Sunrise 6:16 AM   Sunset 9:01 PM Moonrise 3:18 PM   Moonset 2:59 AM

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LMZ844 St Joseph To South Haven 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. Mostly clear. Areas of dense fog. Waves less than 1 foot. Today - South winds 5 to 10 knots veering southwest. Sunny. Areas of dense fog until midday. Waves less than 1 foot. Tonight - South winds 5 to 10 knots veering southwest toward daybreak. Partly cloudy. Waves 1 foot or less. Sunday - Northwest winds 5 to 10 knots becoming around 10 knots late in the day. Mostly Sunny. Waves around 1 foot. Sunday night - Northeast winds 5 to 10 knots veering southeast toward daybreak. Partly cloudy. Waves around 1 foot. Monday - South winds 10 to 15 knots. Mostly Sunny with a chance of rain showers. Waves around 1 foot. Tuesday - South winds 10 to 15 knots. Partly Sunny with a chance of showers and Thunderstorms. Waves 1 to 2 feet. Wednesday - Southwest winds 20 to 25 knots veering west 15 to 20 knots late in the day. Mostly Sunny with a chance of rain showers. Waves 2 to 4 feet.

LMZ800
No data

FXUS63 KGRR 181052 AFDGRR

Area Forecast Discussion National Weather Service Grand Rapids MI 652 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 648 AM EDT Sat May 18 2024

Nighttime fog satellite imagery shows some stratus/fog trying to creep into Jackson and Calhoun counties. It's possible JXN gets clipped with some stratus for an hour or so, but more likely that patchy dense fog develops there through 13z. Otherwise, patchy dense fog will burn off by 13z leading to clear skies through the rest of the period. Patchy fog is once again possible after 06z Sunday.

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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