Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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541 FXUS63 KAPX 290526 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 126 AM EDT Sat Jun 29 2024 .KEY MESSAGES... - Marginally severe storm possible Saturday. Primary hazard is gusty winds. - Drying out Saturday night into Sunday; clear and cool Sunday night. - Various chances of showers and storms at times Monday night and into later next week. && .UPDATE... Issued at 939 PM EDT Fri Jun 28 2024 Upstream low pressure center has reached the Upper Mississippi Valley late this evening. Associated warm front has pushed into our far SW CWA. Initial area of showers developing along and ahead of that warm front continues to impact much of our CWA. A look upstream shows an area of showers and thunderstorms organizing over the SE half of Wisconsin within the nose of an instability axis and an area of deeper low level moisture. This instability axis is expected to lean into our CWA overnight into Saturday morning...providing better chances of showers and embedded thunderstorms. Even so...elevated nature of this convection with limited instability will preclude chances of strong/severe storms overnight. Temps will hold nearly steady in the upper 50s and lower 60s. && .SHORT TERM /THROUGH SUNDAY/... Issued at 343 PM EDT Fri Jun 28 2024 PATTERN SYNOPSIS/FORECAST: Surface pressure continue to fall over the Upper Midwest...with warm frontal trough taking on a more defined look in the last few hours...stretching from southern MN to SW WI. Surface dewpoints finally starting to creep up early this afternoon amid continued warm advection and overspreading of some light rain/sprinkles sneaking out of the mid-cloud deck overhead. Even starting to see some lower clouds slip in along the Lake MI coast near MBL and points south. Winds not terribly gusty today, except where clouds break just enough to allow for some better mixing, particularly upstream; otherwise, stronger winds aloft struggling to mix to the surface...though a few spots are managing to gust up toward 20-25kts, so will hold onto the small craft advisories for now. Warm front to continue to lift northward into the region tonight...with increasingly humid conditions on tap for the overnight into Saturday morning. Warm and wet overnight...with embedded thunder at times; even potential for a round of storms along/ahead of an initial front expected to slip through during the morning hours. Some clearing possible behind this...with a second PV maxima dragging a secondary cold front in during the afternoon...which certainly has some potential for activity as it could coincide with peak heating amid a relatively moist environment. Primary Forecast Concerns: Isolated/conditional severe storms possible Saturday... Not entirely out of the question that the morning round along/ahead of the initial cold front could have some isolated severe activity with it, noting guidance soundings still suggest 500-1000 j/kg of MUCAPE are possible above 850mb warm front...though this idea is conditional on having enough forcing to tap into this, which is slightly unclear. Assuming this idea does come to fruition...think hail could be a threat, given signals for elevated nature of the convection...though the downside is that the freezing levels may be quite high (above 12kft)...unless any updrafts get better organized. Wind may not be entirely off the table in this case, though, as it could promote downbursts...but strong inversion could dampen out any downward momentum transfer...such that we may not know if any wind is making it to the ground until we get reports. Front may be somewhat slow-moving Saturday, which could allow for better destabilization across our SE, esp along and south/east of a line from APN to MBL. Noting deep-layer shear should be on the increase with time...certainly a possibility that any storms that develop could become better organized during the afternoon. Not even entirely off the table that the secondary trough/cold front could set off some additional activity further west than currently anticipated. Think the primary threat with these would be gusty winds noting a lot of dry air aloft; hail may not be quite as much of a threat with freezing levels up around 12kft...unless we manage to get anything much better organized. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 343 PM EDT Fri Jun 28 2024 Pattern Synopsis / Forecast: Following the passage of a trough axis (which will help fire storms Saturday evening / early overnight), a flattening 500mb wave and associated surface low pressure will continue trekking eastward through Ontario Saturday night, as stout area of surface high pressure moves overhead Sunday night into Monday. Troughing over central Canada will then induce an area of zonal flow across the region, bringing about a favorable regime for embedded shortwaves to move into the region on the backside of the surface high. Moisture return and the presence of these waves will culminate in a period of returning unsettled weather late Monday night through Wednesday. Primary Forecast Concerns: Saturday - Sunday: Pesky lingering moisture and a trough axis pivoting the parent shortwave will be traversing the region Saturday evening into the overnight hours. This may lead to prolonging of shower and thunder activity Saturday evening into early Saturday night. Expectation is that the majority of this activity wanes in coverage and intensity as we lose diurnally driven instability, but still could see a locally stronger to perhaps marginally severe storm... primary hazard being gusty winds. As such, SPC maintains a Day 2 Marginal Risk for severe storms (Level 1/5) across This will be relatively short-lived as a subsidence inversion builds overhead later Saturday night, suppressing any lingering shower activity as the aforementioned surface high pressure moves in. Clouds are set to erode from west to east through the morning Sunday as what is left of the low level moisture is scoured from the profile, resulting in a pleasant day with temperatures in the 60s and 70s, and lows ranging from near 40 inland to the lower 50s by the big lakes Sunday night. Midweek: The transient nature of the surface high will be rather short lived, with return flow building through the evening hours Monday, and thus, the initial return of cloud cover as moisture is quickly drawn back into the Great Lakes. Convectively charged wave with origins in the central Plains and western Corn Belt will try to make its way into the upper Great Lakes via increasing low level jet influences. Expectation is that a decaying batch and/or line of showers and thunder will move into the region Monday night, and given that the core of the deeper moisture remains to our west in Minnesota and western Wisconsin, would be less than surprised to see the more robust convection hold tour southwest, while the leftovers of this potential activity struggles its way into the APX footprint. Aforementioned area of deeper moisture will eventually settle into our wheelhouse later Tuesday into Wednesday as the core of the amplified 850mb flow is forced overhead by an intruding trough over central Canada. Given support aloft via an approaching cold frontal boundary, additional shower and thunder development may manifest Tuesday evening into Wednesday as 500mb height impulses build into the region. As stated by previous forecaster, still a little too early to be throwing out exact QPF for this period, but could be a sneaky setup for multiple rounds of convection as 850mb winds run parallel to the front, basically slowing its south and eastward advancement to a crawl... could be one to watch if one has holiday week plans. As is tradition, still plenty of finer details to iron out between now and then. Looking toward the holiday, moisture will be slow to exit the region. Couple this with lingering troughing, it will be possible for some additional nuisance showers to leak into the Independence Day holiday on the 4th at this juncture. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 126 AM EDT Sat Jun 29 2024 Low pressure will cross Lk Superior and continue ne thru Saturday. This will drag a cold front across the area this afternoon and evening. Periodic showers continue overnight, with precip coverage waning for a time by mid/late morning. Additional SHRA and perhaps TSRA swing in from the w and nw, between 21Z and 04Z. Cigs will lower to IFR or low-end MVFR overnight, then improve after sunrise. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until 2 AM EDT early this morning for LHZ346>349. Small Craft Advisory until 8 AM EDT this morning for LMZ323- 341-342-344>346. && $$ UPDATE...MLR SHORT TERM...FEF LONG TERM...HAD AVIATION...JZ