Sunrise 6:41 AM   Sunset 8:22 PM Moonrise 4:18 PM   Moonset 4:28 AM

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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 200755 AFDDTX

Area Forecast Discussion National Weather Service Detroit/Pontiac MI 355 AM EDT Sat Apr 20 2024

KEY MESSAGES

- Brisk and mostly cloudy today followed by more sun and a temperature rebound on Sunday. Frost is possible tonight and Sunday night.

- Next chance of showers and thunderstorms arrives Tuesday.

DISCUSSION

Mid-level height falls are evident in regional water vapor imagery this morning as a lobe of PV is driven across the Great Lakes by a deepening closed low over Hudson Bay. This is sending a cold front across the region but with minimal moisture advection into the 0.30 inch PWAT environment sampled by the 00z DTX RAOB, the front is passing over largely precip-free save for some light flurries in the Thumb. It will however usher in just enough post-frontal boundary layer moisture to maintain a healthy stratocumulus field through much of the day. 850mb temps settle to near -8 C this afternoon which is below the 10th percentile per SPC sounding climatology, keeping high temps seasonably cool in the mid 40s to around 50.
Meanwhile, a stout pressure gradient holds over the region between the Canadian low and high pressure building into the Ohio and Tennessee Valleys, producing a breezy west wind at 20 to 25 mph. The end result will be a brisk and mostly cloudy April day with a wind chill in the lower to mid 40s.

The cold and dry air mass will stick around through tonight before a slight temperature rebound on Sunday. With our growing season off to an early start, frost/freeze concerns come into play with low temps likely to fall to the lower to mid 30s. Lots of clouds noted in upstream satellite imagery and plenty of variance among model solutions brings uncertainty in the degree of clearing that will occur tonight. Weak gradient wind will also be a factor that will likely prevent temps from completely cratering. Did consider a Frost Advisory with this package but ultimately decided to defer to the next shift when trends in clouds, winds, and low temps should become more apparent.

Another dry mid-level trough passes overhead Sunday morning, ushering out the coolest air and inducing a deep layer subsidence response through the rest of the day. This warms the column while maintaining mostly sunny skies to provide a boost in surface heating. This nets a meaningful temperature rebound to the mid to upper 50s. The breezy west wind will remain pervasive over the region for another day. This leads into another chilly period Sunday night with lows again flirting with the freezing mark. On Monday, an amplified 850mb ridge crests overhead, keeping conditions dry and opening the door for more meaningful warm advection to trend high temps up a few more degrees into the lower 60s.

Tuesday remains the target for our next round of showers and potential thunderstorms as there continues to be good agreement in model solutions showing a closed low over Manitoba ejecting ESE as an open shortwave. Developing southwest flow provides a steady moisture stream ahead of the attendant cold front, with LREF mean showing PWATs increasing to around 0.75 inches. This supports the 60- 70% PoPs provided by the NBM. The GEFS suite continues to advertise a stronger cold advective response behind this wave, driven by a seemingly over amplified Hudson Bay PV anomaly not represented in the ENS and GEPS ensembles. The mid-week temperature forecast continues to carry a good amount of uncertainty at this stage, but potential is there for sub freezing temperatures if the colder solution does play out.

MARINE

Upper level trough holds over the central Great Lakes this weekend maintaining the cooler than normal airmass already in place.
Westerly winds shift northwesterly today as a wave embedded within the trough swings through the region though little to no precip anticipated with this system outside a couple light rain-snow showers over far northern Lake Huron. Gradient weakens latter half of today allowing for a modest reduction in winds (falling below 20kts) going into the overnight period. Stronger west turning northwest flow redevelops daytime Sunday as low pressure tracks over eastern Ontario/Quebec re-tightening the local gradient. Strongest winds expected over the central and northern portions of Lake Huron where peak gusts reach 25-30kts. Small craft advisories likely will need to be reissued for the Saginaw Bay and potentially portions of the Thumb nearshore waters as a result. Gusts closer to 20kts favored over the southern portions of the region.

PREV DISCUSSION
Issued at 1211 AM EDT Sat Apr 20 2024

AVIATION...

VFR conditions will prevail through tonight with west winds to around 10 knots or less. Greater cold air will push into southeast Michigan throughout the morning steepening the low level lapse rates. This will support a healthy diurnal cumulus response by late this morning and early afternoon with a BKN to periodically OVC VFR deck at around 5-6kft. Winds will continue to be out of the west with daytime mixing yielding gusts to around 25 knots during this afternoon. Decreasing clouds and winds then expected during the evening.

DTW THRESHOLD PROBABILITIES...

* None



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

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

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