Sunrise 6:15 AM   Sunset 9:07 PM Moonrise 3:21 PM   Moonset 3:03 AM

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LMZ847 Grand Haven To Whitehall Mi- 405 Am Edt Sat May 18 2024
.dense fog advisory in effect until noon edt today - .
Early this morning - Southeast winds around 5 knots. Partly cloudy. Areas of dense fog. Waves less than 1 foot. Today - Southeast winds 5 to 10 knots veering south. Sunny. Areas of dense fog until midday. Waves 1 foot or less. Tonight - South winds 10 to 15 knots veering southwest toward daybreak. Partly cloudy with a slight chance of rain showers and isolated Thunderstorms. Waves around 1 foot. Sunday - Northwest winds 10 to 15 knots. Mostly Sunny. Waves around 1 foot. Sunday night - North winds 5 to 10 knots veering southeast 10 to 15 knots toward daybreak. Partly cloudy with a slight chance of showers and Thunderstorms. Waves around 1 foot. Monday - South winds 10 to 20 knots. Partly Sunny with a chance of rain showers. Waves 2 to 3 feet. Tuesday - South winds 10 to 20 knots. Mostly cloudy with a chance of showers and Thunderstorms. Waves 1 to 3 feet. Wednesday - Southwest winds 20 to 25 knots. Partly Sunny with a chance of rain showers. Waves 4 to 6 feet.

LMZ800
No data

FXUS63 KGRR 180733 AFDGRR

Area Forecast Discussion National Weather Service Grand Rapids MI 333 AM EDT Sat May 18 2024

KEY MESSAGES

- Very mild weekend

- Low chance of showers late tonight and Sunday afternoon

- Wet Monday through Wednesday, Strong storms possible Tuesday

DISCUSSION
Issued at 333 AM EDT Sat May 18 2024

- Very mild weekend

Summerlike conditions are forecast this weekend with high temps reaching the low to mid 80s today and Sunday (except cooler near Lake MI as a weak gradient is conducive for lake breeze formation today and tomorrow). Ample sun is expected today after patchy early morning fog with nothing more than some sct-bkn fair wx cu late this morning and aftn mainly near to east of US-131.

- Low chance of showers late tonight and Sunday afternoon

A weakening line of showers and perhaps an isolated storm will move in from the wnw into our nw fcst area very late tonight. The vast majority of our area will not receive measurable rainfall overnight.

Then for Sunday a weak frontal boundary will focus development of a few showers and isolated storms mainly east to se of KGRR in the aftn. Moderate instability will develop SE of KGRR with sb capes reaching 1k-2k j/kg. However no svr wx is expected given weak shear and weak forcing and limited moisture.

- Wet Monday through Wednesday, Strong storms possible Tuesday

Southwest flow aloft is usually a setup that can be stormy across the Great Lakes during the spring and that will be the case here Monday through Wednesday. Of the three days, Tuesday will garner the most concern.

A short wave will track from the central Plains toward Wisconsin by Monday morning along with a weak surface reflection. We'll probably see some showers and a few storms move over the lake and affect the northwest cwa by Monday and afternoon with some of the convection eventually drifting east Monday night. There's decent instability...MUCAPE around 1500 j/kg Monday afternoon and shear values climb to around 35kts over the northwest cwa. So this area may be favored late Monday for a few stronger storms.

A stronger short wave and surface low will emerge from the Plains Tuesday and push a warm front through mid day Tuesday followed by a cold front Tuesday evening. Bulk shear increases during the day Tuesday and given the warm front moving through, spinups are a concern. Dynamics are a bit stronger Tuesday night. However, instability may be a bit weaker given the lack of heating. That said, the models do show a mid level speed max around 65kts moving across the cwa 06z Wednesday in conjunction with a 60 kt LLJ. The evolution of this system bears watching.

Precipitation may linger through Wednesday as the upper low slowly moves east. Overall, the Monday-Wednesday timeframe may be rather wet with QPF in the 1-2 inch range.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
Issued at 134 AM EDT Sat May 18 2024

Skies are clear across the region, but some fog is beginning to develop along the lake shore. Short range models are not as bullish on IFR vsbys as they were yesterday morning. We included a tempo group for MVFR vsbys and we can adjust as conditions warrant. Current dewpoint depressions are a couple of degrees higher than last night at this time.

Any fog should burn off by 14z leading to VFR conditions the rest of the period.

MARINE
Issued at 333 AM EDT Sat May 18 2024

Patchy sporadic marine fog has been noted overnight and conditions are conducive for more of it to develop this morning. Therefore the marine dense fog advisory remains in effect through midday.
Otherwise winds and waves will stay well below Small Craft Advisory levels this weekend.

GRR WATCHES/WARNINGS/ADVISORIES
MI...Air Quality Alert until midnight EDT tonight for MIZ050-056-057- 064-071.
MARINE...Dense Fog Advisory until noon EDT today for LMZ844>849.

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