Sunrise 6:18 AM   Sunset 9:04 PM Moonrise 12:13 PM   Moonset 2:09 AM

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LMZ849 Pentwater To Manistee Mi- 405 Am Edt Wed May 15 2024
Early this morning - Northeast winds 10 to 15 knots. Clear. Waves 1 to 2 feet. Today - North winds 10 to 20 knots. Sunny. Waves 2 to 3 feet. Tonight - Northeast winds 10 to 20 knots veering southeast 5 to 15 knots after midnight. Mostly clear. Waves 2 to 3 feet. Thursday - Southeast winds 5 to 10 knots veering southwest. Partly Sunny with a slight chance of rain showers. Waves 1 foot or less. Thursday night - South winds 5 to 10 knots. Mostly cloudy with a chance of rain showers and a slight chance of Thunderstorms. Waves 1 foot or less. Friday - South winds 10 to 15 knots veering west, then veering north late in the day. Partly Sunny. Waves around 1 foot. Saturday - Northeast winds around 10 knots backing north. Mostly Sunny. Waves around 1 foot. Sunday - West winds 10 to 15 knots. Mostly Sunny. Waves around 1 foot.

LMZ800
No data

FXUS63 KGRR 151057 AFDGRR

Area Forecast Discussion National Weather Service Grand Rapids MI 657 AM EDT Wed May 15 2024

KEY MESSAGES

- Drying Out Today, But Showers/Storms Return Late Thursday

- Showers/Storms Thursday night and Friday

- Chance of Stronger Storms Monday/Tuesday

DISCUSSION
Issued at 319 AM EDT Wed May 15 2024

- Drying Out Today, But Showers/Storms Return Late Thursday

The latest GOES low and mid level WV imagery shows a slow erosion in moisture across central Lower Michigan this morning. RAP13 and GFS relative humidity layer (850mb-250mb) trends indicate only a gradual decrease in moisture from N to S today. As such, the expectation is for areas near and north of I-96 to see sun break through by mid to late morning, but areas south of I-96 (and especially toward I-94) may take until early to mid afternoon for clouds to erode. Any leftover light showers and sprinkles are expected to end by mid morning across our far southern forecast area near I-94.

For Thursday, a weakening upper trough will push into the Great Lakes region. Synoptic forcing for ascent will somewhat be there with the upper trough and a decent ULJ, though GFS/HRRR model soundings show equilibrium levels not getting much above 500mb-400mb during the daytime, indicative of modest convective potential. Low level moisture advection may take some time to materialize across the region, impacting areas near and south of I-96 first. 00z HRRR guidance does show some marginal SB CAPE possible in this area, perhaps a few hundred J/kg by late afternoon. There could be a scattering of showers and a few thunderstorms possible Thursday afternoon especially near and west of U.S. 131, but it appears most precipitation will hold off until after dark.

- Showers/storms Thursday night and Friday

We'll have several chances for showers and thunderstorms during the period. However, much of the weekend looks dry.

Thursday night and Friday will see the highest chances for rain as a cold front moves across the cwa. Low to moderate instability is progd with this system with MUCAPE values in the 500-1k j/kg range.
Isolated to scattered storms are likely during this time frame.
Shear values in the 35-40 kt range suggest that a few storms may skew toward being strong late Thursday night and Friday morning, however early morning timing usually doesn't bode well for stronger storms and the short wave accompanying the front isn't all that impressive either.

- Chance of stronger storms Monday/Tuesday

The weather early next week bears watching. West southwest flow aloft will bring several short waves from the Plains into the Great Lakes and each will have an impressive surface low. The first low will develop Sunday night over KS/IA and then track toward Lower MI Monday. The GFS isn't as aggressive as the Euro is but develops showers/storms near a wave on a frontal boundary that moves across the cwa Monday. Most of the instability and dynamics remain south of the cwa with the GFS, but nonetheless produces some rain.

The bigger deal may be Tuesday as both models produce an impressive surface low over the MO Valley and push a warm front toward the cwa.
Additionally, 40-50kts shear develop in response to a strong LLJ to the south and higher mid level winds poking in from the southwest.
This scenario has the potential for stronger storms.

Highs will be in the 70s through the period.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
Issued at 653 AM EDT Wed May 15 2024

No changes to the going forecast. Showers have ended at the terminals. However, there remains some MVFR stratocu at JXN. That should lift within the next few hours. Otherwise, clouds will thin today and VFR conditions are expected through the rest of the period.

MARINE
Issued at 319 AM EDT Wed May 15 2024

Broad NE flow over Lake Michigan will likely turn N/NW after 18z, leading to an uptick in wave action across all zones, especially south of Pentwater. Waves may increase to 2-3 ft by this afternoon. Conditions do not look to warrant a SCA at this time.
From Thursday into the first part of the weekend, wave action will likely hold in the 1-2 ft range.

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

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