textproduct: Detroit/Pontiac

KEY MESSAGES

- Stretch of colder conditions will exist through Tuesday with temperatures remaining below normal during this time.

- Potential for a mix of rain and snow exists this afternoon into tonight. Brief higher intensity bursts of snow showers will be possible, with a dusting of accumulation on grassy surfaces in some areas.

- The next good chance for rain will be Thursday into Friday.

DTW THRESHOLD PROBABILITIES

* Moderate for ceilings at or below 5000 ft today. * Moderate for ptype to be rain/snow mix this afternoon.

PREV DISCUSSION

Issued at 312 AM EDT Mon Apr 6 2026

DISCUSSION...

General mid level troughing to remain a fixture throughout the early week period. Latest water vapor analysis highlights two distinct, minor perturbations propagating east-southeast into the broader lower height anomaly. The first feature on pace to translate across the local area this morning. Latest observational and radar trends solidify current expectation for a focused, weak area of ascent to provide a supportive environment for some pockets of very light precipitation production thru mid morning. Subtle window here for brief, modest warm air advection before another meaningful period of cold air advection emerges this afternoon and evening as a secondary, more potent shortwave shears through. Daytime heating beneath a cold mid-level core at 500-700 mb will yield very steep lapse rates across a deep layer. This environment will support a scattered to numerous coverage of showers. Given lower wet-bulb zero heights and weak low level instability, some heavier convective bursts are plausible leading to brief instances of graupel or higher intensity snow showers, even as temps peak in the 40s. Late day gustiness to northwest wind into the 30 mph range.

Strongest period of cold air advection occurs tonight. This process likely fuels additional light snow shower production, with enhancement offered by some degree of convergence with the cold frontal passage and a trailing surface trough migrating off lake Huron. Highest probability will exist across the thumb. Minor localized grassy accumulation at less than half an inch expected given limitation in duration. Higher magnitude thermal advection will lead to 850 mb temps below -12c by Tuesday morning. Lows in the low to mid 20s. Coldest conditions of the week then noted throughout Tuesday with the low level thermal trough in residence. Some lingering stratus and possible flurries early in the day, before increasing influence of encroaching high pressure offers greater deep layer drying and stability. Highs Tuesday mainly in the 30s.

Notable shift in the larger scale pattern for the latter half of the week, as the mean flow reverts back to Pacific origin. Modest height rises will initiate a respectable warming trend starting Wednesday, moderating temperatures back to near normal. Warm frontal boundary will lift through sometime late Wednesday with little fanfare given limited moisture quality, effectively establishing a meaningful window for deeper warm air advection Wednesday night into Thursday. This occurs as a dynamic mid level wave ejecting across the US/Canadian border drags a slow-moving cold front into lower Michigan. Backed by a greater influx of moisture under deeper pre- frontal southwest flow, this will lead to a good chance of rain. Eastward pace of the frontal boundary remains in question at this stage as the boundary becomes increasingly parallel to the mean flow. Outgoing forecast maintains a broader, more prolonged opportunity for rain lasting into Friday. Further forecast revision likely this period.

MARINE...

A weakening of the pressure gradient occurs this morning as a clipper system tracks across the region. This system will excite another period of cold advection late today through tonight and into early Tuesday, with north to northwest wind increasing to the 15 to 25 kt range with brief gusts to 30 kt over Lake Huron. Small Craft Advisories are in effect for the Lake Huron nearshore waters where waves will build over 4 feet across the southern basin. High pressure builds in briefly on Tuesday causing wind and waves to subside. Flow then strengthens out of the south on Wednesday as the next low pressure system tracks into the upper Midwest. This system will send a slow-moving cold front across the Great Lakes Thursday and Friday.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None. Lake Huron...Small Craft Advisory from 4 PM this afternoon to 10 AM EDT Tuesday for LHZ421.

Small Craft Advisory from 4 PM this afternoon to 4 AM EDT Tuesday for LHZ422.

Small Craft Advisory from 8 PM this evening to 4 PM EDT Tuesday for LHZ441>443.

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