Sunrise 6:16 AM   Sunset 8:36 PM Moonrise 3:34 AM   Moonset 3:33 PM

  Print   HELP   Reset   Save   Recall

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 042303 AFDDTX

Area Forecast Discussion National Weather Service Detroit/Pontiac MI 703 PM EDT Sat May 4 2024

KEY MESSAGES

- Scattered showers and possible non-severe thunderstorms this evening through Sunday morning.

- High pressure builds in latter half of Sunday through Monday bringing drier conditions and closer to average temperatures.

- Developing low pressure over the Midwest brings widespread shower and thunderstorm chances Tuesday into Wednesday.

AVIATION

Late afternoon and early evening peak instability is just enough for a blossoming of showers as southerly cloud layer flow reinforced moisture across the area. Within and outside of the showers, borderline MVFR/VFR ceiling is widespread across SE Mi along with a notable area of clear sky or scattered clouds over western Lower Mi.
A brief clearing trend along the SE Mi terminal corridor adds complexity to the forecast as open sky could lead to fog and/or low cloud development post sunset but with low predictability. Lower ceiling and visibility are supported by boundary layer moisture continuing to pool ahead of the expansive Midwest cold front. The issuance time position of the front extends from Lake Superior through the mid MS valley and into the southern Plains while supporting a broken line of thunderstorms along its length. The front maintains integrity while moving into Lower Mi after midnight while the storms weaken with the loss of daytime instability. The front then moves through SE Mi with some lingering showers while maintaining IFR ceiling late tonight and early Sunday. A standard daytime ceiling improvement occurs as cooler north wind gains traction Sunday afternoon.

For DTW/D21 Convection... Thunderstorms south of TOL at issuance time are slow moving and dependent on daytime instability. These stay south of DTW while a pop-up shower or storm remains possible over or near the terminal until sunset. Instability continues decreasing this evening as a cold front and line of storms enter western Lower Mi. These storms also weaken to a few stray showers as the front moves through the DTW area around sunrise Sunday.

DTW THRESHOLD PROBABILITIES...

* Low for thunderstorms tonight.

* High for ceiling 5000 feet or less tonight and Sunday.

PREV DISCUSSION
Issued at 241 PM EDT Sat May 4 2024

DISCUSSION...

Southeasterly lower level flow has developed this afternoon in response to a weak cold front gradually sagging into the western Great Lakes. This wind shift supports modest moisture advection from Ohio, where dewpoints are holding in the mid 60s, nudging local Td's into the low 60s late this afternoon-evening. Even with this extra moisture, both SB/MLCAPEs are expected to stay fairly meager, holding closer to 500 J/kg. Forecast soundings advertise an uncapped environment with weak column winds (<20kts thru 500mb) which supports scattered pop-up showers and perhaps a thunderstorm into early tonight as height falls move in from the west and a diffuse PV anomaly lifts NE over far northwestern Ohio. Surface cold front crosses the area Sunday morning offering another window for scattered showers, particularly along/north of I-69 owing to closer proximity to parent shortwave which offers slightly better upper support/forcing compared to locales further south.

Marginally cooler airmass fallows the frontal passage as 850mb temps drop to around 4-5C keeping highs Monday in the upper 60s to around 70 for most areas. Easterly flow beneath the surface high that will be centered over northern lower MI by this point keeps areas downwind of the lakes like Monroe and especially the Thumb cooler- upper 50s to lower 60s favored.

Upper ridging and associated surface high are shunted east by early Tuesday as a potent mid-upper wave ejects out of the Rockies into the northern Plains. A secondary surface low is progged to develop over the upper Midwest along the original, now stacked, low's triple point. This system lifts a warm front into southern lower MI over the course of Tuesday bringing the area's next appreciable chances for showers and thunderstorms. The attendant cold front quickly follows Tuesday night generating additional widespread showers and storms. Worth noting that longer range solutions suggest a ~40kt LLJ could work into the area from west MI setting up a higher shear environment with severe potential dependent on how much destabilization occurs once the warm sector fully expands of the area. SE MI resides on the edge of SPC's Day 4 15% severe weather outlook so will be something to keep on eye on as we get closer.

MARINE...

An elongated area of low pressure over Wisconsin/Illinois this afternoon tracks east into the central Great Lakes tonight, pulling a warm front north ahead of it. This will result in an increasing coverage of showers as well as modest southeasterly winds tonight.
There will be a slight chance of thunderstorms but severe weather is not expected. A cold front follows on Sunday morning with continued shower/t-storm chances and a shift to northwest wind of around 15 to 20 knots as conditions dry out for the afternoon. High pressure then builds in to bring quiet marine conditions for Monday and much of Tuesday. The next round of likely precip arrives late Tuesday as a warm front moves into the area. This marks the beginning of a more active period through the rest of the week with several disturbances working through.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.

toggle option: (graph/table)

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Detroit, MI,