Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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665 FXUS63 KDTX 151700 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 100 PM EDT Sun Sep 15 2024 .KEY MESSAGES... - Seasonably warm and dry conditions prevail through mid-week with patchy morning fog Sunday through Tuesday. - Spotty light rain becomes possible Wednesday. && .AVIATION... Large-scale pattern remains locked-in again through the TAF period based on sprawling surface high pressure centered near Cape Cod. This provides generally clear skies and light southeasterly winds AOB 10 knots through the daylight hours. Wildfire smoke continues to stream in aloft with negligible impact on overall sky fraction. Persistence forecast warrants continuation of MVFR fog restrictions Monday morning from PTK south with lower potential for brief visibility drops to IFR. Based on previous observational trends, IFR development is more likely for YIP and/or DET. For DTW/D21 Convection...Thunderstorms are not forecast this week. DTW THRESHOLD PROBABILITIES... * None. && .PREV DISCUSSION... Issued at 353 AM EDT Sun Sep 15 2024 DISCUSSION... An outstanding mid September weekend wraps up with another day of dry weather, warm temperatures, and moderate humidity. Full sun filtered through high altitude forest fire smoke is the only minor flaw of note but does little to prevent another round of high temperatures in the mid 80s across SE Mi. These conditions are a continuation of remarkably good weather in the Great Lakes provided by a highly amplified and stable large scale pattern across North America. The mid level ridge portion of a mature rex block generally holds from the Great Lakes into the New England states today through Tuesday while the low pressure portion consists of inland Francine remnants combined with a mid Atlantic hybrid tropical circulation. This mid Atlantic system is the predictability challenge in the forecast for the next several days and represents potentially our next chance of rain by mid week. The westward trend in the mid level system track continues with some notable timing spread among the new 00Z regional and global deterministic models. NAM/GFS timing is considerably faster/farther west compared to the ECMWF and Canadian possibly due to upstream height falls across the central Rockies drawing the system westward more quickly. The GFS is considerably faster than its ensemble mean and an incremental POP increase might be best until some timing clarification materializes in later model cycles. For now, dNBM/dt reflects the general trend with a reasonable upward nudge to about a 20 POP in SE Mi late Tuesday night through Wednesday. Extended global models indicate a tendency for northern stream short wave energy lifting from the central Rockies into central Canada during the late week. This is shown to build a new 500 mb mid level ridge over northern Ontario to reinforce the eastern States rex block. This could result in the closed low component of the block lingering near the Great Lakes resulting in relatively unsettled conditions Thursday and Friday. MARINE... High pressure continues to dominate conditions across the central Great Lakes through at least the first half of next week. Southerly flow develops today and persists into the first part of the work week, though it will hold on the lighter side (aob 15kts). && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....KGK DISCUSSION...BT MARINE.......KDK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.