Sunrise 6:18 AM   Sunset 9:04 PM Moonrise 12:14 PM   Moonset 2:09 AM

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LMZ848 Whitehall To Pentwater Mi- 1005 Pm Edt Wed May 15 2024
Rest of tonight - Northeast winds 5 to 10 knots veering southeast 10 to 15 knots after midnight. Mostly clear. Waves 1 to 3 feet. Thursday - South winds 10 to 15 knots. Partly Sunny with a slight chance of showers and Thunderstorms. Waves 1 foot or less. Thursday night - South winds 5 to 10 knots. Partly cloudy with a chance of showers and Thunderstorms. Waves 1 foot or less. Friday - South winds 5 to 10 knots veering northwest late in the day. Partly Sunny. Waves 1 foot or less. Friday night - Northeast winds 5 to 10 knots veering east toward daybreak. Partly cloudy. Waves less than 1 foot. Saturday - East winds 5 to 10 knots veering west 10 to 15 knots, then veering north late in the day. Mostly Sunny. Waves around 1 foot. Sunday - Northwest winds 10 to 15 knots. Sunny. Waves 1 to 2 feet. Monday - South winds 10 to 15 knots veering southwest late in the day. Mostly Sunny. Waves around 1 foot.

LMZ800
No data

FXUS63 KGRR 152341 AFDGRR

Area Forecast Discussion National Weather Service Grand Rapids MI 741 PM EDT Wed May 15 2024

KEY MESSAGES

- Chilly night; showers and storms return late Thursday

- Above normal temps with a low risk of showers into the weekend

- Potentially stormy early next week

DISCUSSION
Issued at 340 PM EDT Wed May 15 2024

- Chilly night; showers and storms return late Thursday

Dry air mass with sfc dew pts in the 30s/40s continues to infiltrate the state from the north/northeast. As winds slacken off tonight under mostly clear skies, expect chilly overnight low temps in the lower to mid 40s. Some thin cirrus is expected to arrive from the west late.

After a fairly sunny start to the day, the approach of a shortwave from the west Thursday brings increasing clouds in the afternoon along with a chance of a shower or storm by late in the day. Developing southerly flow draws up sfc dew pts in the lower 50s which could set off a few diurnal showers and storms after 21Z or so. CAMs look to favor the area from GRR to the south especially AZO.

Limiting factor for any stronger/svr storms looks to instability with only about 500 J/KG SBCape or so vs 1500 J/KG to our west over WI where SPC Day2 MRGL risk exists. Deep layer shear does increase however to near 40 kts by the end of the day.

Shower/tstm coverage becoming more numerous for Thursday night as the shortwave and associated sfc front draws closer and the remnant WI convection heads our way. Again instability looks too meager to support any stronger storms despite existence of decent shear.

- Above normal temps with a low risk of showers into the weekend

The risk for spotty showers and storms will linger into Friday and Saturday, though overall synoptic forcing will be weak. For Friday, expect weakening low pressure north of Lake Superior, with an ill- defined front/boundary trailing south across the Great Lakes. This feature, albeit weak, will still support a low chance (20-30%) for convection, particularly during the afternoon with the addition of daytime heating. Low chance (20%) for showers continues Saturday with daytime heating and weak upper low pushing into Ohio Valley likely to throw moisture north in the region. At this time, rain chances appear very low for Sunday.

Overall, the Friday/Saturday/Sunday period will likely be more indicative of an early summer pattern; though small chances for convection will exist, sky conditions during the day should average partly to perhaps mostly sunny, and highs will reach the 70s to near 80 /some 4-8F above normal/.

- Potentially stormy early next week

Deterministic and ensemble model output has been relatively consistent the last few runs showing a strong mid level impulse (at least for the month of May) progressing steadily ENEwd from the California coast late Sunday to the Upper MS Valley and Great Lakes region by Tuesday/Wednesday. Strong dynamics, low level moisture advection in advance of surface feature, and May sun angle point to the potential for storminess in West Michigan about Tuesday (give or take) before cooler air arrives Wednesday-ish.

Not surprising at this forecast projection, much uncertainty exists regarding timing/strength, though it will be worth monitoring as we head toward early next week. High temperatures nearing 80 Monday and Tuesday will cool by Wednesday.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
Issued at 722 PM EDT Wed May 15 2024

VFR conditions expected though the TAF period. A few lower clouds and showers work across Lake Michigan late in the TAF period but not confident enough to put it in the TAFS at this time.

MARINE
Issued at 340 PM EDT Wed May 15 2024

Typical diurnal enhancement to the wind field in the marine environment has occurred this afternoon as earlier northeast breezes have turned to the north-northwest with some gusts now up to 20 kts. Wave heights have responded and now seeing 2-3 footers along much of the coast. These enhanced winds/waves will continue through sunset before relaxing and turning offshore again. Other than that, not really seeing any periods of hazardous winds and waves for the remainder of the week and actually through the bulk for the upcoming weekend.

GRR WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...None.

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