Expires:No;;219862 FXUS63 KMQT 201751 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 1251 PM EST Wed Jan 20 2021 .SHORT TERM...(Today and tonight) Issued at 427 AM EST WED JAN 20 2021 Busy short term period today. With the northern stream of split flow at the mid-upper levels positioned across the northern conus, a robust shortwave will dig southeast into our neck of the woods this evening. At the moment, ridging building across the central plains is helping to increase subsidence and introduce some drier air into the west. This has cleared out skies and allowed surface temps to drop below zero in the interior west. Where the cloud cover and continued LES off Lake Superior have persited through the night, temps have remained largely in the teens. Looking upstream, GOES East water vapor imagery positions the shortwave moving into northern Montana and North Dakota, with southerly and southwesterly winds gusting ~35 mph along the isallobaric maxima. MSAS analysis has the 3 hour pressure change between -6 and -8mb in these locations. This maxima is progged to dip into our region this afternoon as the shortwave inches closer and the surface cold front moves into the west. There is a consistent signal in the 0z guidance of this maxima will maintain itself as the front moves through, perhaps being even a little stronger. Coupled with some low level instability and an expansive area of 35kts at 925mb, strong winds mixing down to the surface should make for a blustery day. CAMS are really hitting hard on strong winds along the Lake Superior shoreline in the east and downslope areas along the LLJ core axis. I incorportated some of that into this package. Overall, I'm expecting wind gusts approaching 30 mph across the entire forecast area this afternoon/evening. Terrain may help create some localized higher amounts, specifically downslope of the Michigamme Highlands into Marquette, Goegebic Range and the along the immediate lakeshores of Alger and Luce counties. Along these lakeshore locations, stronger 40-50mph winds are expected. Combined with the recent snow and potential additional light snow developing off Lake Michigan this evening, area's of blowing snow look likely. Elected to issue a winter weather advisory for these counties, including northern Schoolcraft, as lower visibilties and some drifting snow in exposed roadways appears likely. I also opted to issue a lakeshore flood advisory for Schoolcraft, as the strong southerly to southwesterly winds will help build waves 8-10 feet. Some areas, particlarly east of Manitsique could see some beach erosion or lakeshore flooding. This evening, winds will veer westerly as the surface low moves to just north of Lake Superior. With the strong pressure gradient lingering, stronger winds are expected in the Keweenaw. At the moment, some 35 mph gusts look possible, particiarly along the lakeshores. Ended up issuing another lakeshore flood advisory for Northern Houghton and the Keweenaw, as waves along the western lakeshore could build to 12 to 15ft. Elsewhere, the winds will slowly let off through the evening but still remain blustery along the lakeshores. In terms of precip, some lingering LES are expected in the east this morning. Through this evening, radar has observed these slowly shifting eastward as ridging builds into the region and winds become westerly and southwesterly. The airmass building in is pretty dry out and any forcings along the system's cold front will need to overcome this in order for any snow to occur. The exception is just upstream of Lake Michigan, where moisture flux from the lake combined with the theta-e and fgen should be enough to help squeek out some light snow. Some additional snow may linger after the front as 850mb temps remain near -10C. Another area that could see some snowfall is in the Keweenaw. There CAA this afternoon and evening will help sink 850mb temps back down to -10C. A combination of upslope enhancement and surface convergence could produce some snow showers in the west wind belts this afternoon and evening. Under this WAA regime, daytime temps will quickly warm up this morning, reaching the upper 20s to perhaps some low 30s being possible. Tonight temps won't fall to much and I'm expecting widespread 20s. .LONG TERM...(Thursday through Tuesday) Issued at 147 AM EST WED JAN 20 2021 Upper air pattern consists of a 500 mb trough over the upper Great Lakes 12z Thu. This trough remains into Friday and broadens. Troughing then drops into the northern plains by 12z Sat. Lake effect snow will continue to slowly wind down for this forecast period and this is already covered in the going forecast. Had to bump pops up to account for lake effect and this is the major change to this forecast. In the extended, the GFS and ECMWF show a 500 mb trough over CA and a trough across the Canadian Prairies 12z Sat. This Canadian trough heads into the northern plains 12z Sun. Troughing remains in the western U.S. 12z Mon and then heads into the Rockies on Tue and into the central plains on Wed. Temperatures warm to near normal for this forecast period with the storm track well to the south of the area. There is an Alberta clipper type system that quickly moves through on Sun and weakens. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1251 PM EST WED JAN 20 2021 Strong clipper-type low pressure system moving through Manitoba and Ontario will push a strong 50-60 kt LLJ across the area this afternoon leading to a period of LLWS at all terminals - worst at IWD. Gusts mixing down to the surface could lead to some blowing snow as well, but don't think there will be any significant vis reductions from BLSN this afternoon. Cold front moves through later this afternoon/early this evening with MVFR cigs moving in behind it at IWD and CMX. Strong gusty winds are expected overnight and tomorrow at CMX behind the front with 45 kt gusts possible. These stronger winds will also lead to an increase in BLSN so have dropped vis lower during this period at CMX. Second period of more marginal LLWS is expected at SAW behind the front as well. MVFR cigs reach SAW tomorrow morning and remain in place at all terminals through the end of the TAF period. && .MARINE...(For the 4 AM Lake Superior forecast issuance) Issued at 427 AM EST WED JAN 20 2021 Southerly gales are expected to develop this morning in the west half ahead of a robust shortwave and surface low thats moving into Ontario. These gales will spread into the east this afternoon. Gales of 40 to 45 kts are expected, and it should be noted that some higher storm force gusts are possible, particlarly offshore of the southern Lake Superior shoreline east of Marquette this afternoon and evening. Freezing spray will also be possible today lakewide. Winds will let off some and become westerly tonight behind the low's cold front and then become northwesterly Thursday morning. Gale force gusts to 35kts look to stay possible through Thursday. An arctic front is progged to dip into the region late Thursday. The colder air will once again make for freeing spray conditions with some heavy freezing spray is looking possible across the north central part of Lake Superior. Winds look to lighten to near 20kts Friday night through Saturday before increasing to 25kts in the east on Sunday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until 1 AM EST Thursday for MIZ006-007- 085. Lakeshore Flood Advisory from 9 PM this evening to 5 AM EST Thursday for MIZ001-003. Lakeshore Flood Advisory from 4 PM this afternoon to 1 AM EST Thursday for MIZ014. Lake Superior... Gale Warning until 10 AM EST Thursday for LSZ245>251-265>267. Gale Warning until 7 AM EST /6 AM CST/ Thursday for LSZ162- 240>244-263-264. Lake Michigan... Gale Warning until 1 AM EST Thursday for LMZ221-248-250. && $$ SHORT TERM...JP LONG TERM...07 AVIATION...RJC MARINE...JP