Marine Weather and Tide Forecast for Greilickville, MI

DISCUSSION
Issued at 320 AM EDT Sat Jun 13 2026

PATTERN SYNOPSIS/FORECAST:

Broad troughing across the central continent tonight...bookended by slight ridging just off the PacNW and an attendant sharp shortwave trough over WA/ID...and sharp ridging across eastern Canada ahead of Thursday's punchy PV. 540dm upper low just south of Hudson Bay (attendant occluded surface low over Hudson Bay) with elongated trough axis stretching back across central/southern Canada, with strong N flow and much colder air (0C 850mb isotherm over central Canada)... compared to +16C at 850mb across the southern Plains beneath a broad ridge axis. In between, zonal flow aloft (100kt upper jet) and scattered perturbations stretching from MT through MN up into Ontario along a surface cold front. Most of the moisture (Pwats pushing 2in or more) is across the southern US and East Coast attm, near and south of a boundary stretching from TX to WV to VT...though strong flow with the upper low resulting in some moisture (pwats around 1in) wrapping back around through central Canada and into the Upper Midwest. Steeper lapse rates across the western US associated with elevated mixed layers...but 500mb cooling across the northern tier of the continent, atop some slight 700mb warming over SD/MN, likely to result in weakening stability across the Upper Midwest along aforementioned zonal boundary. (A little convective activity noted with this at 0z.) A little convection over the EUP associated with a subtle PV max tracking through the area as of 0z as well. Lingering convection across the EUP and over western Lake Superior seems to be draping some subtle outflow boundaries southward with time as of 3z.

Upper low looks to hang around Ontario/eastern Canada through the bulk of the period, likely resulting in periods of cooler and active weather over the next several days. A subtle wave swings across the Upper Great Lakes today, stretching a zonal boundary across the area which could become the focus for periods of rain (heavy rain?). A more notable shortwave trough digs in tonight and early Sunday, sweeping a cold front through and bringing blustery, cool, showery NW flow to the region to wrap up the weekend. Additional energy wraps through the Upper Great Lakes Sunday night and Monday...likely keeping things cool going into early next week. Greater uncertainty comes into play going into Monday night/Tuesday, pending the evolution/timing of another lobe of PV swinging around the upper low into the Upper Midwest...though broadly, signals point toward surface pressure falls across the Upper Midwest/Great Lakes as early as Monday night into Tuesday...and a potential increase in SW flow going into the early/middle portion of next week...especially with guidance suggesting additional energy diving in from the west will trigger cyclogenesis over the central US. Quite a bit of uncertainty in how this plays out as well, and will need to be monitored in the coming days, as it will likely determine conditions for the latter part of next week as well.

FORECAST DETAILS...

Heavy rain potential today...generally slow-moving WSW-ENE oriented boundary draping across the area will serve as a focus for activity today. Flow through most of the column will largely parallel this boundary, which brings concerns for heavy rain into play...as setup should be more favorable for cell training, though it would be more favorable if the LLJ was a little more perpendicular to the boundary than guidance currently shows...and do worry about stronger flow aloft keeping cell motion a bit quicker than a textbook frontal heavy rain event. Slow-motion of the boundary should also lend to the opportunity for multiple waves of rain to hang out over a particular area for a prolonged time, though. As of 5z, there seems to be a bit better training/multiple waves of convection across southern MN (though precip over northern WI is starting to congeal into an east-west line), and do worry this could signal a more southward shift in the focus of both this morning's convection/heavy rain threat...as well as some of the activity later in the day (or at least, lend some potential for the better instability, moisture, and therefore, convection, to remain to our south); signals for best pwats (1.5+in) look to stay to our south and southwest as well.
However...the PV slowly draping in from the northwest today keeps the door open for more focused lift remaining a little further north, with signals for pwats to remain at or above an inch in this region. Ultimately, exact threat area for the heavier rain will likely remain unclear till it starts to unfold, especially depending on how far south the boundary progresses today. Further south would likely shunt the threat for heavier rain tonight to our south, while further north could keep heavy rain in play for areas near and south of M-72...whereas the heavy rain threat during the day today should largely be near and north of M-72.

