561 FXUS63 KAPX 101803 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 203 PM EDT Wed Aug 10 2022 .NEAR TERM...(Today through Tonight) Issued at 327 AM EDT Wed Aug 10 2022 High Impact Weather Potential...none. Cold front is progressing across central Superior and western upper MI. There is no precip along the boundary; a broken band of layered clouds slightly trail the front. The more prominent shortwave driving this front will pivot south of James Bay today, largely missing us. But we will see more subtle height falls/mid- level forcing here, especially late this afternoon and this evening. As expected, some fog has formed in southern sections of the forecast area, where winds are lighter. Northern areas have more of a southwest breeze, as the pressure gradient is tightening somewhat ahead of the cold front. Fog is shallow, and will quickly mix out this morning. Cold fropa occurs this morning in eastern upper MI, this afternoon in northern lower. The chance for popping a shower isn't great, but it's not quite zero either. MlCape values will max out at 300-500j/kg. That instability looks to be maximized slightly behind the front, where moisture availability is best (before dry advection strengthens). This is where cloud cover is presently found. Will continue with a slight chance of a shower this afternoon in se Chippewa Co, and in ne lower MI, where any tendency for a lake breeze to fight inland would serve as a potential trigger. Most of the guidance is dry here, but there are occasional RAP runs that generate a shower or two near APN. Another place where a shower could pop is over ne WI. There are more CAMs that allow this convection to cross Lake MI late this afternoon and especially this evening. Most of these target the Ludington area, but holding onto a slight chance for a shower into this evening near MBL seems logical. Will not mention any thunder with any of the above activity. Partial cloud cover will advance southward out of northern MI tonight. Drying northerly breezes should make fog unlikely, except in the most sheltered locales. Max temps today in the 70s to near 80f in eastern upper; in northern lower, from the the upper 70s near Lake MI to the mid/upper 80s near Saginaw Bay. Min temps tonight mostly in the 50s, with some upper 40s in cooler interior locales. && .SHORT TERM...(Thursday through Friday) Issued at 327 AM EDT Wed Aug 10 2022 High Impact Weather Potential: Anomalously dry air mass leading to fire weather concerns... Pattern Synopsis/Forecast: Axis of anomalously dry air extends from southern Quebec across northern Michigan into the central Plains, noted by very dry air/subsidence in water vapor imagery in area of confluence aloft...and surface dewpoints in the 50s. Weak flow across the southern half of the CONUS, with the majority of the activity occurring in this region, though there is some anomalously easterly flow just offshore of the Carolinas helping aid in slight northeasterly generation of convection along surface boundary from this past weekend, which extends along the New England coast down through the OH Valley and into the Central Plains before switching back northward as a warm front...with another weak vort max spinning in the vicinity of AR/TN along this boundary. Meanwhile...across southern Canada...one bowling ball of vorticity is spinning into Hudson Bay as of 3z, dragging a boundary southward from Hudson Bay down into the Dakotas back up into Montana along the thermal gradient, though there is very little in the way of moisture response across the US side of the border, given the anomalous dry air mass in place across the bulk of the Midwest. Another pretty little swirl dropping down into central Manitoba behind this with even cooler air aloft (less than +10C at 850mb), with a surge of warm air ahead of the surface boundary. Further upstream...noting strengthening of the ridge across the western US, with ascent/moisture across the Intermountain West ahead of anomalous upper low still just off the coast of California, and a tropical disturbance off Baja California...with a niblet of energy spinning across B.C. into Alberta. Looking ahead...will anticipate the boundary to our northwest to drop in today, bringing another round of cool/dry Canadian air to the region behind it, as 1025mb surface high pressure drops into the Midwest beneath downstream side of strengthening ridging centered across the High Plains, with closed low spinning toward the Pac NW. Will be on the lookout for some convective activity to try to top the ridge Thursday night into Friday, though exactly where this ends up is somewhat uncertain, and may remain somewhat uncertain for the next day or two, given that guidance tends to have difficulty with convection...but current deterministic guidance seems to suggest the focus may be to our west, as surface high pressure should still be largely overhead here in the Upper Great Lakes. As we go into the end of the week, it does appear that a shortwave ridge axis will try to move overhead here, which could support increased potential for any ridge-riding convection to impact us going into the weekend...so stay tuned. Otherwise, though, anomalously dry air remaining in place with surface high pressure and ridge axis overhead into the end of the week may end up being associated with some fire weather concerns as we will be dry overall for several days in a row this week, despite early-week rainfall. Primary Forecast Concerns: Anomalously dry air/low afternoon RHs through the period...potential convective activity late Friday night?? With surface high pressure overhead as