FXUS63 KAPX 040755 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 255 AM EST Wed Dec 4 2024 .KEY MESSAGES... - Lake effect snow combined with gusty winds on the backside of a clipper system will bring about continued higher end travel impacts to the snowbelt areas of northwest lower and eastern upper Michigan. && .SHORT TERM /THROUGH TONIGHT/... Issued at 255 AM EST Wed Dec 4 2024 ...More accumulating snow along with windy conditions on the way... Widespread synoptic snow has developed across our entire CWA early this morning well in advance of the approaching strong clipper system...which is now centered over Western Ontario. Dominant SW flow lake enhanced snow band embedded within the synoptic snow shield continues to stream into the Straits area as expected... dumping warning criteria snowfall from Leelanau county thru Western Charlevoix to Emmet and Cheboygan and across portions of Eastern Upper Michigan. All of the above areas are under a Winter Storm Warning thru today and into early this evening....where 5 to 10 inches of new snow is expected. Little will change during the morning hours as low level SW flow persists...targeting the above outline areas withing the Straits for the most persistent and heaviest snow shower activity. Total morning new snowfall will be 5 to 10 inches within this area...and will therefore leave all Winter Storm Warnings in tact. Rest of our CWA will see light to at times moderate snowfall thru the morning...with a general 1-3 inches of new snow expected. Winds gusting to 30 mph will cause areas of blowing and drifting snow as well. Initial cold front associated with the clipper system will sweep thru our CWA this afternoon into early evening...shifting low level flow to the NW. CAA will commence behind the initial cold front... reinforcing ongoing over-lake instability and thus lake snow production...but will refocus the most persistent and heaviest snow showers into our typical NW flow snowbelt areas. A secondary cold front will drop thru our CWA late tonight...shifting winds to a more N/NW direction...which will likely shift the focus for heaviest snowfall to areas along and west of US-131. Very tight pressure gradient behind both the initial and the secondary cold front will translate to winds gusting to 30 to 40 mph at times...producing areas of blow and drifting snow and certainly hazardous travel this afternoon thru tonight. All in all...expect new snow amounts for our NW flow snowbelt areas of 5 to 10 inches this afternoon thru tonight. Will therefore issue Winter Storm Warnings for all counties along and west of I-75...and Winter Wx Advisories for much of NE Lower Michigan where 3 to 5 inches of new snow along with blowing/ drifting snow is expected thru tonight. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 255 AM EST Wed Dec 4 2024 Pattern Synopsis / Forecast: Clipper system will be exiting the region through the day on Thursday, though with continued overlake instability and lingering strong NNW flow, lake effect snows will be continuing across parts of the region. Eventually, as the surface low moves east and surface high pressure intrudes into the Corn Belt, the pressure gradient slackens, thus reducing flow over the lakes, and more importantly, diminishes available moisture to produce efficient lake effect snows Thursday night into Friday. The influence of the surface high pressure will keep things a bit drier (with some continued lighter lake effect Friday), but on its heels, another clipper system will be moving toward the Great Lakes, which looks to pass through Friday night into Saturday, and another into Saturday night. The colder pattern then moderates owing to the influence of a progressively more northerly clipper track with these systems, drawing in warmer air by the end of the weekend. Eventually, a baroclinic zone looks to set up next week, but with ample uncertainty to the evolution of any potential systems moving into the region. Primary Forecast Concerns: At the start of the period, efficient NNW flow lake effect snows will be ongoing, with the most efficient region being spots downwind of Grand Traverse Bay, which could see an additional 3-6"+ of accumulation through the day Thursday. Elsewhere, perhaps an additional few inches will be possible (lesser chances of additional snow closer to Saginaw Bay and east of I-75 in the eastern U.P.). The issue with Thursday will be focused on winds in other areas. There will be ample fresh, fluffy snow that will be primed to be blown around by those continued 15-25mph sustained winds, and gusts of 30-45mph (locally higher near Lake Michigan), especially during the morning hours when the strongest cold air advection overhead supports efficient mixing and momentum transfer across the region. Result will be continued snarled travel at the very minimum for the Thursday morning commute across the snowbelts and other areas that have snow cover to be blown around... with the snowbelts likely seeing continued dangerous travel conditions Thursday due to whiteouts and drifting snow, especially in open areas. Eventually, the flow weakens later in the day into the overnight hours Thursday, which should lower lake effect intensity, and confine it well within those snowbelts. Additional lake effect snows will be possible Friday as winds back more westerly, shifting the focus of lake effect (albeit, a rather lighter intensity) to the W to WNW flow snowbelts, though at this juncture, there isn't much of a signal for more than a couple additional inches through the day Friday. Eventually, a second clipper passes through Friday night, and shifts winds more southwesterly, which could put more lake effect into the Straits. As of now, this system does not appear to be as intense as the one passing through over the next 24-48 hours, but nonetheless, will still be able to produce snow for the Straits and the eastern Yoop as synoptic snows build in there, while most places south of M-72 hold drier. Furthermore, as milder air is drawn in by these systems, it is possible for immediate lakeshore areas to see rain mix in at times Saturday night into Sunday. Looking into next week, the pattern is prime for a larger southern stream system (as opposed to a clipper) to pass through from the southwest, and with milder air in place, may lead to p-type issues. At this time, guidance is signaling it as a warmer system with rain potential as temps raise into the 40s. Eventually colder air is set to build in behind this system, but uncertainty remains on how quickly that occurs... though signals do indicate the milder temperatures should take a reprieve around or slightly before midweek. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1147 PM EST Tue Dec 3 2024 Clipper low pressure system will bring increasing coverage/ intensity of SHSN overnight. PLN/CIU will the worst of it tonight, becoming IFR to LIFR at times. TVC/MBL become IFR by late tonight, APN becomes IFR Wednesday. Snow-liquid ratios in the mid teens. Sw winds become quite gusty tonight, veering w and wnw by late Wednesday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...Winter Storm Warning until 7 PM EST this evening for MIZ016- 017-087-088-096-097. Winter Weather Advisory until 7 PM EST this evening for MIZ018- 023-024-029-030-035. Winter Storm Warning until 7 PM EST Thursday for MIZ020-086- 095-098-099. Winter Storm Warning until 7 PM EST Thursday for MIZ021-022- 025>028-031>034. MARINE...Gale Warning until 7 PM EST Thursday for LHZ345. Gale Warning from 10 PM this evening to 7 PM EST Thursday for LHZ346>349. Gale Warning until 7 PM EST Thursday for LMZ323-341-342- 344>346. Gale Warning from 10 PM this evening to 7 PM EST Thursday for LSZ321-322. && $$ SHORT TERM...MLR LONG TERM...HAD AVIATION...JZ