561 FXUS63 KDTX 062308 AFDDTXArea Forecast Discussion National Weather Service Detroit/Pontiac MI 708 PM EDT Mon Oct 6 2025
.KEY MESSAGES...
- Showers and scattered thunderstorms tonight and Monday morning, lingering into the afternoon toward metro Detroit.
- Much cooler conditions Tuesday through the end of the week.
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.AVIATION...
A cold front moving NW to SE across Lower Mi is the primary forecast focus for tonight and Tuesday. It brings increasing coverage of showers and scattered thunderstorms to the SE Mi terminal corridor this evening, while a few additional showers graze the DTW area, peaking in coverage/intensity all areas after midnight into Tuesday morning as the front moves overhead. The front also brings solid coverage of MVFR ceiling with a greater IFR component also toward sunrise while at the same time improving quickly from MBS southward after sunrise. MVFR ceiling and post frontal showers linger longer toward DTW, however a return to VFR is projected at all locations by 21Z Tuesday afternoon.
For DTW/D21 Convection... There is a low chance (30%) for thunderstorms to impact the DTW airspace late tonight and Tuesday morning.
DTW THRESHOLD PROBABILITIES...
* High for ceiling 5000 ft or less late tonight and Tuesday morning.
* Low for thunderstorms late tonight and Tuesday morning between 10z and 14z.
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.PREV DISCUSSION... Issued at 301 PM EDT Mon Oct 6 2025
DISCUSSION...
Last day of the anomalously warmer temperatures is underway under brisk southwest flow which have propelled temperatures back into the 80s this afternoon. A stark change in temperatures will arrive by tomorrow after the passage of a cold front, which also brings shower and thunderstorm chances.
A strong shortwave impulse will round into western Ontario through the day today and will amplify the greater trough feature through the northern Plains, aiding in the continued progression of a strong cold front that now extends through northern lower Michigan. Slow progression of the front will continue through the morning hours tomorrow as deep-layer steering flow remains largely parallel to the boundary. As the front arrives within the vicinity of and over SE MI, numerous showers with embedded thunderstorms will move in, aided from the efficient deep transport of high theta-e moisture coupled with elevated instability.
Hi-res models continue to pick up on the potential for prefrontal development late tonight through Midnight favored across the Tri- Cities and Thumb. Unidirectional wind direction could promote some isl to sct pulse or linear segmented convection. Some pockets of localized gusty winds will be possible with this activity, but the overall elevated nature precludes any stronger wording of damaging gust potential. Frontal progression will then pick up through the mid to late morning hours as flow aloft veers, enhancing the frontogenetic response, especially across the Tri-Cities and Thumb. The cold front and subsequent rain chances clear the cwa entirely in the afternoon hours.
An anomalously strong surface high pressure system is then set to build into the area through the midweek period, with central SLP values expected to reach of exceed the 99.5th percentile of the climatological distribution for this time of year. The extreme strength is amplified by a synergistic dynamic setup. Specifically, the Great Lakes will be situated beneath the right exit region of the nnw-sse jet over Ontario which will maximize upper-level confluent flow. Coupled with cold air advection in the low levels through 850mb which increases density of the column, SLP increases and peaks by Thursday morning. The passage of the cold front and thermal trough brings stark temperature changes Tues-Thurs afternoon with highs in the low to mid 60s and lows 30s (Wed-Fri morning). The coolest night will likely be Thursday morning as lows drop into the low to mid 30s, which will bring frost and freeze concerns. Otherwise, this aforementioned setup brings dry weather and clear skies through the midweek period.
MARINE...
A cold front will continue to slowly track south through the Central Great Lakes this evening and tonight, with blossoming showers and embedded thunderstorms expected. Stronger thunderstorms will be capable of producing wind gusts of 35+ knots.
Post frontal cold air advection through tomorrow as 850 MB temps fall into the low single numbers to near zero. A period of wind gusts up to 30 knots is expected across northern Lake Huron Tuesday evening with the increased boundary layer before winds slowly diminish and veer north-northeast on Wednesday as expansive high pressure arrives. Despite winds diminishing, the northerly flow will lead to larger waves over the southern Lake Huron basin Tuesday evening into Wednesday, with small craft advisories needed during this time for the nearshore waters as the cold airmass leads to unstable low level profiles conducive to good wave growth with the long north-northeast fetch.
HYDROLOGY...
A cold front will bring numerous showers with embedded thunderstorms to SE MI late tonight through tomorrow morning. Basin averaged rainfall totals are expected to range between a quarter-inch to a half-inch of rainfall, with some localized higher amounts likely with any repeated shower or thunderstorm activity. The most likely location for repeated activity will reside along or north of I-69, through the Tri-Cities and Thumb, where totals closer to an inch or more will be possible. Given the antecedent dry conditions, localized flooding is not expected.
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.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from 10 PM Tuesday to 10 PM EDT Wednesday for LHZ421-441>443.
Small Craft Advisory from 10 PM Tuesday to 4 PM EDT Wednesday for LHZ422.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
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AVIATION.....BT DISCUSSION...AM MARINE.......SF HYDROLOGY....AM
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NWS DTX Office Area Forecast Discussion