065 FXUS63 KAPX 190836 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 436 AM EDT Sat Mar 19 2022 .NEAR TERM...(Today through Tonight) Issued at 433 AM EDT Sat Mar 19 2022 High Impact Weather Potential: Minimal. Pattern Synopsis/Forecast: Split flow pattern across North America early this morning with CONUS dominated by southern branch and the northern branch confined to Canada. Remnants of an upper low are lifting northeast across the Ohio Valley in several pieces...water vapor imagery shows one piece over Ohio/Lake Erie...a second over Indiana. System has pulled decent deep layer moisture into the Great Lakes with precipitable water values above 0.70 inch across Lower Michigan. Surface analysis at 03z places a 1001mb low over eastern Illinois with a warm front extending east across Indiana/ Ohio/northwest Pennsylvania. 1024mb high centered over northern Quebec ridges back to the southwest into Minnesota. Dynamic and isentropic ascent plus moisture advection resulting in widespread precipitation across northern Michigan...currently falling as mostly rain with some snow across central Upper. Somewhat surprising to still see liquid precip for the most part across eastern Upper given what appears to be a minimal amount of melting energy aloft. There is a break in the precipitation coverage across southern Lower where things are a bit more showery/convective in nature. 00z APX sounding had a warm layer about 60mb deep with a maximum temperature just above 1C...but the boundary layer has been warm enough to keep precipitation rain after a late afternoon burst of graupel/sleet. Illinois surface low expected to track across southeast Lower Michigan and southwest Ontario today where strongest pressure fall center currently resides (2-3mb/3h). Cyclonic gradient lingers across Michigan into this evening...with high pressure building into the upper Mississippi Valley tonight. Thus boundary layer flow will back from northeast this morning to north and northwest this afternoon. Primary Forecast Concerns: Precipitation evolution...which looks like it's going to continue for the majority of the day...perhaps more periodic at times south of M-72 and think coverage will tend to shrink toward evening as isentropic ascent winds down. Precipitation type will probably end up being mostly liquid today with a mix/ change to snow at times. As the system continues to pull away from Michigan drier air will advect into the area...which will bring any lingering precip chances to an end this evening followed by decreasing cloud cover. && .SHORT TERM...(Sunday through Monday) Issued at 433 AM EDT Sat Mar 19 2022 Pattern Synopsis/Forecast: Last 24-48 hours has seen the troughing across the center of the country become more negatively tilted as it progresses eastward...opening up a little bit as it reaches the Great Lakes attm. Vort maxes within the larger trough exist to our south across the Ohio Valley...closer to the surface boundary itself...with 1001mb occluded surface low over central Illinois at 0z becoming more or less vertically stacked; triple point is located over western Kentucky, with cold front extending southward along the border between Mississippi and Alabama, where yet another surface low and an E-W warm front is noted nearly along the coast at 0z, separating moist from very moist air coming in off the gulf...though this doesn't stop decent slug of moisture from being advected north into the Great Lakes on generally southerly flow ahead of the system...as evidenced by pwats of 0.66" at APX (0z/19 sounding), above normal for this time of year...and isentropic ascent results in precipitation in the area attm. E-W oriented baroclinic zone across the Ohio Valley/New England denoted actually by a cold front at 0z extending from central Illinois into Maine; do see a second surface low analyzed over western Lake Erie attm, near the cusp of the dry slot on WV imagery poking into the Ohio Valley, and beneath better height falls aloft. Some convection is also firing across Georgia along the edge of this dry slot aloft. Elongated area of surface high pressure centered over Quebec, north of this boundary, oozes back across southern Ontario, allowing for easterly flow over northern Michigan and keeping things a touch cooler in the lower levels/at the surface here in northern Michigan than further downstate, as evidenced by nearly isothermal layer around the 0C line through about 800mb on the 0z/19 APX sounding; downstate at DTX, thermal profile is much warmer, with a strong inversion up to 10C just above the surface through about 875mb, and much warmer surface temps as well...though surface temps here in the Great Lakes are at or above freezing as of 3z. Teeny bit of elevated instability across southern Michigan is helping to promote some lightning strikes to our south within the precipitation shield. Upstream...northern stream shortwave energy approaches the Great Lakes from the west across the international border, denoted by a nice little swirly in WV imagery over the northern Plains...with a triple point located over northern North Dakota...with occluded