textproduct: Detroit/Pontiac

KEY MESSAGES

- Near record cold conditions today and Friday with wind chills ranging between -5 and 10F until Friday afternoon.

- Below normal temperatures persist this weekend and into next week.

- The next chances for light snow will be Friday night and Sunday with only a 10 to 40% chance to exceed 1 inch.

AVIATION

Notably drier conditions will exist today as arctic settles over the region. With that, ongoing lake moisture flux in northwest flow will maintain some degree of VFR cloudiness at times today. Forecast will highlight the likelihood for variable coverage between a scattered and broken condition. Some gustiness to northwest wind this morning, before diminishing through the latter half of the day. Any lingering cloud will vacate the region with the loss of daytime heating, supporting a mainly clear sky tonight outside perhaps some thickening cirrus.

DTW THRESHOLD PROBABILITIES...

* Medium for ceiling at or below 5000 ft at times through this afternoon.

PREV DISCUSSION

Issued at 404 AM EST Thu Dec 4 2025

DISCUSSION...

Longwave troughing over the Great Lakes and NE CONUS is reinforced by the amplified upper wave passing overhead this morning. Frigid conditions are settling in this morning with 925mb temps falling to the -13 to -15C range. Sfc temps in the teens at daybreak will only recover a few degrees by this afternoon as cold advection continues through the day. Current forecast highs in the lower 20s will challenge record low max temps across the area. Persistent northwest wind around 15 to 20 mph caps wind chills in the single digits. Meanwhile, post- frontal drying and subsidence will offer increasing potential for periods of sun for most of the area. The exception will be the Thumb, downwind of the Superior-Michigan- Saginaw Bay connection that will likely maintain a degree of lake cloud and some flurries. Very cold conditions tonight as wind weakens, allowing for lows in the single digits.

Southwest return flow behind departing high pressure ensues Friday to boost temperatures slightly, with highs reaching the mid 20s. However, 15 to 20 mph wind will again keep the wind chill lower in the teens. The next shortwave in the active pattern passes through the region Friday night offering the next opportunity for light snow. The bulk of the ageostrophic response and ascent with the associated jetlet aloft will be focused north of the area. Guidance is also lean with moisture depth and there will be a fair amount of low level dry air to overcome to see measurable snow. Latest guidance does suggest a light dusting up to an inch possible north of I-69.

The early Saturday period bears monitoring as boundary layer moisture pools ahead of an inbound cold front, but upper moisture begins to strip out. Model solutions offer tenuous presence or even loss of ice nuclei - so patchy freezing drizzle is not out of the question before the front passes through during the day. This potential is currently less than 20% for any location. Post-frontal dry air then brings decreasing potential for any precip during the evening. The Saturday front brings the next bout of cold air that extends the below-normal stretch into next week with highs in the 20s and lows in the teens/single digits Sunday and Monday. A northern stream wave will track through the northern Great Lakes on Sunday bringing the next opportunity for light snow. Any accumulations would likely be minor. At this stage moisture depth doesn't look to be a concern with this wave and snow should be the ptype.

High pressure easing directly over the Great Lakes offers benign but cold weather to start the week. The Tuesday and Wednesday period remains a focus for a series of waves to track overhead within the energetic northwest flow around the Hudson Bay upper low. Ensemble guidance continues to exhibit relatively high agreement for widespread snowfall, with early system strength and moisture progs suggestive of potential for several inches during this time period.

MARINE...

With the cold front now to our east, winds have flipped around to the northwest across the region ushering an arctic airmass across the waters. Observations behind the front over Lake Superior show what was expected thus far with gusts into the low 30 knot range with sporadic gusts to 35 knots. Winds will peak over the next few hours and then will start to decrease through the rest of the morning hours. Small Craft Advisories remain in effect for the Lake Huron shoreline for winds to 30 knots and increased wave heights. After weakening to around 20 knots early tonight, there will be another round of increased southwesterly winds on Friday ahead of the next system passing through Ontario with the cold front swinging through early Saturday. Another round of Small Craft Advisories for Saginaw Bay may be needed and a few gusts to 35 knot gales can't be ruled out over northern and central Lake Huron.

CLIMATE...

The record low max temps for Thursday, December 4th.

Detroit: 23 Degrees (Set in 1895) Flint: 23 Degrees (Set in 1935) Saginaw: 22 Degrees (Set in 1991)

The record low min temps for Friday, December 5th.

Detroit: 6 Degrees (Set in 1974) Flint: 6 Degrees (Set in 1991) Saginaw: 6 Degrees (Set in 1991)

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory until 4 PM EST this afternoon for LHZ421-422- 441>443.

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