troughing slowly digs off to our southeast...will anticipate not much in the way of activity through Thursday night for our region...and perhaps into the majority of Friday...though things start to get interesting going into Friday night as we get underneath the shortwave ridge axis. Attm...looking at signals for a strengthening instability gradient to our west along the warm air beneath the ridge to approach the region...with LLJ more or less perpendicular to the gradient...along with EMLs beneath the ridge. This is a pretty classic setup for MCS development, particularly noting there should be some assistance from an upper level disturbance overtopping the ridge this weekend. That being said...attm...not a ton of good signals for instability with this feature, with warm advection in the mid-levels potentially helping suppress at least some activity, though at least initially, there may be enough elevated instability to support some thunder. Even so...will have to monitor this closely in the coming days to see how guidance handles this potential feature. Worth noting that if anything does manage to approach our area, it may struggle against the initially anomalously dry air mass in place over the region...so will have to keep that in the back of our minds going forward as well. Speaking of anomalously dry air...pwats potentially below 0.5 inch is quite on the low end of climo for us, so will be on the lookout for lower afternoon RHs through the period, given this air mass. Seasonable highs in the low to mid 70s could be a little on the cool side for producing a sufficient T-Td spread for critical RHs in the mid 20 percent range...but won't be surprised if we end up a little warmer (and perhaps drier) in some areas with downsloping. Best area for this would be the Saginaw Bay region on largely northerly winds...though lake breezes will likely come into play as well, potentially shifting the flow around to some degree. Still...will be something to watch out for going forward. Winds should be light overall both days as well, though could see some slightly increased winds along the Lake Michigan coast as the high approaches Thursday. Additionally, it won't be out of the question for some gusts to be in the 15-20kt (maybe slightly higher?) range Thursday afternoon with some slightly increased winds aloft as the shortwave niblets depart. Other thing to note with this anomalously dry air mass is potential for chilly nights latter half of this week, with dewpoints likely dropping into the 40s. Under clear skies and light winds, would not be surprised to see a few of the typical cold spots try to make a run at 40 degrees or perhaps colder, particularly Thursday night...so will trend overnight lows down for the time being. .LONG TERM...(Friday night through Tuesday) Issued at 327 AM EDT Wed Aug 10 2022 High Impact Weather Potential: Minimal attm...but stay tuned... Pattern Synopsis/Forecast: As mentioned at the end of the short term, will be looking at anomalously dry air mass remaining largely in place over the Great Lakes...though there are some signals for this to begin to depart the area...as the shortwave ridge axis wanes in intensity with some energy topping the ridge this weekend. There are signals for some weak surface responses to this, which should invade the Great Lakes with time. That being said, the pattern overall is supportive of convective activity riding down the ridge like a little kid on a slide, with Michigan potentially in the vicinity of this piece of metaphorical meteorological playground equipment...so will have to keep an eye on this to see exactly how this plays out going forward. It may not be a complete washout, but it should be enough to require some level of weather awareness, particularly if you have outdoor plans as we go into the home-stretch for most families for summer. Beyond this...though guidance varies on the details, there are signals for a return to a troughing-east, ridging-west pattern going into the start of next week as the Pac NW low finally gets absorbed into the flow...and additional energy attempts to sink down from central Canada. This suggests we may remain a little on the cooler side going into the middle of the month. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 153 PM EDT Wed Aug 10 2022 This is the first forecast for KCIU! E Upper MI now joins the TAFs. a weak cold front is moving through E Upper and N Lower Michigan, with Showers triggering along the boundary in E Upper just over the border in Ontario. High pressure is upstream, and nosing into the Upper Great Lakes from the Canadian Prairies. The front is expected to continue fire off isolated showers through the afternoon as it moves from E Upper into NE Lower (near APN) so a shower is possible in the VCTY of KCIU/KPLN/KAPN this afternoon/early evening. As the front moves farther south. The models have the front firing off a shower/thundershower near KMBL late evening (after 02z/Thu) and heading south and east. At this point, TVC doesn't look like it would affected. The high pressure builds into the region and all the TAF sites should be quiet going on after 06z/Thu and on toward 18z/Thu. && .MARINE... Issued at 327 AM EDT Wed Aug 10 2022 A cold front will cross the region today. Southwest winds ahead of the front will veer nw behind it late in the day, and become northerly tonight. Waves will get choppier, but for now winds/waves look to stay below advisory levels. Breezy north winds persist into Thursday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ NEAR TERM...JZ SHORT TERM...FEF LONG TERM...FEF AVIATION...JSL MARINE...JZ