Marine Weather and Tide Forecast for Grosse Pointe Woods, MI

AVIATION

Period of clear sky exists early tonight, as a brief window of dry low level northwest flow maintains control. Gradual veering of low level flow with time overnight and early Wednesday will draw lake moisture back into the region. This will support an increase in cloud coverage during this time. Cloud base initially at lower VFR, but some reduction to near MVFR remains plausible by Wednesday morning as warming atop the inversion begins to lower the inversion base. Broken coverage of stratus likely to linger into the afternoon, before the modest warming as low level winds settle to southwest favor a clearing trend toward Wednesday evening.

DTW THRESHOLD PROBABILITIES...

* Low for cigs aob 5000 feet tonight. Medium Wednesday.

PREV DISCUSSION
Issued at 258 PM EST Tue Jan 14 2025

Visible imagery this afternoon highlights that a good amount of sunshine has broken out in the subsidence region behind the departing shortwave. Will likely observe varying amount of clouds throughout the remainder of the daylight hours. West flow tonight with nocturnal cooling is expected to result in enough saturation for stratocumulus development. Supersaturation with respect to ice within the cloud bearing layer at -10 to -11C will likely support some ubiquitous flurries. Clouds are expected to begin the day Wednesday before warm advection scours out the moisture. Probably will set some early evening minimums Wednesday evening before southwest winds increase.

Exit region to upper level jet impulse now at supergeostrophic position of western North America ridge will dig into the Great Lakes late Wednesday and early Thursday. Models show increasing cyclonic curvature to the composite trough axis which is expected to result in a corridor of low-midlevel convergence here across Lower Michigan. Problems with the setup overall include, extremely quick movement of the synoptic convergence, little to no preceding isentropic ascent, and warm thetae/moisture lagging the forcing.
Best frontal forcing will be centered around 700mb associated with a low pressure circulation at 12Z. Good saturation through the DGZ occurs for a time, but dry air pushes downward in the column to around 4.5 kft agl in the subsidence wake. Collection of EPS and hiresolution NWP suggests a 10-16Z time window on Thursday for light snow. Will attempt at tightening the time mention in the grids and increase PoPs into the likely category. Lack of duration to deeper moisture limits snow amounts to an inch or less.

Split upper level flow with rising geopotential heights will govern the weather late Thursday and Friday. Forecast soundings support quiet weather with strong static stability between 1.5 and 8.0 kft agl. Relatively comfortable daytime conditions with temperatures in the lower to middle 30s.

Phasing of the northern and southern stream will have the potential to direct an areas of frontogenesis across Lower Michigan on Saturday. Overall predictability of the event appears to be dependent on timing/details how southern stream shortwave energy ejects out of Texas ahead of the northern stream potential vorticity trough. Guidance has not become settled enough to offer much commentary. EPS/GEPS/GEFS cluster analysis shows as many as 6 different solution clusters although its interesting to note that most of the clusters do offer some precipitation amounts. 00Z EPS data is showing approximately 30 percent of the solutions at less than 1.0 inch at DTW. A period to monitor.

The big story of the extended is the cold air mass that will likely be in residence during the early portion of next week. Latest EPS data exemplifies a remarkably lower amount of variance for daytime highs Monday and Tuesday. Mean values suggest daytime highs in the single digits above zero, some 20 to 25 degrees below average.

MARINE...

A ridge of high pressure will briefly fill in over the Great Lakes late tonight and into tomorrow which will moderate wind speeds and gust potential through tomorrow morning. A southern extension of a clipper system will then move through the northern Great Lakes late tomorrow night into Thursday morning. Expansion of this system into the region will back wind direction to the southwest. The favorable fetch will again provide a window for elevated wind speeds and gust potential, especially through the Saginaw Bay and into central Lake Huron, where sustained winds of 20 to 25 knots, gusts up to 30 knots, will be likely. This system also bring widespread light snow to all of the Great Lakes. Passage of the clipper veers wind direction back to the northwest on Thursday.

PREV DISCUSSION...
Issued at 254 PM EST Tue Jan 14 2025

DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.