Sunrise 6:28 AM   Sunset 8:33 PM Moonrise 12:52 AM   Moonset 9:17 AM

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LCZ423 320 Am Edt Fri Apr 19 2024
.strong Thunderstorms approaching the waters - .
the areas affected include - . Detroit river - . Michigan waters of lake erie from detroit river to north cape mi - .
at 320 am edt, doppler radar indicated strong Thunderstorms, capable of producing winds up to 30 knots. These Thunderstorms were located along a line extending from 6 nm northwest of bolles harbor of refuge to 9 nm south of north cape, moving northeast at 40 knots.
strong Thunderstorms will be near - . Monroe harbor, bolles harbor of refuge, north cape, luna pier, and detroit beach around 325 am edt. Stony point and woodland beach around 330 am edt. Estral beach and gibraltar around 340 am edt. Lake erie metropark harbor and detroit river light around 345 am edt. Elizabeth park marina around 350 am edt.
other locations impacted by strong Thunderstorms include woodland beach, stony point, gibraltar, estral beach, and detroit beach.
precautionary/preparedness actions - .
mariners can expect gusty winds up to 30 knots, locally higher waves, and lightning strikes. Boaters should seek safe harbor immediately until these storms pass.
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lat - .lon 4173 8345 4173 8350 4180 8350 4195 8337 4197 8328 4217 8321 4219 8319 4218 8313 4212 8312 4203 8315 4196 8311 4180 8333 4172 8341 4172 8347

LCZ400
No data

FXUS63 KDTX 291734 AFDDTX

Area Forecast Discussion National Weather Service Detroit/Pontiac MI 134 PM EDT Mon Apr 29 2024

KEY MESSAGES

- Potential exists for showers and thunderstorms to develop through the evening. There is a marginal risk for storms to become severe during this time. Damaging wind gusts will be the main threat.

- Dry and slightly cooler Tuesday.

- Well above normal temperatures remain through the week.

AVIATION

Frontal boundary moves through southern Michigan this afternoon bringing chances for thunderstorms to all TAF sites this afternoon.
VFR conditions are expected outside the storms, with MVFR conditions or lower possible as storms move overhead. Showers have the potential to fill in behind the initial band of storms, but confidence remains low on what the extent or precise timing on those showers will be. Wherever these showers appear will have chances to drop to MVFR conditions, with the most likely sites being KDTW and KDET. Westerly flow will take over after the passage of a cold front early Tuesday morning. Some light fog is expected before sunrise, giving way to a 5000 foot cloud deck that will be present through the day Tuesday.

For DTW/D21 Convection...A scattered to broken line of showers and thunderstorms moves overhead between 19-22Z this afternoon. Behind this line further showers are expected to develop and impact the area between 0-4Z Tuesday. Although unlikely, there is still a possibility of thunder with these secondary showers.

DTW THRESHOLD PROBABILITIES...

* Moderate in thunderstorms this afternoon, then low this evening.

* High in ceilings at or below 5000 feet this afternoon, moderate this evening into early Tuesday morning.

PREV DISCUSSION
Issued at 937 AM EDT Mon Apr 29 2024

UPDATE...

Linear band of rain containing isolated thunderstorms easing into western lower Michigan late this morning. This nocturnal remnant corridor of saturation maintained along the nose of persistent 40+ knot 850 mb flow and focused within an east- northeastward propagating pre-frontal trough. This moist axis on pace to encounter a gradually destabilizing low level environment across the local area downstream, particularly southeast of a Howell to Bad Axe line as periods of greater insolation fuel steeper low level lapse rates within the modulating warm sector. A frontal zone currently anchored invof of the I-69 corridor will drift northward with time. Projected pace of this movement relative to the inbound precip band suggests the Saginaw valley will maintain a higher degree of stability. To the east, the existence of the boundary actually lends increased probability for backed low level flow to exist as the thumb continues to destabilize. With the underlying bulk shear magnitude sufficient to offer greater organization, marginal severe risk in play should instability prove adequate to generate and sustain meaningful updrafts. In addition to a standard stronger wind gust threat across the outlooked area, will continue to monitor the potential for updrafts to rotate as stronger cells engage the boundary/backed flow still lingering over the thumb region. Main window for activity from mid afternoon into the early evening /18z-23z/.

PREV DISCUSSION...
Issued at 404 AM EDT Mon Apr 29 2024

DISCUSSION...