front extending northward into Manitoba, and cold front extending back to the west along the baroclinic zone aloft from Montana into southern Alberta. There is a nice swath of dry air on wv imagery across Minnesota into the central Plains between our system and the upstream one, outlining the back edge of our comma head...associated with a strand of vorticity along the backside of our closed low. Meanwhile...further upstream...ridging still tries to hold on across the west coast, becoming more negatively tilted as upstream cold closed low digs into the Gulf of Alaska...with another niblet of energy digging eastward a bit further southwest of that, south of the Aleutians. Going forward...will look for troughing overall (northern and southern stream) to depart the region through the weekend...with ridging ahead of a digging system in the western US bumping up against a bit of northern stream energy trekking across Ontario Sunday night into Monday. That digging system in the western US is part of the trough energy currently in the Gulf of Alaska...and will look for a very amplified pattern across the CONUS with this system for early next week...with troughing across the center of the country...sharp ridging developing ahead of it...and another strong ridge behind it along the West Coast of North America, sharpening up as additional energy in the Gulf of Alaska sharpens up as well. Exact evolution of troughing across the central US is still uncertain attm...which indicates continued uncertainty for the forecast for the latter half of the short term going into early next week...but baroclinic zone currently appears to hang out over the Great Lakes going into Monday, suggesting we could see some active weather for the start of the workweek. Primary Forecast Concerns: Winds and precip concerns Sunday night into Monday... Pressure gradient should be relatively loose through the day Sunday...as high pressure briefly settles in between departing surface low...and next system on the horizon. Pressure gradient will tighten up to our west between surface high and that next system to our west/southwest...but depending on exactly how the pattern evolves (i.e., do we stay more under the influence of high pressure on the cool side of the baroclinic zone?), may take a bit for the tighter pressure gradient to move into our area from the southwest. Subsidence should be the prevailing story for the daylight hours Sunday...as left entrance region of the upper level jet passes overhead...and surface high pressure hangs around. Will look for any low-level moisture hanging around in the morning to start to mix out during the day as that subsidence moves over head...so save for perhaps a few sprinkles here and there, it should be a pretty decent and benign day overall...with warmest temps near Saginaw Bay, where some downsloping may occur, given northwest flow. Things become a little more interesting going into Sunday night and Monday...as high pressure to our north and a weak niblet of vorticity slide by...while system to our southwest develops ahead of that sharp trough digging into the western US...and return flow kicks up behind surface high sliding by to our south and east. This should act to tighten up a thermal gradient across Michigan (WNW/NW - ESE/SE oriented)...and will look for the upper level jet to intensify with time over this area as well. This should promote more favorable upper level forcing over the Great Lakes going forward into the start of the workweek...perhaps particularly over northern Michigan...and depending on how exactly the pattern evolves going into the end of the short term, potential for more substantial forcing, as we'll be watching for the jet to strengthen to our north and to our south ahead of the approaching trough. Meanwhile...back in Sunday night-Monday land...warm advection ahead of the trough to our west will promote isentropic ascent over the thermal gradient that will lie somewhere across Michigan late Sunday night into Monday morning...leading to a tight/narrow E-W(ish) band of deepening moisture expanding across the center of the state. Potential is there again for anomalous pwats with this band (perhaps greater than a half inch again, which would be on the high end of climo for this time year)...so will have to keep an eye on this, as it would suggest decent QPF, particularly noting that forcing will be decent with this as well...as the tightening thermal gradient in the area will promote frontogenesis, further enhancing forcing (beyond isentropic ascent and some dynamic forcing from the jet). Fgen signals currently look to hold off till Monday morning and perhaps into Monday afternoon...and exact position of this (and of course the baroclinic zone/surface boundary itself) will determine which areas see precipitation with this system. Would not be out of the question for a narrow generally E-W swath of half inch or greater QPF somewhere in Lower Michigan, mainly during the daylight hours Monday and tapering off through the evening/overnight, though how well this materializes over our CWA is yet to be seen. If