FXUS63 KDTX 270350 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1150 PM EDT Sun Oct 26 2025 .KEY MESSAGES... - Seasonably cool and dry weather continues for the rest of the weekend and early next week. - Increasing rain chances through the late week period. && .AVIATION... Surface high pressure will continue to expand into Southeast Michigan from Ontario tonight. Anticyclonic flow trajectories will support isentropic downglide and active subsidence in the 3.0 to 15.0 kft agl layer. Prevailing VFR conditions are anticipated throughout much of the area. There is a potential for Lake Erie moisture to advect into the Detroit terminals around daybreak Monday morning. Uncertainty exists in BKN ceilings below 5.0 kft agl but given satellite trends downwind of the Great Lakes this evening decided to introduce a TEMPO of BKN025 ceiling. For DTW/D21 Convection...No thunderstorm activity this TAF period. DTW THRESHOLD PROBABILITIES... * Low for cig aob 5000 feet Monday morning. && .PREV DISCUSSION... Issued at 300 PM EDT Sun Oct 26 2025 DISCUSSION... Western periphery of a strong 1033mb high pressure system remains the prominent synoptic feature today which has yielded mostly clear skies. Exceptions are the ongoing cu field over the Thumb and Tri- Cities, sustained by east flow lake moisture advection. Despite weak caa, daytime temperatures have warmed to near-normal values in the mid 50s, aided from the larger scale dynamic subsidence. Increasing stability and continued push of dry air advection, noted from a strengthening inversion between 800-700mb and large dew point depressions in the low levels, will ensure clear conditions overnight, allowing temperatures to drop into the 30s. Temperatures below the freezing mark are likely within the Irish Hills and Tri- Cities, away from the influence of Lake Huron and Saginaw Bay. Patchy frost is possible but the antecedent dry surface conditions preclude any stronger wording for frost potential. A persistence forecast is in play for tomorrow with temperatures returning seasonal values under mostly clear skies. Overall longwave pattern will promote a window for increased stability through the early week period. High pressure will stagnate across Ontario and Quebec while an upper-level low travels from the southern Plains into the continental southeast. Concurrently, an upper-level trough across the northwest and northern Plains will amplify which in turn will sustained upper-level ridging across the Great Lakes area. The amplified trough is expected to pinch off into a closed low across the central and southern Plains before propagating into the Ohio Valley, a path that will bring a robust area of PVA and mid-level height falls into the region starting Late Wednesday. This will bring increasing rain chances starting late Wednesday, with building probabilities into Thursday given the boost in isentropic ascent. Pending the final position of the low, PoP chances could through Halloween, along a deformation axis along the northwest side of the low center. This looks increasingly likely with long duration PoP values hovering between 50-60%. Muted changes to the overall thermal profile brings a stretch of highs in the 50s and lows in the mid to upper 30s through the forecast period. MARINE... The central great lakes will remain positioned between high pressure centered over Quebec and low pressure lifting across the midwest during the early week period. This will maintain an extended period of easterly flow during this time. Sustained winds of generally 10 to 20 knots, with intermittent gustiness to 25 knots at times. The prevailing onshore flow will bring increasing wave action along the nearshore waters. Small craft advisory conditions for wave heights expected starting Monday evening and likely lasting into Wednesday. No rain is in the forecast through at least Tuesday. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...Small Craft Advisory from 8 PM Monday to 4 PM EDT Wednesday for LHZ421-441>443. Lake St Clair...None. Michigan waters of Lake Erie...Small Craft Advisory from 8 PM Monday to 4 PM EDT Tuesday for LEZ444. && $$ AVIATION.....CB DISCUSSION...AM MARINE.......MR You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.