West to east stationary boundary resides across the M-59 corridor this morning along with a very moist airmass. Dewpoints across much of southeast Michigan are into the 50s. North of this boundary are much cooler temperatures, which is supporting areas of patchy fog along and north of the I-69 corridor. Flow should be just strong enough to limit dense fog development with the isolated lower visibility in the half mile to three quarter mile range. A few isolated to scattered showers have moved northeast across the forecast area and have cleared to the north at press time.

Southeast Michigan should remain mostly rain shower free through the morning with the exception of a few scattered showers streaming across the Tri-Cities. To the west will be a nearly stacked low pressure system lifting across the western Great Lakes states and eventually into Ontario by tomorrow morning. Downstream will be increasing south-southwest flow starting to pick up around 12Z with gusts to 20-25 knots during the afternoon. Winds will drive the stalled boundary northward before the morning ends, which will also help improve visibilities after sunrise. Greater large scale ascent and height falls arrive today ahead of an advancing cold front. The lead wave of activity ahead of the cold front associated with a developing surface wave moving our of Illinois will move through mainly between 12 pm to 5 pm. The favorable diurnal timing will allow for the very moist airmass to destabilize helped by some breaks in clouds ahead of activity. MLCAPE up 250-500 J/kg looks achievable with the RAP offering MLCAPEs approaching 800 J/kg. The 30-40 knot 850 mb LLJ will be well positioned over southeast Michigan during the afternoon yielding 0-6 km bulk shear values to 35-45 knots. This environment would support at least some potential for isolated thunderstorms approaching severe levels. One of the limiting factors for robust convection today will be the meager mid level lapse rates at around 5.5 C/km. One area of interest to keep an eye on during the afternoon will be across the Tri-Cities and northern Thumb if the frontal boundary hangs around here. This would lead to a more southeasterly surface wind increasing low level shear as activity arrives and could lead to better thunderstorm organization for a 2-4 hour period.

Will maintain PoPs through the evening and overnight period as the main cold front moves through supporting mainly scattered showers.
Dry air is eventually ushered in under west winds bringing an end to precipitation shortly before 8 am tomorrow morning across eastern portions of the CWA The cooler airmass for Tuesday will yield daytime highs in the upper 60s to low 70s aside from some cooler spots along the Thumb lakeshores. Mostly clear skies will help temperatures fall into the 40s for tonight.

Some uncertainty in the mid-week, but the outgoing forecast is currently dry for Wednesday as a broad trough gets hung up over the northern US Rockies and northern plains. The northern jet turns more poleward and bring upper level diffluence over the region as deep south-southwest flow ushers in higher moisture back into Michigan.
This brings the next appreciable chance for precipitation in the Thursday to Friday time frame. High confidence exists in the mid to late week for above normal temperatures with daytime highs generally in the 70s and overnight lows in the 50s.

MARINE...

A low pressure system will continue to push northeast from southern Minnesota, settling over western Lake Superior by tonight. This will push the stalled frontal boundary across central Michigan north into the northern Great Lakes. Widespread rain showers and possibly a rumble of thunder is expected along and north of this front, across central and northern Lake Huron. Additionally, the position of the low will also reinforce northeast flow across the Great Lakes through tomorrow morning, with wind direction veering to the southeast by the afternoon. This will help maintain elevated wave heights across the outer Saginaw Bay to Harbor Beach, where Small Craft Advisories are in effect.

A very shallow mixing layer has developed over north to north- central Lake Huron, which will produce localized higher wind gusts now until 18Z. Gusts around 30 to 35 knots will be likely over the open waters from Mackinac Bridge to Sturgeon Point. Will preclude the issuance of a Gale Warning as confidence remains low whether gale potential will persist in any given three hour window, especially considering the stability of the marine layer. However, sporadic gusts to gales are likely through the morning and early afternoon hours. A short fused Gale Warning cannot be ruled out if early observational trends support it.

Otherwise, shower and storm potential will increase for all locations during the afternoon and evening, ahead of a cold front.
Any strong thunderstorm development will have the potential to produce isolated gusts to or above 30 knots.

HYDROLOGY...

Scattered showers and thunderstorms ahead of and along a cold front today. Additional rainfall amounts averaging a quarter inch to a half inch is expected today. The higher isolated totals up to a half inch or slightly more will be reserved for any more organized thunderstorms and favored more towards the Tri-Cities and Thumb region. No major flood concerns are expected through today.
Precipitation will come to an end by around 8 am tomorrow.

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

Dense Fog Advisory until 2 PM EDT this afternoon for LHZ441>443- 462>464.

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

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