607 FXUS63 KAPX 201749 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1249 PM EST Mon Jan 20 2020 .UPDATE... Issued at 920 AM EST Mon Jan 20 2020 Despite a very shallow convective layer (sub 3kft on local 12z sounding) and complete dearth of synoptic moisture contribution, inversion top temperatures right in the prime dendritic growth region is enticing quite a bit of shallow lake response...as evident by widespread clouds and flurries in the favored snow belt regions. Expect a slow downward trend in these clouds and flurries heading through this afternoon as diurnal mixing increases. Otherwise, near normal high temperatures expected with afternoon readings in the 20s. && .NEAR TERM...(Today through Tonight) Issued at 321 AM EST Mon Jan 20 2020 ...Relatively quiet... High Impact Weather Potential: Minimal. Some light lake effect snow nw lower and eastern upper MI. Chilly high pressure sprawls across the central and northern plains. The incoming airmass remains very dry, especially at low levels. N to nnw low-level flow continues to produce lake-induced clouds and flurries in nw lower MI, where the effective Superior/Michigan fetch is longest. The shorter fetch into ne lower MI isn't producing any clouds at all over land, though a streamer does begin offshore of Thunder Bay. The above is resulting in some massive temperature spreads early this morning, with a number of places east of I-75 in single digits below zero, while the nw lower MI coastline is in the low-mid 20s. The high will move steadily se, toward the mid MS Valley. The 850mb thermal trof ahead of the high is overhead, with -14/-15C air at 850mb. We will gradually warm on nw-erly flow thru the forecast, gaining about 2C today and another 3-4C tonight. This is with winds slowly backing, to nw today and wnw tonight. Light lake effect snow showers will migrate gradually eastward into parts of n central lower MI, and will also push back into parts of eastern upper MI (noting that there is already a stray streamer over CIU). This should all be on the light side; perhaps some land-breeze- forced convergence can squeeze out a half-inch of snow this morning near MBL. There is also some mid-level moisture grazing that area this morning, associated with a vigorous but moisture- starved shortwave digging to our west. Lake effect snow will gradually diminish thru today and this evening, thanks for warming 850mb temps and lowering inversion heights. There may be some potential for that transition to include some freezing drizzle; we don't normally see that historically, but we've managed it a few times this winter. Our near-surface temps look to be a little too cold for that. For now will not explicitly include in the forecast, though the best chance for it will be this afternoon/evening as we get just a little warmer. Cloud cover today will mostly reflect current trends, with considerably more clouds west of I-75 than east, in both peninsulas. Some possibility for decreasing clouds late today near TVC/MBL, as better stratocu lifts toward CVX/GLR. Cloud cover will decrease somewhat tonight, with partly cloudy to mostly clear skies across the area. Max temps today mainly in the mid 20s. Min temps low-mid teens, but some locally colder readings can certainly be expected. && .SHORT TERM...(Tuesday through Wednesday) Issued at 439 AM EST Mon Jan 20 2020 ...Precipitation Chances Start to Return Wednesday... High Impact Weather Potential...Light snow accumulation for eastern Upper Michigan by late Wednesday Pattern Synopsis/Forecast...Quiet weather is expected across eastern Upper and northern Lower MI for Tuesday as surface high pressure and upper-level ridging slide across the Great Lakes. Temperatures will be about where they should be for mid-January, with readings topping out in the 20s. Forecast area will begin to be impacted by a relatively weak and poorly phased northern/southern stream short wave by Wednesday. While the best dynamics with this will be north/south of the region, with the stronger part of the northern/southern stream waves respectively, the disturbances will push a weak surface boundary toward the area. Decent moisture return & isentropic upglide ahead of the boundary will result in the return of a precipitation risk by later Wednesday over eastern Upper and a portion of northern Lower (mainly northwest 1/3). Most of the precipitation should fall in the form of snow, although with most locations expected to top out in the mid 30s for highs, some change over to rain is possible. Forecast soundings also suggest a localized risk of freezing drizzle as ice in the clouds may be lacking at times. However, confidence in this occurring, especially with the limited areal extent anticipated, precludes mention at this time. The snow that does fall may result in a light accumulation across eastern Upper. .LONG TERM...(Wednesday night through Sunday) Issued at 439 AM EST Mon Jan 20 2020 High Impact Weather Potential...Limited risk at this time, but potential late week system will need to be monitored. An extended period of precipitation risk will linger into the weekend. This will initially be with the nearly stalled frontal boundary that will first impact the region on Wednesday. Main precipitation risk with the boundary in the area remains snow, but rain can't be ruled out given the relatively mild thermal profiles. A cutoff upper-level low is forecast to develop over the central Plains by Thursday or Thursday night. This disturbance, and associated surface low, is forecast to drift slowly east or northeast with time. This could result in an enhanced risk of precipitation across the forecast area by Friday into Saturday. However, model agreement is the explicit timing/track of this system is not very good. Some solutions have the precipitation with this system staying entirely south of the region. We'll need to watch trends with this system closely the next few days. In any event, it looks like temperatures will be several degrees above normal through the end of the period, with daytime highs climbing near or above freezing. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1248 PM EST Mon Jan 20 2020 MVFR to low end VFR conditions this afternoon as lake clouds and attendant flurries overspread the taf locations. Slow improvement expected tonight as over-water instability wanes. Mostly clear skies with just some passing high clouds Tuesday morning. && .MARINE... Issued at 321 AM EST Mon Jan 20 2020 Northerly winds will back nw today, and toward the west tonight. Small craft advisory conditions are possible today near Presque Isle Lt on Lk Huron. Otherwise, we should be below criteria into early Tuesday. Winds/waves may increase enough to reach advisory criteria beginning Tue afternoon and carrying into at least Wednesday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...SMALL CRAFT ADVISORY until 8 PM EST this evening for LHZ347-348. LM...NONE. LS...NONE. && $$ UPDATE...MB NEAR TERM...JZ SHORT TERM...PB LONG TERM...PB AVIATION...MB MARINE...JZ