textproduct: Gaylord

KEY MESSAGES

- Continued early growing season frost/freeze concerns tonight and again Monday night/Tuesday morning.

- Precipitation chances return Tuesday/Wednesday.

- Moderating temperatures for the latter half of the week... maybe some precipitation chances for the weekend?

DISCUSSION

Issued at 315 PM EDT Sun May 10 2026

Pattern Synopsis/Forecast: Blocked large scale pattern that has plagued the Great Lakes for the entirety of May continues...with eastern North America stuck on the backside of an expansive omega block that spans the Atlantic basin. Upper low spinning over James Bay has several dynamic PV anomalies rotating around it...a couple moving into the upper Lakes from the northwest per water vapor imagery. Deep layer northwesterly flow continues with low/mid level cold air advection...-8C 850mb temperatures creeping into Lake Superior. Weakly cyclonic boundary layer flow across the Great Lakes in the wake of a 994mb surface low over northern Quebec... 1025mb surface high straddles Saskatchewan/Manitoba with ridging extending into the northern Plains.

But there is a (short) reprieve on the way from persistent long wave troughing across the Great Lakes this week...with some bona fide height rises/short wave ridging Monday. This will be followed quickly by a Pacific-origin short wave trough later Tuesday into Wednesday; this trough axis is expected to shift toward the east coast in the Thursday/Friday time frame and brings back some quasi- zonal flow. A lot more spread in the forecast pattern evolution develops by next weekend...mostly tied to whether or not Pacific short wave trough gets kicked east quickly...or drops into the southwestern U.S. (probably the preferred idea at this point).

High pressure over the Canadian prairies forecast to build southeast into the Midwest/Great Lakes Monday. Approaching short wave trough will drag an Alberta Clipper across Michigan Tuesday night/ Wednesday. So one day of southerly boundary layer flow but not enough for an appreciable air mass moderation before cool northwest winds return Wednesday. High pressure does return for Thursday... and stronger return flow for Friday but the uncertainty in the upper level pattern also has implications farther down with some implication of a frontal passage (or at least a front in the vicinity) next weekend.

Primary Forecast Concerns:

Continued early growing season frost/freeze concerns tonight and again Monday night/Tuesday morning: Primary issue for tonight will be one of cloud cover. Even with the loss of diurnal Cu field suspect there is still going to be some lingering clouds (and maybe a few showers) across northern Lower into this evening. Eventually do think that clouds will thin sufficiently with diminishing winds to allow temperatures to drop at/below freezing most areas. Will likely go with a Freeze Warning for all northern Lower zones...could get cute and pop a few spots such as the Leelanau Peninsula into just a Frost Advisory. Anticipate areas across interior northern Lower to drop into the 20s overnight. A somewhat similar frost set up for Monday night/Tuesday morning though the best cooling will be during the first half of the night with winds and clouds increasing late.

Precipitation chances return Tuesday/Wednesday: Clipper system arrives across the upper Lakes Tuesday which is expected to push a widespread band of rain across the forecast area. Strong warm advection/isentropic ascent on the front side of this system aided by some low/mid level frontogenesis acting upon an axis of higher precipitable water (up to 1 inch) and theta-e. Rain amounts 0.25 to 0.50 inch expected in general during the day Tuesday...perhaps some thunder as well later Tuesday/Tuesday night along theta-e ridge. Shower chances will linger Wednesday as deep layer moisture wraps around the departing system and back across Michigan.

Moderating temperatures for the latter half of the week...maybe some precipitation chances for the weekend?: Temperatures expected to warm Thursday closer to near normal highs (63 to 67 degrees)... probably a better chance of exceeding normals on Friday with some stronger southerly flow (daytime highs have been below normal every day this month save the 4th of May). Could see highs return to the 70s across northern Lower on Saturday...but a lot of uncertainty at that point. That uncertainty is also going to result in a lot of nuisance PoPs in the forecast from Friday through Sunday.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 111 PM EDT Sun May 10 2026

Cigs float between 3000-5000ft today, though likely prevailing VFR with occasional dips to MVFR. Clouds most likely diminish overnight...and redevelop around mid-morning Mon, likely VFR again. Low chance for IFR/BR(?) to develop at CIU late tonight (9-12z) but not confident enough attm to include in TAFs. VCSH/SHRA (mix with SN at PLN/CIU?) possible this afternoon, with TS possible at times, esp between 20-02z at APN. Generally NW winds 5-15kts today gusting 15- 25kts (could be as high as 30kts at MBL this afternoon?)...dropping into to light/vrb overnight with land breezes likely at coastal TAF sites. Winds more NNW to N to start Mon, remaining light with high pressure in vicinity.

APX WATCHES/WARNINGS/ADVISORIES

MI...Freeze Warning from midnight tonight to 8 AM EDT Monday for MIZ016>018-020>036-041-042-099. Frost Advisory from midnight tonight to 8 AM EDT Monday for MIZ098. MARINE...None.