Marine Weather and Tide Forecast for Pinckney, MI

AVIATION

High pressure moves east from the Great Lakes while reaching back to maintain control of conditions over SE Mi for the rest of today and this evening. A lake breeze augmented easterly wind is the weather highlight in the otherwise benign pattern of increasing high clouds.
The high clouds are the first sign of the next low pressure system organizing across the southern and central Plains which brings steadily lower conditions into SE Mi late tonight through Thursday.
VFR is expected to hold through much of the night as the initial round of showers struggle to overcome low level dry air over the region. This is followed by the primary moisture surge toward sunrise as the surface low reaches northern IL and the warm front moves toward the southern Mi border. Showers become widespread across the area during Thursday morning but have greater intensity north of PTK with a rumble of thunder possible. Ceiling drops into MVFR and then IFR as the surface low and warm front move across southern Lower Mi.

For DTW... VFR continues under increasing high clouds this afternoon and evening and then drops below 5000 ft late tonight. Showers increase coverage from the south late tonight with a rumble of thunder possible Thursday morning.

DTW THRESHOLD PROBABILITIES

* High for ceiling at or below 5000 feet after 09Z Thursday.

* Low for thunder after 12Z Thursday.

PREV DISCUSSION
Issued at 333 AM EDT Wed Apr 30 2025

DISCUSSION...

Clear skies in the wake of a cold front are now seeing temperatures drop below the 40 degree mark across most of SE MI, where frost advisories remain in place. Patchy to areas of frost will be likely just prior to sunrise. Frost advisories will drop off at 8AM EDT where late April/early May solar insolation works to quickly warm temperatures up into the upper 50s to low 60s across the interior of the cwa, but in the upper 40s to mid 50s within the lake shadow under the influence of light northeast flow. High pressure brings dry weather today.

The upper-level wave leaving the four corners region will traverse into the Texas Panhandle into Oklahoma today which will aid in the development and modest strengthening of a surface low, projected to path over southern Michigan late tomorrow into Friday morning. This will initially pivot a strengthening llj across Michigan, enhancing theta-e advection, bringing the first opportunity for precipitation very late tonight through tomorrow morning. Initial forcing will be derived from the more focused low-level system-relative isentropic ascent. The low pressure then takes aim for Michigan late in the day on Thursday with the upper-level trough trailing just behind, then supporting broad-scale ascent driven by low-level frontogenetic forcing as the elevated frontal boundary stalls with the boost in differential vorticity advection associated with the pronounced mid- level vort max tomorrow afternoon and evening. This will result in increased coverage of showers through the afternoon.Showalter indices range from 0 to -1 highlighting the weaker elevated instability present which will bring the chance for embedded thunderstorms with all activity. The potential for multiple rounds of activity including embedded thunderstorms will bring the chance for elevated rainfall totals of 1-2+ inches, which at present time looks to align somewhere across the Flint/Thumb/Tri-Cities Region or farther north into northern lower Michigan. Please see the hydrology section for additional details.

Severe weather potential will be highly conditional on daytime recovery of any morning activity. Most of the model hi-res probabilities brings low chances to exceed 1000 J/kg SBCAPE by the later afternoon and evening hours, but the energetic jet profile aloft does support some shear conducive for strong to severe storm development. If destabilization is realized, all hazard types will be possible in the late afternoon and evening hours until a cold front sweeps through. Storm mode can range from pulse turning to more linear bowing segments with unidirectional wind direction above the near surface. Again this is highly marginal at this time and outside of the NAM, supporting evidence in hi-res output is on the lower side.

Uncertainty regarding precipitation trends increases greatly over the weekend into early next week surrounding evolution of the longwave pattern. The ECMWF/AIFS/EPS mean highlights a secondary trough that drops through the plains into the Ohio Valley Friday into the weekend, stalling and closing off with a deep ridge across the Atlantic blocking off open flow. This would bring additional chances for rain showers over the weekend into early next week as opposed to the more progressive GEFS solution which stalls the upper-level off the coast of New England. Will retain a low (20% or less) PoP values through this period until the aforementioned wave is sampled and better convergence within model output is observed.

MARINE...

High pressure has expanded across the region overnight and will hold through the day. The next low pressure will develop over the Mid MS Valley Wednesday night and will lift through lower MI Thursday and Thursday night. The precipitation will begin Wednesday night ahead of the approaching warm front that will lift through Thursday with the cold front following overnight. The low will not be very strong but will be strengthening while lifting through the region. Wind speeds are not expected to be too elevated with a lack of cold air advection, holding mainly at or below 25 knots. Thunderstorms will be possible Thursday into the overnight. A second cold front will drop through the region on Friday but will be followed closely with an area of high pressure building into the area for the weekend.

HYDROLOGY...

Arrival of a low pressure system will bring widely scattered to widespread showers with embedded thunderstorms on Thursday. Multiple rounds of thunderstorms capable of producing heavy downpours will bring the chance to see rainfall totals between 1 to 2 inches across Southeast Michigan, with the Flint, Tri-Cities, and Thumb region having the highest probabilities of seeing these elevated totals, pending the final track of the low pressure system. Rainfall totals in excess of one inch cannot be ruled out across the Metro region with any thunderstorms, but basin averaged rainfall totals are forecasted to range between a half-inch to an inch. Highly localized flooding in low-lying and/or flood prone locations will be possible.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.