488 FXUS63 KAPX 220356 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1156 PM EDT Thu Jul 21 2022 .UPDATE... Issued at 1022 PM EDT Thu Jul 21 2022 So far the forecast is going according to plan. Winds have died off over the Upper Great Lakes Region has high pressure noses in for a bit. A few clouds are drifting down out of NW Ontario into Lake Superior, from a shortwave trough at 500 mb. This looks to be producing just mid-level clouds over the lake, so not expecting much if anything with these overnight. Otherwise, things look quiet overnight. && .NEAR TERM...(Through Tonight) Issued at 323 PM EDT Thu Jul 21 2022 High Impact Weather Potential: Minimal. Pattern Synopsis/Forecast: 17z surface analysis shows a 986mb occluded low off the southern end of James Bay along the Ontario/ Quebec border...cold front extends southwest from this low across central Upper/northwest Wisconsin/Iowa. Brisk westerly boundary layer flow across the upper Lakes this afternoon. Good bit of diurnal Cu across the upper Great Lakes this afternoon...with more vigorous convection across northwest Ontario with a couple bands of thunderstorms associated with a vorticity center evident in water vapor imagery. A little patch of St/fog hanging on along the southeast shore of Lake Superior. Northwest Ontario vorticity center expected to pass north of Lake Superior this evening...with a second disturbance coming in quickly on its heels out of Saskatchewan this afternoon and into the upper Lakes by Friday morning. A frontal wave is expected to develop along the secondary cold front over Wisconsin and slide across southern Lower Michigan tonight. Primary Forecast Concerns: Forecast concerns appear to be pretty minimal...diurnal clouds will fade with loss of heating but some residual Ac at times. Winds will also drop off later this evening as pressure gradient relaxes...and with dew points having mixed out a bit this afternoon should have more room to cool off overnight...55-60 across eastern Upper and upper 50s-lower 60s across northern Lower. && .SHORT TERM...(Friday through Sunday) Issued at 323 PM EDT Thu Jul 21 2022 High Impact Weather Potential: Storm and heavy rain potential this weekend...elevated fire danger Friday... Pattern Synopsis/Forecast: Some additional upper level energy diving into the general area of troughing over the Great Lakes this morning...left behind by yesterday's potent little shortwave aloft...which is currently spinning northnortheastward toward James Bay. A little bit of energy driving some mid-high clouds across southern WI as of 14z...with additional energy making its way toward the Upper Midwest/Great Lakes from the central Canadian Prairies. Northwest flow through the column in the wake of this trough resulting in a cooler and drier airmass advecting into the region today...particularly behind a second cold front currently extending from a low near western Hudson Bay down into the central Plains. This surface boundary quickly turns north along the high plains as a warm front, on the periphery of ridging that continues to persist across the western US. For the time being, bulk of the moisture is held across the eastern seaboard and southern US, south of the cold front associated with yesterday's convection (and driving additional convection across the TN valley into northern TX this morning). Further upstream...note continued anomalous troughing across the Bering Straits...with some general area of lowered heights aloft off the West Coast...and a vort max within this area spinning toward the Pacific Northwest attm. Looking ahead...anticipate bulk of the northern stream energy will continue to sideswipe us to the north through the next 24 hours or so...with some additional energy attempting to scrape by Friday afternoon...leading to some weak surface pressure falls across the region...and ultimately, some semblance of a boundary/baroclinic zone over the region. As energy currently off the PacNW coast heads inland...and some additional northern stream energy swings southward across the central Canadian Prairies...will look for the flow to become a bit more zonal for a time for the end of the work week into the start of the weekend, with strengthening thermal gradient and subsequent strengthening of upper level jet across the northern half of the CONUS. Bermuda high off the southeast US in combination with the approaching lowered heights and surface pressures will result in increased low-level return flow across the central CONUS/MS Valley going into Saturday and Saturday night. Strengthening west to southwesterly flow should also provide transport of upstream capping/EMLs into this same vicinity. Some uncertainty attm in exact position/depth of troughing across southern Canada as it approaches Saturday night...and drives a cold front across the region through Sunday. Will certainly be keeping an eye on this setup for the weekend...as convection will become a concern across the Midwest, noting Day 3 marginal risk has been hoisted for all of Michigan...and even an enhanced risk across central/western WI for Saturday into Saturday night...with Day 3 excessive rainfall outlook for this region from WPC. Primary Forecast Concerns: Heavy rain and severe storm potential through the period...particularly Saturday into Sunday...non- thunderstorm gusty wind potential as well... Friday may not be entirely quiet...noting a niblet of energy swinging through during the day, which may be just enough to set off a few diurnal showers here and there (non-zero thunder potential), particularly across the eastern UP as it drops some kind of weak boundary into the region. This appears to also briefly increase winds across the area, leading to a breezy/gusty afternoon to wrap up the work week. Wouldn't be surprised to get some gusts into the 30+kt range across interior northern lower as a bit of a wind max moves overhead and we get some good deep mixing. (Could we be looking at a sneaky non-thunderstorm wind event?? We'll see...) Antecedent dry weather may preclude some precip development, though...particularly across northern Lower, where it looks driest attm...and also lead to fire danger concerns (particularly in combo with temps and winds), noting Great Lakes Fire and Fuels page has very high fire danger across a good portion of northern Lower attm...particularly along and south of M-72. This should only expand northward with time into Friday as drier conditions take hold. Going into Friday night, mid-level flow looks to become relatively parallel to this boundary over the region as nocturnal LLJ begins to set up to our west. Setup favors some kind of convective development along strengthening/approaching warm front across the Midwest late Friday night into Saturday, as reflected in some guidance...though instability gradient may be a little more nebulous (perhaps due to the convective development), which could make the forecast a little tricky on the details. Do