Marine Weather and Tide Forecast for Constantine, MI

DISCUSSION
Issued at 310 PM EDT Sun May 11 2025

The high pressure center keeping the area dry reaches the northeastern US this afternoon/evening and this allows warm air advection to begin to take over tonight into Monday. With the weakness in the flow, upper low trapped to our south during this dry period starting at the end of last week begins to travel northward on Monday. Increased moisture (we're already beginning to see pockets of 50 degree dew points this afternoon in our south), moves in on the outer fringes of the arriving upper low. With this in mind, am a little bit more inclined to bring in slight to chance PoPs as early as midday in our south on Monday even despite the antecedent dry air. Given the enhanced moisture profiles and some modest instability, can't totally rule out some embedded thunder Monday evening.

As the upper low pressure center moves closer to the area for Tuesday, it appears that a dry slot works in later Monday night into Tuesday morning. But with vorticity around from the upper low and increasing low level lapse rates, wouldn't be surprised to see afternoon pop showers and storms perhaps due to differential heating, especially with our area on the northwestern end of the moisture stream off the western Atlantic. While minimal shear is still expected to limit overall severity of storms, slow storm motion and convective elements of cells may allow for locally heavy rain. For Wednesday, the upper low continues to wash out as the next trough advances towards the area, but it still leaves enough vorticity around to help set off more summer-like afternoon showers/storms. High temperatures in the 70s will continue into midweek with low 80s also being possible.

The next trough contains a deep upper low and that pushes towards the area for Thursday. This orientation makes it much more conducive to introducing shear to the situation so if thunderstorms are able to form later Thu/Thu night, the severe potential is better. Mid level ridging is notable across the area as is low to mid level RH so there is some question about if debris clouds may be able to limit development of convective energy during the day Thu. 7 to 8 C/km mid level lapse rates move through the area later Thursday and vacate the area before the overnight period. DCAPE values approach 1000 J/kg. This would allow for the possibility of both wind damage and large hail. Additionally, better effective helicity values are being shown, which could allow for some rotation meaning a tornado threat could exist. SPC has continued with their slight risk of severe weather area for this period. It is interesting to see 850 mb temperatures forecast to reach 18C Thu, which when mixing is maximized often leads to 90F high temperatures. According to a plot on Iowa State Mesonet's page, Rochester rarely (since 2003), sees 90 degrees in mid May so that would be early if it is realized.

With a cold front moving through later Thu night, this likely keeps Friday devoid of showers/storms, but the front is then expected to stall out not too far from the area. The ECMWF/GFS camp indicates some rain/storms could be possible Friday evening scraping our southern 1 to 2 rows of counties as a low level jet reinvigorates to our west on the southern side of the aforementioned upper low that slowly heads towards the upper Great Lakes.

Next weekend looks dry again as weak high pressure follows on the heels of the departing upper low.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
Issued at 731 PM EDT Sun May 11 2025

Predominantly VFR conditions at the TAF sites through the period, with light to moderate east to southeast flow. A disturbance lifting southeast to northwest will build in Monday afternoon-evening bringing chances for showers and perhaps even an isolated t-storm. There are differences in timing/placement of the better precipitation, so mainly have prob30 groups in the 18-00z time frame Monday to handle this. Best chance for actual impactful showers [MVFR most likely] and isolated thunder is at KFWA, especially 21-00z.

IWX WATCHES/WARNINGS/ADVISORIES
IN...None.
OH...None.
MI...None.
MARINE...None.