORT TERM...(This evening through Thursday) Issued at 429 PM EDT WED OCT 13 2021 Water vapor imagery and RAP analysis show troffing over the western U.S. with a potent shortwave lifting across SD. At the sfc, associated 989mb low pres is located over n central SD with occluding front arcing se across sw MN and IA then southward from there. Solid shield of shra/tsra in advance of the front early today has largely dissipated while approaching Upper MI. More shra/tsra are developing in northern and eastern MN. Closer to home, it's been generally a cloudy day across the fcst area. Due to the clouds, temps have not risen much from this morning's lows. Current readings are generally in the low/mid 60s F. As the low over the Dakotas continues lifting nne tonight, occluding front will pivot ne across the fcst area. Best deep layer forcing will pass by to the w and nw of Upper MI. In addition, despite rather strong low-level wind fields (850mb winds up to around 45kt), isentropic ascent is rather weak and not strongly focused due to the weak thermal gradient across the Upper Great Lakes. As a result, pcpn coverage tonight should be no more than isold to sct in association with the fropa. Many locations shouldn't see any pcpn at all. Above the stable low-levels, there is sufficient instability (MUCAPE of 200-500j/kg in the 1-3km layer) to maintain a mention of tsra. SE sfc winds will increase this evening, but low-level stability will keep winds in check. One supporting factor for the wind increase will be the pres falls of 5-6mb/3hr currently across northern MN. Although the pres falls will be weakening while lifting n, they will aid some wind increase. Expect gusts to 20-30mph for a time at most locations. Gusts could be locally higher in the downslope areas of the Keweenaw. Mid-level drying will surge into the area after fropa, setting the stage for a mostly sunny day on Thu. SW winds will keep any moisture off Lake Superior from aiding stratocu development across the fcst area. Some lower level moisture will rotate into the western fcst area on the se side of the system lifting n and ne vcnty of the Manitoba/Ontario border, so expect some stratocu development far w during the day. 850mb temps will range from 3C w to 12C e to start the day. By late aftn, little change will occur w while temps fall slightly to about 10C e. This should support highs around 60F w to the upper 60s F. Temps could reach 70F or so e, but sw winds up Lake MI should temper warming a bit from what it could be. .LONG TERM...(Thursday night through Wednesday) Issued at 345 PM EDT WED OCT 13 2021 The streak of unseasonably warm weather transitions to near normal temperatures Friday through this weekend. This cooler air mass seems likely to produce lake effect rain across the eastern CWA Saturday into Sunday. Drier air moves in later Sunday associated with a building ridge that brings a return of above normal temperatures early next week. The next trough approaches the area late Tuesday into Wednesday, but sensible weather impacts are unclear at this time. A seasonably strong surface low will be positioned to our northwest Thursday night as a secondary surface low develops over the Southern Plains. This surface low rapidly lifts northeast toward Detroit on Friday, but should track far enough south to avoid precipitation with this system. A much cooler air mass with 850 mb temps around 0C flows in behind this system on Friday night. Record warm lake average temperatures around 15C result in inversion heights up to around 700 mb. This is more than adequate for lake effect rain showers for areas favored in WNW flow, especially across the east. Drier air moving in on Sunday effectively ends lake effect precip as the surface ridge axis moves overhead. This ridge axis shifts east Monday into Tuesday providing a couple days of nice and sunny weather. The next trough and associated surface low approaches from the west late on Tuesday. A quick peak at day seven WPC cluster analysis shows ensemble guidance is almost evenly split. The variety of possible solutions ranges from a closed low directly overhead to a subtle shortwave embedded within an expansive ridge. Based on the past year of weather it seems wise to favor the warmer/drier solutions, but maybe this system will be the straw that broke the camel's back? Only time will tell. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 644 PM EDT WED OCT 13 2021 Changeable conditions are expected this fcst period. There may be a few shra, perhaps tsra, ahead of the front, but confidence in any of the terminals being impacted is low. Winds will also become gusty to 20-30kt this evening with gustiness continuing into Thu in general. At IWD and CMX, VFR remain for most of the forecast period. At SAW, MVFR cigs should prevail thru this evening before improving to VFR by daybreak. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 429 PM EDT WED OCT 13 2021 As strong low pres lifts nne through the Dakotas into southern Manitoba tonight, e to se winds will increase. Expect winds up to 30kt. A few gale force gusts to 35kt are possible w this evening and e during the early part of the overnight period. Front associated with the low will sweep across Lake Superior late tonight and Thu morning, bringing a wind shift to the sw. These sw winds up the w half of Lake Superior should continue to gust up to 30kt thru Thu. A few gale force gusts to 35kt will be possible. To the e, winds will diminish some with gusts lowering to around 20kt on Thu. W to sw winds will gust to 20-25kt Fri, strongest again w half. As a more seasonal air mass arrives over the lake this weekend, w to nw winds should frequently gust to 25-30kt. Could be a few gale force gusts to 35kt Sat night. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...EK AVIATION...07 MARINE...Rolfson