certainly see signals of increasing deep moisture, along with theta-e advection, and steepening lapse rates aloft as upstream EMLs beneath the ridge become advected eastward...so will definitely have to keep an eye on this. Suspect that with flow parallel to lingering boundary...whatever convection develops Friday night/early Saturday may be a little more progressive with potential for cold pools to become congealed. Exactly where this ends up evolving is a little uncertain...though attm, bulk of the signals would like to keep it primarily to our south. So stay tuned. Going into Saturday...will be watching whatever convection from Friday night continue eastward through the morning, and its impacts (or lack thereof) will play a role in the setup for the rest of the day into Saturday night. Flow should become veered from the surface into the mid-levels during the daytime hours as upstream low strengthens and approaches. Meanwhile...instability should be on the increase through the day into Saturday night thanks to that increasing southwesterly flow...with increasingly steep mid-levels as EMLs and warmer temperatures advect in in advance of shortwave, with the warm front moving in late in the day. Warmth of the air mass may be able to overcome capping with enough diurnal heating...though this would depend on convective cloud debris from the overnight convection, how moist we get in the low-levels...and just how warm we end up getting aloft. So we may end up having to keep an eye out for pop-ups during the day, which could get interesting, noting some signals for veering flow in the low levels, though low-level shear doesn't currently appear too strong during the afternoon...likely not increasing until overnight, as the LLJ picks up (as do the surface winds, with the approach of that system). Deep-layer shear would be the greater concern...and that should be reasonable. Anticipated upstream convection Saturday afternoon will increase threat for storms and heavy rain as it heads into our area later in the day...and do note signals appear favorable attm for some kind of backbuilding/training convection along the warm front Saturday night. Anomalously high pwats do lend to further concerns for heavy rain...so will definitely have to keep an eye on this. Progressive nature of the system may keep things from sticking around too long and potentially minimize said heavy rain threat to some degree, as the cold front appears to slide through starting late Saturday night into the first part of Sunday. Ultimately, I expect that details will change over the next 24-48 hrs...but the overall concern remains present for thunderstorms (potentially severe) and heavy rain across our region Saturday through Saturday night. Will definitely be a weekend to keep a close eye on the weather, particularly if you have outdoor plans that will have you out in northern Michigan's beautiful Great Outdoors... especially if you plan to camp Saturday night. Otherwise...Sunday could be another gusty day early in the day as the cold front moves through...noting some anomalously strong winds aloft...though bulk of these winds attm appear to be just to our south. Even so...will keep an eye on things, as it could get a bit blustery for a time before things eventually quiet down. May have to keep an eye out for some lingering showers/storms near Saginaw Bay depending on how warm it gets...and how quickly the front moves out in the afternoon Sunday...though it looks a bit dry attm for much in the way of convection to develop. .LONG TERM...(Sunday night through Thursday) Issued at 323 PM EDT Thu Jul 21 2022 High Impact Weather Potential: Minimal for now. Temperatures look to remain pretty consistent next week as we get sandwiched between airmasses in the upper Great Lakes. High temperatures likely hold in the mid 70s to low 80s, with low humidity to start before dewpoints slowly creep back into the 60s around midweek. A longwave over Quebec will continue to meander slowly toward the Maritime Provinces Sunday night, forcing the shortwave over the Great Lakes eastward and favoring a drying trend into Monday as high pressure sneaks in from the west. Jet stream flow will turn more zonal and quite quick at that, with up to 100kt flow placed directly over Michigan. Convergence aloft will likely limit any CU field development on Monday...with any low level moisture eventually mixing out through the morning, yielding a good possibility of at least a sunny afternoon. High pressure remains in place for Tuesday, but as surface flow turns ever so slightly southerly ahead of a digging trough from the MB/ON vicinity, surface moisture should slowly begin to advect back into northern Michigan, perhaps accompanied by an isolated shower or rumble of thunder overnight into Wednesday. The risk for showers and perhaps some rumbles would likely carry into Wednesday and even Thursday as the pattern becomes a bit stagnant owing to an amplifying ridge across the western U.S. and Canada. It should be noted that there remains some uncertainty regarding how far south the trough will dig, which would have significant impacts as to how much moisture can be advected into the area, but model guidance has shown signs of backing off on this ever so slightly. In the event that a SW to NE jet streak from Missouri to Quebec can develop like models suggest, this may lead to a more widespread area of precipitation across portions of the Great Lakes given better divergence aloft. Unfortunately, given the position of this jet streak, the better divergence aloft will likely favor areas of eastern Ontario to the Ohio Valley, with the cards looking to be tilted in the favor of the southern Great Lakes. This would unfortunately leave us with "lottery showers" in northern lower and eastern upper Michigan for Wednesday and Thursday, because one might have to have a bit of luck on their side to get some jackpot rainfall. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1146 PM EDT Thu Jul 21 2022 Tonight, and leading into Friday morning should remain quiet, with light winds. Friday, however, The winds will pick up again and become gusty by the later morning. A shortwave trough will drop into the Upper Great Lakes, and begin to kick off some showers, and possibly thunderstorms, which would be an issue for PLN and APN late in the afternoon/early evening. However, it looks like that all of the TAF sites should remain VFR for CIGs and VSBYs through the period. && .MARINE... Issued at 323 PM EDT Thu Jul 21 2022 Small Craft Advisories up for the Lake Superior and most of the Lake Huron nearshore zones will be allowed to come down at 00z as winds drop off for a time tonight. But another round of headlines appears to be in the offing for Friday especially on Lake Michigan as winds come around from the southwest. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JSL NEAR TERM...JPB SHORT TERM...FEF LONG TERM...HAD AVIATION...JSL MARINE...JPB