Sunrise 6:01 AM   Sunset 8:51 PM Moonrise 3:04 PM   Moonset 2:46 AM

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LHZ464 Expires:202405180945;;396640 Fzus63 Kdtx 180140 Glflh
open lake forecast for lake huron national weather service detroit/pontiac mi 940 pm edt Fri may 17 2024
for waters beyond five nautical miles off shore on lake huron
waves are the significant wave height - the average of the highest 1/3 of the wave spectrum. Occasional wave height is the average of the highest 1/10 of the wave spectrum.
Synopsis - Showers depart the area tonight giving way to a high pressure center, 29.90 inches. Light winds bring chances for fog overnight into tomorrow morning. The next low pressure system is expected to move in Monday night into Tuesday.
lhz363-462>464-180945- lake huron from sturgeon point to alabaster mi beyond 5nm off shore- lake huron from port austin to harbor beach beyond 5nm off shore- lake huron from harbor beach to port sanilac beyond 5nm off shore- lake huron from port sanilac to port huron beyond 5nm off shore- 940 pm edt Fri may 17 2024
Rest of tonight - East winds 5 to 10 knots. Patchy fog after midnight. Waves 2 feet or less. Saturday - Southeast winds 5 to 10 knots. Patchy dense fog. Waves 2 feet or less. Saturday night - Northeast winds 5 to 10 knots veering to the southeast in the late evening and overnight. Waves 2 feet or less. Sunday - South winds 5 to 10 knots backing to the east early in the afternoon. Waves 2 feet or less. Sunday night - Northeast winds 5 to 10 knots early in the evening becoming light and variable. Waves 2 feet or less. Monday - Southeast winds 5 to 10 knots increasing to 10 to 15 knots. A chance of showers late in the afternoon. Waves 1 to 3 feet. Tuesday - South winds 10 to 15 knots. A chance of showers. Rain showers likely in the late evening and early morning. Waves 2 to 4 feet. Wednesday - South winds 10 to 15 knots increasing to 15 to 20 knots in the late morning and early afternoon - .then becoming southwest 10 to 15 knots until early morning. Showers likely early in the morning - .then a chance of showers. Waves 3 to 5 feet.

LHZ400
No data

FXUS63 KDTX 180537 AFDDTX

Area Forecast Discussion National Weather Service Detroit/Pontiac MI 137 AM EDT Sat May 18 2024

KEY MESSAGES

- Areas of fog developing overnight.

- An Air Quality Alert is in effect for portions of Southeast Michigan Saturday, including Metro Detroit.

- Very warm and muggy conditions will be in-place this weekend with additional opportunities for thunderstorms Sunday and again early next week.

AVIATION

Low stratus and fog will fill in over the area overnight with IFR to occasional LIFR conditions. This will be especially true from KPTK south. Fog will dissipate between 12z-14z Saturday morning with VFR conditions thereafter. Winds will remain under 10 knots and more or less from the southeast.

For DTW/D21 Convection...Thunderstorms are not expected during this forecast period.

DTW THRESHOLD PROBABILITIES...

* High for ceilings aob 5kft overnight, low Saturday morning.

* Medium for ceilings and visibilities to drop below 200ft or 1/2SM overnight.

PREV DISCUSSION
Issued at 328 PM EDT Fri May 17 2024

DISCUSSION...

Partial clearing after morning showers has allowed for areas of sufficient insolation which converts building instability to surface- based CAPE. Diurnal convective development has initiated in isolated to widely-scattered fashion with surface dewpoints near 60F. Severe threat remains quite low given 0-6 km bulk shear values AOB 25 knots, therefore expect mostly short-lived pulse-like thunderstorms.
Latest CAMs suggest a slight increase in coverage with the arrival of a low-amplitude shortwave aloft. Varying storm motions possible as a weak low pressure system/triple-point stalls over Midland.
Multiple boundaries within the vicinity offer several additional point-sources for lift, augmented by MUCAPEs of 750-1250 J/kg.
Steepest lapse rates should be located within the 500-400 mb level, exceeding 8 C/km for part of the afternoon while the lower layer settles closer to moist adiabatic. Some pea-sized hail and few gusts to 40 mph are the main threats today. Storms wane after 9 PM as the mid-levels warm slightly and surface-based activity is cut-off by the development of a nocturnal inversion. A couple lingering showers are possible early tonight before the surface pattern gets washed out.

Weak ridging ensues Saturday with anticyclonic flow noted above 700 mb. Dewpoints remain elevated (near 60F), but forecast soundings reveal thermodynamic profiles that are a bit too warm to facilitate convective updrafts. High temperatures warm to near 80F for most areas while light southeast winds draw slightly cooler air to the coastal communities off the lakes. Clouds thin heading into the afternoon hours as a subsidence inversion develops between 800 and 700 mb.

Flow veers southwesterly Sunday as a deep closed low drifts into northwestern Ontario. An attendant cold front extending well south of the surface reflection washes out over Lake Michigan midday as the warm advection arm traces back to northern Texas. Locally, temperatures top out well above normal as highs peak in the low to mid 80s marked by 850 mb temps of 14-15C. Note that some model variance remains between the ensemble and deterministic solutions as it pertains to thermodynamics. Additional differences noted in QPF magnitude/extent, but most solutions do agree that some convective storms should arise during the PM hours. Dewpoints in the lower 60s and steep low-level lapse-rates should activate surface parcels as shortwave perturbations embedded within the periphery of the leading height fall gradient arrive. Agreed with NBM PoP increase to Slight Chance across most of the forecast area. Low-end potential exists for additional storms Sunday night as a more robust CVA response streams through the drying mid-levels.

An unsettled pattern continues early next week as the synoptic ridge becomes stationary over The Appalachians and the northern stream jet remains active just off to the west. Several shortwaves will eject eastward out of stalled longwave trough Monday and Tuesday with additional ThetaE intrusions. Strong to severe storms would be most probable Tuesday as dewpoints peak in the mid 60s and 0-6 km bulk shear approaches 30 knots. The upper level configuration unlocks Wednesday as an energetic low drops into the Pacific Northwest from the Gulf of Alaska triggering ridge amplification over the Intermountain West. This kicks the jet eastward Wednesday along with a cold front which could initiate some preceding convection locally, depending on timing and southern stream wave interactions. Post- frontal conditions should be noticeably cooler for the back half of next week with a return to near-normal readings.

MARINE...

Scattered showers potentially producing thunderstorms will move over Lake Huron and Lake Erie this afternoon as a weak low pressure center and frontal boundary move across the region. Gentle southerly winds over Lake Huron will back to become more easterly this evening, decreasing down to about 5 knots. These calm winds and moist conditions will lead to some patchy fog overnight. Fog over the lake will hang around for a bit longer than over land, lasting into the early afternoon. Benign and predominantly southerly winds persist through the weekend with a weak cold front moving through on Sunday. Potential for more unsettled conditions Monday night into Tuesday as a stronger system moves into the area. This system will bring moderate southerly winds as well as showers and thunderstorms.

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

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