Sunrise 6:19 AM   Sunset 8:33 PM Moonrise 2:45 AM   Moonset 12:58 PM

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LCZ422 /o.exp.kdtx.ma.w.0003.000000t0000z-240417t2115z/ 505 Pm Edt Wed Apr 17 2024
.the special marine warning will expire at 515 pm edt - .
the affected areas were - . Lake st. Clair open lake (u.s. Portion) - . St. Clair river - .
the Thunderstorms have moved out of the area and no longer pose a significant threat to boaters.
a severe Thunderstorm watch remains in effect until 700 pm edt for southeastern michigan - .the adjacent waters of lake huron - .and the adjacent waters of lake st. Clair.
&&
lat - .lon 4289 8247 4280 8248 4276 8247 4261 8252 4255 8259 4256 8264 4246 8274 4259 8285 4266 8285 4272 8269 4270 8261 4265 8259 4264 8256 4276 8251 4289 8252 4301 8247 4302 8243 4298 8241 time - .mot - .loc 2105z 242deg 52kt 4323 8228 4292 8200 4269 8178

LCZ400
No data

FXUS63 KDTX 021946 AFDDTX

Area Forecast Discussion National Weather Service Detroit/Pontiac MI 346 PM EDT Thu May 2 2024

KEY MESSAGES

- There is a chance of showers and a few thunderstorms late tonight through Friday morning and again Friday afternoon as a cold front tracks across SE Michigan.

- Severe weather is not expected on Friday, although thunderstorms will be capable of heavy downpours, lightning, and isolated wind gusts to 40 mph. Storm motion will be southwest to northeast at 40 mph.

- High pressure fills in briefly on Saturday offering drier weather ahead of the next cold front that tracks through SE Michigan early Sunday morning.

- Seasonably warm temperatures expected through early next week with high temperatures in the 70s and lows in the 50s.

DISCUSSION

Another seasonably warm day has ensued across SE MI today, with temperatures for most inland locations peaking in the low 70s.
Elevated portions of the inbound warm front already starting to bring a band of convectively enhanced cloud cover into western lower MI at issuance, with expanding cloud cover expected through the evening. Very dry low levels, denoted by T/Td spreads of 20+ degrees, confirm that present radar echoes are just virga so will hold on to a dry forecast through the evening.

In typical warm advection fashion, precipitation chances increase with the arrival of the low level moisture axis late tonight.
Leading wave of low level moisture advection is tied to a convectively enhanced shortwave that lifts into lower MI after 06z (2am local) tonight, but initial attempts at low level saturation will struggle to overcome the dry resident airmass (12z DTX RAOB observed PWAT of 0.62" this morning). Can already see this struggle ongoing over northern IN/OH (per GOES-16 visible imagery) where a sharp gradient in the cumulus field is observed. Nonetheless, broad isentropic ascent and weak instability aloft (HRRR ensemble mean MUCAPE up to 500 J/kg) should assist the saturation process to allow increasing coverage of showers and potentially a few thunderstorms Friday morning. Best coverage will likely be across the Tri Cities, as the SW-NE orientation of an incoming cold front pushes a narrow corridor of moisture into SW lower Michigan and the northwest portions of the cwa during the morning hours. The cold front will then drift eastward throughout the day, becoming a renewed albeit weakening forcing mechanism for surface-based convection to develop Friday afternoon. Even in the absence of showers/storms, the deep column moisture will support a cloudy day across lower MI.

Did reduce forecast high temperatures on Friday by several degrees, owing to the increased potential for cloud cover and shower activity to interfere with diurnal heating. Still, 850mb temperatures around 10-12 C are indicative of a seasonably warm airmass which will still support daytime highs Friday in the low 70s. These cooler boundary layer conditions, combined with mid level lapse rates below 6 C/km will keep MLCAPE prospects around 500 J/kg. With the front extending well ahead of the more dynamic parent system (over MN/WI), there will be a notable absence of upper jet forcing and mid/upper level flow. So while thunderstorms may develop along the fropa Friday afternoon, environmental conditions will not be favorable for storm organization/longevity, so severe weather is not expected.

The front will have little impact on thermal profiles heading into the weekend, as the boundary will be stretched and eventually wash out as its parent system stalls again, this time over Hudson Bay.
This results in an extended period of above normal temperatures, with highs comfortably in the 70s and lows in the 50s through early next week. Mid-level ridging pattern generally holds steady through early week, with dry weather expected Saturday ahead of another cold front Sunday morning. Strongest signal for a pattern shift holds off until middle of next week when a strong Pacific low tracks across CONUS, bringing the next meaningful window for precipitation.

MARINE

High pressure over Lake Huron is resulting in light and variable flow this afternoon, but an approaching warm front to the southwest will help flow to become more easterly, but remain below 20 knots, for tonight. A low pressure system will then track through the northern Great Lakes on Friday pulling the warm front up through the region early in the day. This will allow winds to flip around to the south-southwest which will bring in a warmer airmass, helping to keep gusts down. Scattered showers and thunderstorms will occur Friday morning across the area on the warm front with continued activity later in the day along the cold front. Shower chances carry through Friday night. High pressure brings quieter weather on Saturday with another cold front coming on Sunday.

PREV DISCUSSION
Issued at 208 PM EDT Thu May 2 2024

AVIATION...

VFR conditions will persist throughout the afternoon and evening hours with an amplifying ridge overhead and anticyclonic trajectories. Any lake breeze response will remain muted with a prevailing southeast wind direction this afternoon already in advance of the mesoscale forcing. A deep potential vorticity lobe will pivot across northern Minnesota this evening and tonight driving a narrowing axis meridional moisture transport across Southeast Michigan Friday. Precipitation chances begin to increase after 09Z Friday as southern stream/mississippi River Valley moisture does lift northward and streamlines immediately in advance of the northern tier trough. Two specific time windows of concern at the Detroit terminals, a quick chance for elevated shower activity between 09-11Z and the potential for some shower/tstorms developing along a weak cold front Friday afternoon. Confidence in coverage and occurrence is lower Friday afternoon and did account by a Prob30.

For DTW/D21 Convection...Shower activity is expected to lift northward out of northern Ohio between 09-11Z Friday with a low potential for thunderstorms. Additional shower activity with thunderstorms will develop over portions of Southeast Michigan after 19Z. Low confidence in occurrence at Metro as activity could remain north and west. Strong to severe thunderstorms are not anticipated Friday.

DTW THRESHOLD PROBABILITIES...

* Low for thunderstorms tonight and Friday



DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.

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