Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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567 FXUS63 KAPX 041847 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 247 PM EDT Tue Jun 4 2024 .KEY MESSAGES... - Scattered to numerous thunderstorms on Wednesday. - Unseasonably cool with shower chances late week into weekend. && .SHORT TERM /THROUGH WEDNESDAY/... Issued at 208 PM EDT Tue Jun 4 2024 Pattern Synopsis and Forecast: Potent, elongated and or messy, upper trough and subsequent low pressure system centered over southern Saskatchewan-Manitoba will be the focus for this upcoming period. Southern short wave either associated with, or advecting along the southern periphery of the parent upper low, will swing through the Great Lakes Region during the day on Wednesday. This short wave, warm (very) moist advection early on Wednesday, and an approaching cold front will facilitate an environment favorable for thunderstorm development throughout the day as the parent upper low and sfc low move east across southern Canada. Cooler temps on the way behind this frontal system. Primary Forecast Concerns: Any isolated convection early this evening will diminish shortly into the overnight hours. Next system in the form of a short wave trough and cold front will move into the region largely on Wednesday with scattered to numerous thunderstorms thanks to dewpoints surging into the mid 60s, weak to modest instability, and ample lift. Largely expecting these storms to be general thunderstorms due to the combination of only modest instability and shear but cannot rule out a stronger storm or two with gusty winds. Progged soundings (and Plainview 2D maps) do show PWATs well into the 1.5" to 1.8" range, which would easily be a daily record according to the spc sounding climatology page. In fact, model soundings show a very favorable environment for efficient, heavy rain with these storms due to the following: skinny CAPE, very high low to mid RHs (80-90%+), and a relatively deep warm cloud layer. Only thing working against this environment is the quicker storm motions, but any training/additional development aside from along the cold front could produce locally heavier pockets of rain. On the bright side, this should be a good wetting rain for a good chunk of the area. Not really too many other hazards/impacts with this system other than lightning, pockets of heavy rain, and maybe some isolated gusty winds, but temperatures will be on the decline behind this frontal system. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Issued at 208 PM EDT Tue Jun 4 2024 Pattern/synopsis: An upper low, which initially develops over s central Canada, will move/evolve into the Great Lakes area. And here it will sit, and sit, and sit a little longer. Forecast: Unseasonably cool and, at times, showery wx will persist for the bulk of the long-term forecast. Thursday into Friday into particular look soggy, as the upper low moves directly overhead. This will combine with abundant moisture, and any contribution from weak diurnal heating, to result in showers (and a few t-storms on Thursday). Though the core of the upper low shifts toward Georgian Bay and Lk Ontario this weekend, significant troffing lingers back into the northern lakes. This will maintain some showers, with a diurnal contribution/amplification in the afternoon and evenings. As we head into early next week, the upper trof pivots toward the southern lakes and northern OH Valley. That allows heights to start to rebound, with temps starting to do the same, and eventually pops will slacken. How cool will temps be Fri/Sat? There is plenty of model guidance that keeps readings in the 50s in at least the eastern UP and higher elevations of northern lower MI. Most of our blends are a little warmer than that. Any sort of diurnal heating at all will push readings higher and fast (it is still June). The idea of a diurnal temp swing of less than 10f seems kind of difficult...but we did manage it just a week ago, on a rainy/cold advection Memorial Day. Have taken max temps down a hair on Fri/Sat. Min temps won`t depart too far from normal during the long term period, but max temps will. Highs mid 60s to mid 70s Thu, but then mid 50s to mid 60s Fri-Sat. Hopefully a gradual rebound after that, with 60s Sun, near 70f Mon, in the 70s Tue. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 109 PM EDT Tue Jun 4 2024 Increasing confidence in generally dry conditions through the afternoon, although the most likely area to see an ISO -SHRA or -TSRA will be in the vicinity of the Tip of the Mitt and eastern upper, but not too terribly confident. Southeast winds through the afternoon and into the overnight, 5 to 15 KTs. CIGs begin to decrease from the southwest to northeast Wednesday morning and midday, becoming MVFR and IFR across KMBL and KTVC. In addition, RA and TSRA expected between 09-15Z west of I-75, spreading eastward into the midday to afternoon hours. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ SHORT TERM...JLD LONG TERM...JZ AVIATION...JLD