Sunrise 6:26 AM   Sunset 8:27 PM Moonrise 11:53 PM   Moonset 7:16 AM

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LHZ443 Port Sanilac To Port Huron Mi- 415 Am Edt Sat Apr 27 2024
.small craft advisory in effect until 4 pm edt this afternoon - .
Today - South winds 15 to 20 knots. Mostly cloudy. Light showers likely and a chance of Thunderstorms in the morning, then a chance of showers and a slight chance of Thunderstorms in the afternoon. Waves 3 to 5 feet. Waves occasionally around 6 feet. Tonight - South winds 15 to 20 knots becoming southwest 10 to 15 knots after midnight. Partly cloudy with a slight chance of showers and Thunderstorms in the evening, then mostly cloudy with a chance of showers and a slight chance of Thunderstorms after midnight. Waves 2 to 4 feet subsiding to 1 to 3 feet in the late evening and overnight. Sunday - Southwest winds 10 to 15 knots veering to the northwest early in the afternoon. Mostly cloudy. A chance of showers and Thunderstorms in the morning, then a chance of showers in the afternoon. Waves 2 feet or less. Sunday night - North winds 10 to 15 knots becoming northeast 5 to 10 knots in the late evening and early morning, then becoming southeast 10 to 15 knots after midnight. Mostly cloudy with a chance of showers. Waves 2 feet or less.
see lake huron open lake forecast for days 3 through 5.

LHZ400
No data

FXUS63 KDTX 270800 AFDDTX

Area Forecast Discussion National Weather Service Detroit/Pontiac MI 400 AM EDT Sat Apr 27 2024

KEY MESSAGES

- Scattered showers and storms develop this morning, then some additional activity is possible tonight, mainly for the Tri-Cities area.

- Southwest winds gust to 35 mph this afternoon.

- Additional showers and storms are possible Sunday and Monday with above normal temperatures before a cold front arrives on Tuesday.

DISCUSSION

Surface low pressure (993 mb) affecting morning shower development across Southeast Michigan accelerates northeastward from central Minnesota to The Keweenaw Peninsula today as the governing wave aloft opens up, interacting with a northern stream shortwave over Ontario. This adjustment induces further constriction of the surface pressure gradient as a 1034 mb surface ridge builds south across the Mid-Atlantic. Local flow veers from SE to SW today with prevailing speeds in excess of 15 knots. Low-level wind profiles reveal 50+ knot flow near the 5 kft AGL level, but given the warm advection regime, mixing depths remain quite shallow for most of the diurnal period. Still, with 25+ knot winds down to 500 ft AGL, gusts will generally range between 25 and 35 mph by late morning.

Regarding precipitation processes, the initial band of showers tied to isentropic ascent have moved off to the northeast while scattered activity begins to develop with inbound frontogenesis. These showers also benefit from substantial dynamic support as a region of divergence moves in aloft while the main LLJ axis situates over southern Lower Michigan. Potential exists for updraft overachievement with UVVs capable of some lightning generation in spite of limited instability. Opted to maintain current Slight/Chance Thunder wording with revised PoPs. Given the barrage of ThetaE convergence and CVA, CAM depiction varies in specifics, but most of the morning convective activity should conclude by 16Z while some lingering showers persist near the shoreline communities until 18Z. Confidence continues to rise in a mainly dry afternoon forecast as the western extend of the Atlantic anticyclone impinges on the region. This also promotes some thinning of the cloud deck and a late day boost to temperatures. Fully entrenched within the warm sector marked by 850 mb temps of 12C to 13C, should easily break into the mid (if not upper) 70s this afternoon, roughly 15F above normal.

The anomalous warmth paired with Gulf-augmented dewpoints approaching 60F this evening prime Lower Michigan for modest conditional instability. Main concern is the presence of a capping inversion around 6 kft that is represented in the NAMnest and GFS while the feature is less prevalent via the ARW and RAP.
Additionally, RH cross-sections highlight the impact of the veered mid-level flow which effectively dries out the column above the inversion. Lift mechanism(s) might be non-existent during this timeframe as the system's cold front remains stalled over Western Michigan. The boundary won't release until later in the evening as an upstream wave ejects out of the synoptic subtropical jet from the Desert Southwest. Given this lagged frontal progression, perhaps as late as midnight, the main threat for both broader coverage of thunderstorms and any strong to severe activity is largely reserved for the Tri-Cities area where MUCAPEs peak with 35-40 knots of EBS.
SPC continues to advertise a Marginal Risk for severe weather west of a line from Adrian to Bad Axe which should stay quite isolated in nature should storms materialize.

The front should be in the process of washing out by Sunday morning and taking position as a bisecting stationary boundary. Not much in the way of synoptic adjustments as the secondary shortwave takes a slightly more westerly trajectory through the Upper Midwest than today's. Persistent ThetaE advection and additional warming capitalize on the surface convergence axis for addition showers/storms while the better forcing aloft holds off to the northwest. Very warm conditions expected for areas south of the front with highs breaking 80F across the southern four counties.
Additional rounds of showers and/or storms possible Sunday night.

Nuisance forecast extends into Monday with additional periods of convective activity as the warm sector resides over the region, but the VortMax from the secondary wave remains well off to the west.
Persistent moisture transport and confluent low-level flow maintain unstable conditions with opportunities for both elevated and surface based convection. A cold front arrives Monday night with increasingly uniform westerly flow through the column. A cooler and drier forecast stays through Wednesday morning, dependent on the status of an extensive cold front draped from Manitoba to Texas should wash out over the Great Lakes. Active pattern returns through the latter half of the week with at least two speed maxes work through the northern tier of the Lower 48 with revitalized warm advection.

MARINE

Strong low pressure moves across Lake Superior on today. Wind veer southerly today with gusts touching gale force this morning before gradually weakening through the day as much warmer air moves into the region to stabilize flow over the cold lake water. The warm air also fuels thunderstorm potential through tonight, and possibly even into Sunday as the associated cold front stalls over the region. The front awaits yet another low pressure system moving in from the Plains Sunday into Monday.

CLIMATE

Here are the record high temperatures for April 28th:

April 28th: Detroit 84 (set in 1986)
Flint 85 (set in 1990)
Saginaw/Tri-Cities 85 (set in 1990)

PREV DISCUSSION
Issued at 1143 PM EDT Fri Apr 26 2024

AVIATION...

Several inbound short wave impulses along with increasing low level southwest flow along an advancing warm front will drive another round of showers across Se Mi late tonight into Saturday morning.
This will also be accompanied by weak elevated instability, enough to suggest a 20 to 30 percent chance of a thunderstorm embedded within the broader region of showers. Moistening in the low levels will also support high probabilities for MVFR based ceilings. The warm front will lift northeast of the terminals late Sat morning as associated surface low pressure approaches western Upper Michigan.
This will drive the warm sector into Se Mi. Deepening of the daytime mixed layer and the strengthening SSW wind fields will push wind gusts up to or over 25 knots at times during the afternoon Saturday.
Late day convection on Saturday/Saturday evening is forecast to initiate across northern and central Lower Mi.

For DTW/D21 Convection...Numerous showers are expected to move into and redevelop across the airspace overnight and last into late Saturday morning. Recent model guidance remains lean on the amount of available instability, so only isolated thunderstorms are expected across the airspace, primarily between 09Z and 13Z.

DTW THRESHOLD PROBABILITIES...

* Low in thunderstorms tonight into early Saturday morning.

* High in ceilings aob 5000 feet tonight into Saturday afternoon.



DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...Small Craft Advisory until 4 PM EDT this afternoon for LHZ421-422- 441>443.

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

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