Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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094 FXUS63 KAPX 131050 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 650 AM EDT Mon May 13 2024 .KEY MESSAGES... - Shower/storm chances return in southern areas today and tonight. - Patchy frost possible Tue night and Wed night. && .SHORT TERM /THROUGH TONIGHT/... Issued at 335 AM EDT Mon May 13 2024 Synopsis/pattern: Low pressure up toward James and Hudson Bays is pushing a cold front into eastern upper and northern Lake MI. Precip is well out ahead of the front, with drier mid-level air gradually overspreading northern MI. The front will slow its progress across lower MI today, in part thanks to a surface low over MO. A shortwave now in northern MN will also interact with the frontal zone later today. Forecast: Shower coverage/intensity continues to gradually wane, with precip generally near and south of an MBL-Harrisville line. Partial clearing has occurred north of this. Precip is expected to (temporarily) exit northern MI early this morning. Increasing diurnal heating, along with continued coolish temps aloft in low-amplitude troffing over the Great Lakes, will allow instability to quickly regenerate near and ahead of the front. As soon as late morning, a few hundred J/kg of MlCape will redevelop, with forcing initially available in the form of the front. Showers will start to get going again by late morning, mainly east of US-131 and south of M-72. Coverage will remain somewhat limited until deeper into the afternoon, when instability downstate is higher, and when backing sub-850mb winds will advect this unstable air to and across the frontal surface. Even with the front moving downstate this afternoon, showers become likely, with a few thunderstorms, south of an HTL-OSC line. Coverage only slowly dwindles this evening, but does continue a downward trend into and thru tonight as the front continues toward far southern lower MI. Max temps in the 60s to mid 70s. Boosted max temps over guidance in northern sections, which will be the sunniest today. Min temps tonight with have some mid 30s in the cold spots (especially the eastern UP, where the growing season has not yet begun), but range up to the mid 40s in the se. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Issued at 335 AM EDT Mon May 13 2024 PATTERN SYNOPSIS/FORECAST: Progressive and messy pattern across the CONUS...trough axis along the West Coast...with an upper low over the southern central Plains...and another upper low, this one in the northern stream, centered over Ontario with an attendant 996mb surface low, but with a lobe swiping through the Upper Great Lakes last evening. 850mb temps ahead of this spiking up into the teens, with highs yesterday in the mid to upper 70s over much of the area. At the surface...front drapes across the central UP into WI, with a few showers/storms along/ahead of this as of 4z/13...ultimately back to a surface low in the Nebraska vicinity...at which point the baroclinic zone turns back to the northwest along the Rockies. A bit col region-y over eastern Nebraska/IA, though. In the southern stream, much greater convective activity over the southern US in the presence of a punch of PV over OK/KS, and a surface warm front stretching along the Gulf Coast. Looking forward...northern stream PV axis slips by...with the southern stream disturbance to follow shortly thereafter, crossing the OH Valley through Tuesday night...leaving Michigan along lingering boundary/col-region between these two features in the meantime. However...another northern stream disturbance approaching for Wednesday night into Thursday should drive brief ridging back into the area for midweek...which could allow for frost potential at times. It is at this point that the outlook becomes less clear...depending on strength of an upstream ridge over the eastern Pacific. If this feature remains strong/blocky...would anticipate a stronger system to approach the Great Lakes for late week into next weekend, which would likely leave us dreary and cool, though it`s possible we could see a brief warmup ahead of this. However...if the upstream ridge is not as blocky, would look for nuisance unsettled weather to perturb the Great Lakes into late week, with a greater shot at ridging building in for next weekend (i.e., a better shot at warmer and more pleasant conditions). Will have to keep a close eye on this, particularly for purposes of ag interests, given that the growing season is well underway for most of northern lower Michigan, even up here on our little hill near Gaylord. Primary Forecast Concerns: Patchy Frost Potential Tuesday Night and Wednesday Night...Think we should be mostly clear over most of the area Tuesday, particularly as high pressure tries to seep in from the north through the afternoon into Tuesday night. With increasing subsidence, suspect we will be tapping into some drier air, though there are some weak signals for lingering boundary layer moisture that could lead to a few diurnal clouds here and there, perhaps. Setup would therefore seem rather favorable for a chilly night Tuesday night, with frost potential...though I do have some concerns... a) Signals for decoupling Tuesday night aren`t as strong as I`d like them to be for a total-tank-out situation, particularly noting the surface high won`t be totally overhead Tuesday night...which could keep things just mixed enough to preclude some of the frost potential if this idea verifies. This being said, winds should be relatively light in general (gusts likely under 15 during the day, and probably less so at night...except for perhaps where the marine layer may have some influence to keep things more unstable, downwind (on largely northerly winds) of GT Bay, etc. b) Aforementioned lingering boundary layer moisture (albeit weak) Tuesday could throw a wrench in things...as it could keep us from dropping overnight as much as it could if it were drier. Guidance isn`t overly bullish attm on the drier idea, though it`s also possible we may tap into a drier layer aloft than currently expected, which could drop dewpoints during the afternoon further than expected...and potentially set the stage for a much colder night. This being said...struggling to find guidance attm that is terribly cold for Tuesday night...and for a change, am hesitant to drop things too dramatically. This all being said...current forecast highs in the 60s across northern Lower Michigan (cooler downwind of Lake Superior over the EUP) with a typical 20-30 degree diurnal temp range would put us in the mid 30s for lows Tuesday night. If incoming wildfire smoke is able to keep afternoon highs cooler than anticipated...would not be out of the question to see lows approach freezing, particularly over the usual cold spots in the interior. Wednesday night may actually have a shot at frost as well...given that high pressure should still be around, and there may be some potential for better decoupling ahead of the next system, which should be on the horizon by Thursday morning. There will be tricky parts to this idea, too, though...as we will likely be looking at increasing mid/high clouds overnight that could reduce the amount of radiational cooling we`d otherwise experience. Otherwise...frost potential through the remainder of the period is increasingly uncertain, given the increasing uncertainty in the pattern for the remainder of the week. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 650 AM EDT Mon May 13 2024 Morning fog at CIU will burn off quickly. A slow-moving cold front will cross lower MI today. Showers and a few t-storms will re- develop in central lower MI today and tonight. MBL is the most likely to be impacted, though some showers could approach APN later today. Cloud cover will increase today, especially at APN/TVC/MBL. All of this should be VFR. Northerly breezes develop today. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ SHORT TERM...JZ LONG TERM...FEF AVIATION...JZ