Sunrise 6:35 AM   Sunset 8:48 PM Moonrise 2:34 AM   Moonset 11:54 AM

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LMZ848 Whitehall To Pentwater Mi- 1005 Pm Edt Tue Apr 30 2024
.small craft advisory in effect from 5 am edt Wednesday through Wednesday afternoon - .
Rest of tonight - Southeast winds 15 to 25 knots. Partly cloudy through about 2 am, then mostly cloudy with a chance of rain showers overnight. Waves around 1 foot building to 2 to 4 feet toward daybreak. Wednesday - Southwest winds 15 to 25 knots. Mostly Sunny. Waves 3 to 5 feet. Wednesday night - Southwest winds 10 to 15 knots veering northwest late at night, then veering northeast toward daybreak. Partly cloudy with a slight chance of rain showers. Waves 2 to 3 feet subsiding to 1 to 2 feet after midnight. Thursday - East winds 10 to 15 knots increasing to 15 to 20 knots late in the day. Mostly cloudy with a chance of rain showers. Waves around 1 foot. Thursday night - Southeast winds 15 to 20 knots. Rain showers likely and a chance of Thunderstorms. Waves 2 to 3 feet. Friday - South winds 15 to 20 knots veering southwest. Rain showers likely. Waves 2 to 3 feet. Saturday - Northeast winds around 10 knots backing northwest. Partly Sunny. Waves around 1 foot. Sunday - Northwest winds around 15 knots. Mostly Sunny. Waves 1 to 2 feet.

LMZ800
No data

FXUS63 KGRR 302350 AFDGRR

Area Forecast Discussion National Weather Service Grand Rapids MI 750 PM EDT Tue Apr 30 2024

KEY MESSAGES

- Gusty winds and a shower risk later tonight into Wednesday morning

- Warmer than normal temperatures ahead

- Several Chances for showers and storms ahead

DISCUSSION
Issued at 255 PM EDT Tue Apr 30 2024

- Gusty winds and a shower risk later tonight into Wednesday morning

A 40 knot low level jet moves into the region late tonight into Wednesday morning. This feature advects in a moist air mass with PWAT values progged to reach around an inch based off of the ensemble guidance. Given the moisture and lift, some shower activity is expected to track in from the west as this the low level jet arrives. If the upstream convection that develops this evening diminishes slower than expected, a few thunderstorms could make it across the lake, mainly around daybreak. SPC HRRR MU CAPE values is still struggling to show much if any instability so we will keep the precipitation as showers for now. Any heavier downpour could lead to gusty winds. A better shot for gusty winds will be as mixing develops Wednesday morning. Base on projected heights and the winds at those levels, we should see gusts topping 30 mph at times.

- Warmer than normal temperatures ahead

Overall zonal flow will continue through the rest of the week and into next week. The positive height anomalies favor continued warm air advection through this period. Latest Ensembles and anomalies continue to show a prolonged period of +1 or greater anomalous warmth into next week. That should keep daytime highs 5 to 10 degrees above normal. This correlates to Highs in the 70s through the weekend.

- Several Chances for showers and storms ahead

A strong frontal boundary in between a retreating high and a large upper level low moving along the Canada border should provide enough moisture and instability for showers and storms late Thursday night into Friday morning. The bulk of the cold air associated with that system should remain north. There is a strong short wave associated with that system and given the current gradient there should be some mid to low level winds should provide enough shear for convection.
Latest mid range models continues to downplay the moisture associated with it through there remains PWATS of an inch to 1.25 inches.

Another opportunity for precipitation will come in the form of a tertiary trough on the back side of the above mentioned upper level low. As that low exits to the northeast it will swing an elongating trough through the Great Lakes. Behind that trough is some cold air that though above freezing, current 850 mb temps have it +2 to +3C which is should allow for a decent cold frontal boundary that could aid convection. So isolated storms are possible at this point, however it is a ways ahead so confidence is low.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
Issued at 750 PM EDT Tue Apr 30 2024

VFR is likely for much of the next 24 hours, except for between 09 and 15 Z when portions of the area could have MVFR ceilings moving through. Thunderstorms currently in Iowa are likely to fall apart before they arrive in West Michigan late tonight, but scattered light rain showers could survive. There may be a few-hour period of 30 knot Low-Level Wind Shear shortly before to just after sunrise (about 1030Z). Later in the morning through the afternoon, these winds above the ground will mix down as 25-30 knot gusts from the southwest becoming west.

MARINE
Issued at 255 PM EDT Tue Apr 30 2024

A low level jet will be moving into the nearshore zones overnight and Wednesday morning. This feature will support increasing winds and building waves. The flow will initially be south southeast later tonight but it will veer to the southwest during the morning. We will issue a small craft advisory for most marine zones as a result.

GRR WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...Small Craft Advisory from 5 AM to 4 PM EDT Wednesday for LMZ845>849.

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