surface high to our north is a little stronger and further south...this would shift the setup and heaviest precip potential southward (perhaps entirely, assuming a sharp cutoff in totals on the northern edge of the band)...which is a possibility...though we are certainly not out of the woods yet. Definitely worth keeping an eye on in the coming days, particularly considering the QPF we're experiencing attm. Current guidance places heaviest QPF across the M- 55 corridor during the daytime hours Monday, which makes sense...though will expect this to shift around between now and Monday. Other concern with this forecast will be p-type...as there are some suggestions in guidance that we could be warm enough aloft to get some flip-flopping back and forth between rain/snow at times, or perhaps all rain if it's warm enough. Location of the surface boundary will play a strong role in how warm it gets over the area (in addition to where the heaviest precipitation ends up occurring). Additionally...there is some suggestion that the dry environment in the low levels to start out Monday morning could promote evaporative cooling as we saturate from the top down...leading to precipitating starting out as or transitioning to snow in some areas. Another challenging p-type event to say the least. Any snow that does fall will more of the wet, dense snow with this event, given how warm the thermal profile is. Depending on how long the precip lingers into Monday night...may have to watch out for it to turn back a little more wintry-mixy. Fun. && .LONG TERM...(Monday night through Friday) Issued at 433 AM EDT Sat Mar 19 2022 High Impact Weather Potential: Watching potential for strong winds and active weather for mid week... Pattern Synopsis/Forecast: Amplified pattern across the CONUS will continue into the middle of next week...with troughing ultimately appearing to meander eastward through the end of the week as ridging eventually begins to spread across the western and central US. Continued uncertainty exists with this pattern, given some disagreement on details of how the trough evolves as it treks eastward...though there are signals for longwave troughing to take on an overall positive tilt with an axis across the Great Lakes going into the middle of next week...and a surface system to approach the Great Lakes during that timeframe as well. Attm...signals suggest a pretty stiff pressure gradient with this surface system for mid-week and beyond, so have tweaked winds to some degree to match up with neighboring offices. Worth noting that straight-up blend/consensus guidance gave me some gusts greater than 30kts for Wednesday across the SW CWA, so this will be something to keep an eye on, and do see signals attm for a decently strong LLJ just off the surface, which could mix down to some degree despite warm advection. Something to keep an eye on. Current signals also suggest this could end up a little cooler than what we're expecting behind our current system, depending on just how this evolves, though normals for this time of year are highs in the upper 30s to low 40s in most locations. Will therefore have to watch this for potential p-type issues, though that is still quite a ways out...so will be monitoring it in the coming shifts. Potential for some additional cold air intrusion exists for next weekend behind this system, though that will depend on how zonal the flow remains behind the departing trough. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1142 PM EDT Fri Mar 18 2022 Low pressure centered across southern Indiana tonight will continue to trek northeastward tonight...reaching far southern lower MI by 12z Saturday. Waves of widespread precipitation will continue tonight through much of Saturday. Light snow may mix in at times tonight at PLN...with the rain/snow mix impacting much of northern lower Michigan Saturday afternoon into Saturday evening as colder air begins to arrive in the wake of the departing low center. Primarily IFR conditions are expected at all of northern MI's terminals thru Saturday with some periods of LIFR cigs possible. Surface winds will remain from the northeast AOB 10 kts through Saturday morning...backing more northwest Saturday afternoon and becoming occasionally gusty. && .MARINE... Issued at 433 AM EDT Sat Mar 19 2022 Small craft conditions likely to continue within the northwest Lower Lake Michigan nearshore zones through much of the day especially south of Grand Traverse Light. Meanwhile winds will diminish later this morning on the Lake Huron side...but may pick up again tonight in Presque Isle Light to Thunder Bay corridor aided by northwesterly coastal convergence. May re-jigger current SC.Y in place for the Straits to Presque Isle Light zone...re-issuing for tonight into Sunday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...SMALL CRAFT ADVISORY until 6 AM EDT Sunday for LHZ347-348. SMALL CRAFT ADVISORY until noon EDT today for LHZ349. LM...SMALL CRAFT ADVISORY until 5 PM EDT this afternoon for LMZ344>346. LS...NONE. && $$ NEAR TERM...JPB SHORT TERM...FEF LONG TERM...FEF AVIATION...MJG MARINE...JPB