Marine Weather and Tide Forecast for Harbor Springs, MI

SHORT TERM /THROUGH TONIGHT/
Issued at 302 AM EDT Mon Jun 16 2025

PATTERN SYNOPSIS/FORECAST:

Broad ridge axis over the central US...stretching from Manitoba to New Mexico...with southwest flow across the western US aiding in eastward advection of elevated mixed layers into the Plains (even Upper Midwest). Disorganized troughing hangs on over the MS Valley into the eastern US to our south...with the OH Valley still remaining a boundary between very moist air (pwats greater than 1.5in) and less moist air, as return flow remains quite persistent across the Gulf Coast...though some of the moisture is sneaking up into the northern Plains and Manitoba
Here in the Northwoods
we remain between a couple weak surface fronts...but high pressure over Ontario remains persistent...with continued low-level easterly flow reinforcing the dry air mass across northeast Lower MI and the EUP.

Expect upstream system to begin to organize to our west Monday...with increasing return flow allowing for increasingly warm and moist air to enter the region...leading to some potential for showers and storms, though the more organized activity should remain upstream from us. Actual surface low itself should remain to our northwest through Monday night...tracking just north of Lake Superior going into Tuesday...dragging a boundary into the region with continued chances for showers and thunderstorms. Another shortwave crossing the western/central US will aid in development of another surface low along this same boundary going into Wednesday...with this system tracking through the Great Lakes region for midweek, keeping things active
By late week
ridging looks to build in from the west as sharp troughing digs into the western US...ultimately resulting in potential for unsettled, and perhaps warmer, weather to continue into the upcoming weekend.

Primary Forecast Concerns through Tonight:

Temperature trends...Incoming air mass should be a little warmer than yesterday's, supporting highs reaching into the lower 80s across most of the area. Cloud cover across the eastern UP/Tip of the Mitt should lead to a bit cooler temps up that way...and do think mid clouds moving into the region will, similar to yesterday, be enough to keep temps a few degrees cooler than we might be with maximum insolation
However
if we do end up mixing more deeply and/or getting more clear skies than expected (most likely across NE Lower and toward Saginaw Bay), some locations could crack the mid 80s for highs.

Shower/storm potential...while moisture/warmth should be on the increase overall...still think high pressure and low-level easterly flow will be clinging to our area enough to keep unsettled weather at bay...or at least, limited, into the start of the work week. Air mass yesterday, per 00z sounding, was rather dry and well-mixed through 800mb...and think we will be tapping into this environment more than a moist one, which has potential to limit the amount of afternoon activity we end up getting...particularly if we remain cloudy enough to keep us from realizing maximum diurnal heating.
Weak flow over much of northern Lower suggests development of lake breezes during the afternoon, which could serve as a focus for some popcorn storms to try to pop
though again
still question how much instability will be present to do so...unless we end up moistening up far more aggressively than expected. Think our better chance for activity may be tonight into Tuesday morning, depending on any development upstream.

LONG TERM /TUESDAY THROUGH SUNDAY/
Issued at 302 AM EDT Mon Jun 16 2025

Primary forecast concerns into next weekend:

Shower/storm potential through the week...A fair bit of uncertainty attm in the timing/position of the cold front Tuesday, which lends some concerns for us. Faster progression, with the front more or less over us to start the day, could keep temps down and punt the best chances for afternoon redevelopment across southern Lower MI. Slower progression could leave us much warmer Tuesday and open us up for better destabilization and increase potential for activity to develop either overhead or move in from the west. Still have concerns in the back of my mind that the focus for better shower/storm development ends up sticking to our north, perhaps scraping the Yoop, as the boundary stretches out over us through the day. Winds do look a smidgen better by Tuesday...which could indicate a boost in shear and better potential for storm organization...though it remains unclear if we will be warm/moist enough to overcome potential capping in the mid-levels. Not a clear forecast by any means.

Wednesday, attm, appears more interesting...as an upper low induces a wave along the lingering boundary, which should track up toward us. Increasing synoptic lift with a potentially more well-defined system, combined with an increase in deep moisture, suggests a better shot at widespread precip along/north of the lingering boundary. Currently, some part of northern Michigan appears to be in a favorable position for best co-location of forcing and deep moisture, which leaves a threat of heavy rain in play for Wednesday...though still unclear where the axis of heaviest rainfall will end up...with rainfall totals of at least an inch possible somewhere across the area when all is said and done Wednesday. Winds with this system should be a little better as well, suggesting better shear, suggesting a better shot at severe weather, though for now...think the best chance of this looks to stay to our south, but it will be close enough to warrant keeping an eye on things.

Late week
as ridge rebuilds to our west
will need to keep an eye out for additional activity to develop upstream and perhaps track into the region. Winds are a little better with this latter system, which should be more favorable for convective development than what we've been experiencing recently. SW flow also suggests a much better shot at instability/elevated mixed layers slipping into the upper Midwest...which bears watching for both organized convection as well as heavy rain potential. (This idea also decreases certainty in potential for warm temps again late week...as convection could keep us from realizing maximum diurnal heating yet again.)

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
Issued at 643 AM EDT Mon Jun 16 2025

VFR. Some decaying showers/storms will try to push into eastern upper MI late tonight, but better chances for rain will reach CIU/perhaps PLN after 12Z. Today, just some cu and patchy mid clouds, with an isolated shower possible. Light, mostly southerly breezes today/tonight. The breeze should be enough to prevent fog tonight.

APX WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...None.