660 FXUS63 KDTX 051907 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 307 PM EDT Mon Oct 5 2020 .DISCUSSION... Warmer air will shift into the area with increasing west/southwest flow in the wake of a passing surface ridge tonight into Tuesday with only a slight intrusion of cooler air late in the day as a weak shortwave passes quickly north of the area. This will lead to both a milder night tonight with lows in the lower to mid 40s and warmer day on Tuesday with highs reaching the mid to upper 60s. The only mention of rain showers in the forecast will come in the Tuesday night or early Wednesday period as another stronger vort max is sheared eastward into the northern Great Lakes. Any activity looks to remain over far northern portions of the forecast area. The pressure gradient in advance of the surface reflection of this wave will maintain steady southwest flow Tuesday which, along with an increase in cloud cover, will lead to mild temperatures will lows in the lower 50s for the most part. By starting the day on the mild side, expect highs to climb back into the mid 60s to lower 70s from north to south across the region on Wednesday before cooler air begins to settle back into the area during the afternoon/evening as the aforementioned disturbance passes the area. Cooler conditions will hold into Thursday as high pressure builds into the area. However, the area will be on the southwestern periphery of the coldest shot of air behind the wave so highs will still climb into the upper 50s to lower 60s. Temperatures will then warm from Friday into Saturday as strong warm air advection ensues on southwest flow from Friday into Friday night. Expect highs in the mid to upper 60s to 70ish Friday and 70s in most locations on Saturday before a backdoor cold front begins to settle south into the area late in the day. While this will blunt the warm conditions to some degree, the coldest core of air remains well north northeast of the area so highs will still reach the 60s Sunday and again Monday with some 70 degree readings still quite possible over far southern parts of the forecast area. && .MARINE... A warm front will move north across the Great Lakes later this afternoon into the evening and with it will come stronger southwest flow. This stronger wind field in conjunction with a strengthening pressure gradient will ramp up wind speeds tonight which has resulted in the issuance of Small Craft Advisories for all nearshore zones, with the exception of western Lake Erie. Small Crafts have been issued mainly for wind concerns, as gusts are expected to ramp up to around 25 knots when the advisory starts. The strongest winds and more elevated wave action is expected across central Lake Huron, where gusts around 30 knots are expected. Some brief gusts to gales will also be possible. The pressure gradient will relax by Tuesday afternoon, but lighter wind speeds will be short-lived as a cold front and strong wind field move over the Great Lakes on Wednesday. Another round of Small Craft Advisories will likely be needed on Wednesday, and there is a high likelihood of a Gale Watch being issued for portions of Lake Huron prior to the event. && .PREV DISCUSSION... Issued at 145 PM EDT Mon Oct 5 2020 AVIATION... VFR conditions are expected this cycle as high pressure influence spills across the terminals. A developing cumulus field in the wake of morning low-cloudiness will generally be confined to the southern airfields, and given the FEW-SCT coverage designation, impact on aviation operations should be limited. Winds remain fairly light this afternoon and evening, holding in the 5-10 knot range from the S/SW. Winds trend upward Tuesday morning with gusts to around 20 knots as lower troposphere winds associated with a large trough aloft push through a dry cold front with continued VFR skies. For DTW...VFR the rest of today with winds increasing late tonight. SW gusts to 20 knots are possible on Tuesday with dry conditions. There may be an occasional high-end MVFR 3 kft ceiling Tuesday afternoon, but clouds will generally remain SCT or less in coverage. DTW THRESHOLD PROBABILITIES... * Low for ceiling at or below 5000 ft this afternoon. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Small Craft Advisory from 8 PM this evening to noon EDT Tuesday for LHZ421-422-441>443. Lake St Clair...Small Craft Advisory from 2 AM to noon EDT Tuesday for LCZ460. Michigan waters of Lake Erie...NONE. && $$ DISCUSSION...DG MARINE.......AM AVIATION.....KK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.