Strong storm potential today...best instability will likely remain to our south, especially if this morning's convection leaves things too cool/stabilized through the afternoon. However, if we do destabilize/clouds break up today...500 to perhaps as much as 1500J/kg or so of MUCAPE is possible along and ahead of the WSW-ENE oriented boundary across the area as some weaker stability aloft spreads in...and best theta-e advection should be across NE Lower, especially from mbL/CAD to APN or OSC, where there is a better shot at instability becoming surface-based this afternoon. Deep layer shear in excess of 40kts across much of the area today indicates potential for storms to become organized; with flow/shear largely parallel to the boundary, think things will tend to grow upscale with time. Weakening stability aloft suggests a threat for hail, particularly with slightly cooler temps aloft than earlier in the week...and some signals for drier layers aloft this afternoon suggest evaporative cooling and potential for damaging winds to be a concern, especially with upscale growth. Flow looks to generally be unidirectional, which could also suggest a hail risk with splitting supercells if any develop...though not impossible some veering with height will occur off the deck that could lend to rotation and a threat for tornadoes with any surface-based cells...but think this threat is very low.

Moderate to high swim risk today... expect it will be breezy again today with WSW winds, especially for the first half of the day, running 10-15kts or perhaps a touch more. (Winds look to turn more NW later, especially across the Yoop.) Wind gusts largely running between 20-30kts today...though guidance signals the LLJ should ramp up above 40kts into this morning as it crosses the area. This does have me a bit worried we could end up with wind gusts 35-45kts or perhaps a little better at times, especially through midday...but the trick is getting that to actually mix down (thunderstorm convection notwithstanding), given its strength may largely be tied to the strength of the low-level inversion around 900mb. Either way...not a great day to be in the water. Winds look to diminish tonight into Sunday but pick up again Sunday afternoon around 5- 10kts with gusts around 20kts, which should keep some moderate swim risks in play, especially where W/NW fetch will aid in enhancing wave heights.

Seasonably cool Sunday/Sunday night...With the 0C 850mb isotherm swinging through, expect temps will struggle into the 60s (would not be surprised if it stays cooler across the Yoop and parts of interior northern Lower with potential for an instability cu/stratocu deck and attendant showers to form)...signaling low temperatures likely hitting the lower to middle 40s Sunday night.
For now, with pressure gradient strengthening and return flow starting to approach from the west...think parts of the area could be spared bottoming out too much colder...though still wonder about some of our interior higher terrain cold spots, especially near and east of I-75, managing to drop into the upper 30s if winds diminish more than expected. This idea could hang on into Monday night if the next wave of energy ends up slower than current expectations suggest.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
Issued at 638 AM EDT Sat Jun 13 2026

Rounds of showers and a few TSRA thru the forecast. Mainly VFR expected regardless, though brief restrictions (vsby and cigs both) are possible. The best chance of cig restrictions is at CIU. Vsbys restrictions in brief heavier rain (and TS) is at the northern lower TAF sites.

Gusty sw winds, becoming ne heading into tonight.

APX WATCHES/WARNINGS/ADVISORIES
MI...Beach Hazards Statement through this evening for MIZ016-095- 096-098.
MARINE...Small Craft Advisory until 6 PM EDT this evening for LHZ345>347.
Small Craft Advisory from 11 AM this morning to 8 PM EDT this evening for LHZ348-349.
Small Craft Advisory until 8 PM EDT this evening for LMZ323- 342-344.
Small Craft Advisory until 4 PM EDT this afternoon for LMZ341.
Small Craft Advisory from 10 AM this morning to 6 PM EDT this evening for LMZ345-346.
Small Craft Advisory from 11 AM this morning to 4 PM EDT this afternoon for LSZ322.