textproduct: Detroit/Pontiac

KEY MESSAGES

- Widespread freezing rain and wintry mix for much of Southeast Michigan Friday. Ice accumulations between a tenth and two tenths favored. Around an inch of snow and sleet mix possible in the northernmost portions of the Thumb.

- Arctic cold front late Sunday with strong northwest winds appearing likely Sunday night and Monday.

- Below normal temperatures to start next work week.

AVIATION

Low clouds associated with the Ohio Valley low pressure have drawn south, but some MVFR VSBY restrictions have developed under the clearing. These should clear up with sunrise. Wind fields turn north to northeast throughout today and will usher in a low stratus deck currently working through northern lower Michigan aided by Lake Huron moisture component. Low clouds will bring MVFR to IFR ceilings with IFR more likely across MBS and FNT. Daytime mixing will try and lift ceilings out of IFR during the afternoon. Winds veer toward the east this evening into tonight bringing a break in lower ceilings. Freezing rain potential increases tomorrow morning. Highest chances move in just beyond 12Z tomorrow morning.

For DTW...Low clouds look to expand across DTW today bringing predominately MVFR ceilings before clearing out this evening into tonight. Probability is high for freezing rain/drizzle to impact the airspace tomorrow morning starting shortly after 12Z. Freezing rain is expected to last through the morning and possibly into the early afternoon.

DTW THRESHOLD PROBABILITIES...

* High for ceiling 5000 feet or less by late morning and through the afternoon. Low tonight. * High for freezing rain tomorrow morning.

PREV DISCUSSION

Issued at 312 AM EST Thu Dec 25 2025

DISCUSSION...

Quiet weather for Christmas Day as high pressure sliding over northern Ontario sends a dry backdoor cold front through SE MI this morning-early afternoon. Southern half of the region will be able to see highs in the upper 30s with low 40s toward the Ohio border whereas the northern half, seeing the earlier push of cold advection, hold closer to the mid 30s. This cooler near-surface airmass as sets the stage for the next shortwave ejecting out of the Plains and into the Great Lakes late tonight-early Friday.

While a few light snow showers are possible over the northern Thumb late tonight as its clipped by the lead arm of isentropic aided by left exit region jet dynamics, little to no accumulation is expected. Instead the main associated precipitation overspreads SE MI between 7-10Z and persists into the afternoon. Confidence remains high that the surface warm front will fail to lift into SE MI or only partially push into southern Lenawee-Monroe at best due to persistent cool east-southeast at the base of the aforementioned high as well as the favored low track over northern IN/OH. Result is fairly high confidence in the p-type forecast with freezing rain being predominate for the bulk of the CWA outside of areas north of M-46 in the Thumb. For these areas, snow looks to hold as main type however forecast soundings are a bit more aggressive at attempting to get a shallow warm nose of 1-2C at ~5kft which offers sleet wintry mix potential. As noted in prior forecast cycle, the main issue now is QPF. The dichotomy between the coarser global/regional models vs a good portion of the high-res models continue to be seen in the latest 00Z runs. The GEFS/CMCE/EPS means and their deterministic models still are holding to robust amounts of 0.25- 0.4" centered either over the central or northern portions of the CWA. High res solutions, while still carrying noteworthy variation (ie compare 00Z Nam Nest-HRRR-ARW-NSSL), generally favor a more southerly QPF footprint as well as being being leaner at around 0.1" as a whole. 00Z HRRR/ARW are even more extreme advertising only a few hundreths for most of the area. This stems from these solutions favoring greater ascent on the lower portions of the frontal slope across either southern SE MI or northern IN/OH reducing available moisture further up the slope over the central/northern portions of the CWA.

While there still are the stark differences, decided to hedge a bit more towards the higher-res model camp for this forecast cycle and cut down running QPF towards 0.15-0.2". This results in a reduction in forecast ice accumulations down closer to around 0.1-0.15" for most areas. For the snow side of this system, the Thumb resides under the left exit region of the western Great Lakes jet max throughout the day which keeps more persistent light to perhaps brief moderate precip rates through the afternoon (even in the drier high-res solutions). Signal for more sleet to mix in will cut into potential snow accumulations however- forecast totals around 0.5-1". With the high uncertainty in QPF, opted against headlines in this forecast package to allow a chance to see if convergence in solutions begin to manifest in the 12Z cycles.

Mid-level ridging follows in the wake of the low for Saturday bringing drier weather as well as the start of milder air as southerly return flow raises 850mb temps from 0-1C in the morning to 6-7C by evening. Saturday highs don't fully realize this warm advection given mildest air arriving in the evening, instead topping out towards the mid-upper 30s, however it does allow for widespread 40s and perhaps near 50 in the far south Sunday. Respectable mid- upper Pacific Northwest trough arrives over the central CONUS daytime Sunday supporting rapid cyclogensis over the Midwest. This deepening low is progged to lift over the Great Lakes late day bringing widespread rainfall with a backedge changeover to snow as its associated cold front sweeps through Sunday night. Strong cold advection follows as the trough allows a portion of arctic air of northern Ontario to drive south over the Great Lakes likely generating gusty winds near or in excess of 30kts (35mph). Highs to start the new work week remain in the 20s as thermal troughing lingers. This colder, windy setup also supports lake effect snow showers/snow squalls pushing into SE MI.

MARINE...

High pressure will continue to push eastward across the James Bay region through the day on Thursday. Lighter winds will continue through the morning before northerly flow increases going through the day as a low pressure system begins to move towards the region. This will bring elevated wave heights along the Lake Huron shoreline. Small Craft Advisories may be needed Thursday into Friday given the favorable fetch increasing wave heights. The shift to easterly flow overnight Thursday will also bring some stronger gusts with wind gusts ranging between 20 to 30 knots across Lake Huron. Easterly flow will persist through Friday as a low pressure system brings in wintry precipitation to the region.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 10 PM EST Friday for LHZ421-441>443.

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