Sunrise 6:47 AM   Sunset 8:39 PM Moonrise 7:40 PM   Moonset 5:32 AM

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LMZ847 Grand Haven To Whitehall Mi- 1005 Pm Edt Tue Apr 23 2024
.small craft advisory in effect through Wednesday evening - .
Rest of tonight - North winds to 30 knots. Partly cloudy. Waves 6 to 8 feet. Wednesday - North winds 15 to 25 knots. Sunny. Waves 4 to 6 feet. Wednesday night - North winds 10 to 20 knots veering east after midnight. Mostly clear. Waves 2 to 4 feet subsiding to 1 to 2 feet after midnight. Thursday - Southeast winds 10 to 15 knots veering west late in the day. Sunny. Waves around 1 foot. Thursday night - Northeast winds 5 to 15 knots becoming southeast 15 to 25 knots after midnight. Mostly clear. Waves 2 to 3 feet. Friday - Southeast winds to 30 knots. Mostly cloudy with a chance of rain showers. Waves 3 to 5 feet. Saturday - South winds to 30 knots. Rain showers likely. Waves 6 to 8 feet. Sunday - South winds 20 to 25 knots. Rain showers likely. Waves 3 to 5 feet.

LMZ800
No data

FXUS63 KGRR 232331 AFDGRR

Area Forecast Discussion National Weather Service Grand Rapids MI 731 PM EDT Tue Apr 23 2024

KEY MESSAGES

- Scattered Showers and Storms This Evening

- Widespread Freezing Temperatures Wednesday Night

- Showers and Thunderstorms Over the Weekend, Warmer

DISCUSSION
Issued at 335 PM EDT Tue Apr 23 2024

- Scattered Showers and Storms This Evening

Scattered diurnal showers and storms expected this evening underneath the cold pool and trough aloft should quickly fade toward midnight. However a few showers could linger past midnight in far eastern sections (Hwy 127) related to a secondary sfc trough rotating south through ern Lwr MI.

Clearing skies follow from north to south on Wednesday as cold dry air mass pours in, with sunny skies emerging by early afternoon as sfc dew pts drop into the teens north and 20s south.

- Widespread Freezing Temperatures Wednesday Night

Guidance has been consistently showing high probabilities for sub freezing temperatures early Thursday morning as sfc high settles overhead with sfc dew pts of 15 to 20 in place. There are some questions regarding cloud cover with the potential for patches of mid and high level clouds floating through the northwest flow aloft. At this time those clouds do not look too extensive or thick and the timing is very late at night.

Coldest temps in the mid 20s per NBM are expected to be over the nrn and ern portions of GRR CWFA with temps 29-32 anticipated near and south/west of GRR. Will post an areawide Freeze Watch now given the already high potential.

- Showers and Thunderstorms Over the Weekend, Warmer

Cold high pressure will bring more freezing temperatures on Friday morning, before moving east with return flow of warmer and moister air beginning Friday afternoon and continuing through the weekend.

THe large scale pattern features persistent western CONUS troughing with rising heights to the east. Gulf inflow in the deep southwest flow across the east-central U.S. should help fuel an axis of potentially heavy rains across the greater Mississippi Valley and occasionally into Lower Michigan as surface lows track through the western Great Lakes.

ALthough there are the usual timing issues with individual shortwave troughs, ensemble data indicates that the highest chances for rain/thunder appears to be Friday night and again during Sunday with a potential break in the rain coming early next week under shortwave ridging.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
Issued at 726 PM EDT Tue Apr 23 2024

An approaching wave of low pressure will encounter an unstable airmass over Southwest Lower MI leading to several hours of thunderstorm potential this evening. Around 04z the storms should be pushing southeast of KJXN. There will be a sharp wind shift dropping down from the north on the backside of these storms which will impact the TAF sites. Local gusty winds and some hail will be possible with any stronger storms. MVFR clouds will flow in behind the system but they are predicted to break up and become scattered closer to daybreak.

MARINE
Issued at 335 PM EDT Tue Apr 23 2024

South-southwest winds to 30 kts will shift northerly tonight behind a passing cold front and could even briefly flirt with gales. Small Craft Advisory remains in effect through 8 PM Wednesday.

Winds and waves subside quickly Wednesday night into Thursday as surface high pressure settles in, then winds increasing out of the southeast late Thursday night into Friday.

Southerly flow should prevail over Lk MI through most of the upcoming weekend as a warmer/more humid air mass arrives. It's quite possible the southerly winds will be strong enough to require small craft advisories, at least at times. Other marine threats over the weekend could include occasional thunderstorms and areas of fog as dew points above 50 arrive atop chilly water temps in the mid 40s.

GRR WATCHES/WARNINGS/ADVISORIES
MI...Freeze Watch from late Wednesday night through Thursday morning for MIZ043>046-050>052-056>059-064>067-071>074.
MARINE...Small Craft Advisory until 8 PM EDT Wednesday for LMZ844>849.

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