Sunrise 6:25 AM   Sunset 8:43 PM Moonrise 3:42 AM   Moonset 3:42 PM

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LCZ423 320 Am Edt Fri Apr 19 2024
.strong Thunderstorms approaching the waters - .
the areas affected include - . Detroit river - . Michigan waters of lake erie from detroit river to north cape mi - .
at 320 am edt, doppler radar indicated strong Thunderstorms, capable of producing winds up to 30 knots. These Thunderstorms were located along a line extending from 6 nm northwest of bolles harbor of refuge to 9 nm south of north cape, moving northeast at 40 knots.
strong Thunderstorms will be near - . Monroe harbor, bolles harbor of refuge, north cape, luna pier, and detroit beach around 325 am edt. Stony point and woodland beach around 330 am edt. Estral beach and gibraltar around 340 am edt. Lake erie metropark harbor and detroit river light around 345 am edt. Elizabeth park marina around 350 am edt.
other locations impacted by strong Thunderstorms include woodland beach, stony point, gibraltar, estral beach, and detroit beach.
precautionary/preparedness actions - .
mariners can expect gusty winds up to 30 knots, locally higher waves, and lightning strikes. Boaters should seek safe harbor immediately until these storms pass.
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lat - .lon 4173 8345 4173 8350 4180 8350 4195 8337 4197 8328 4217 8321 4219 8319 4218 8313 4212 8312 4203 8315 4196 8311 4180 8333 4172 8341 4172 8347

LCZ400
No data

FXUS63 KGRR 040749 AFDGRR

Area Forecast Discussion National Weather Service Grand Rapids MI 349 AM EDT Sat May 4 2024

KEY MESSAGES

- Fog and stratus through this morning

- Showers and storms expected tonight

- Dry Monday, Otherwise Unsettled Most of Next Week

- Cooling Off Toward the End of Next Week

DISCUSSION
Issued at 349 AM EDT Sat May 4 2024

- Fog and stratus through this morning

Our first focus out of the gate this morning is the fog/stratus that is steadily spreading westward from SE Lower. This can be seen well over the past couple of hours on the nighttime microphysics channel as the thicker cirrus has thinned out a bit, and as the low clouds/fog are moving west of the cirrus shield.

Our initial thought this morning is that stratus will be more favored vs. fog. This moisture is advecting/expanding to the west as low level moisture with the system yesterday did not make it far east of the area. Then, as the flow has become more ENE, it is taking that moisture and bringing it back over the area, or expanding it to the area as the cooling atmosphere condenses.

There is a bit of wind aloft this morning, which is why we favor stratus vs. dense fog. That said, winds have decoupled well, and a couple of sites to our N and E have dropped down to less than a mile in fog. We will continue to monitor the trends this morning. Once the sunrises, the low level moisture will lift and mix out, probably toward noon/early afternoon. Then there should be a fair amount of sunshine and warmer air once again.

- Showers and storms expected tonight

The break in the weather we see today will be brief, with showers and storms to become likely toward and after midnight tonight. We will see a short wave try to approach the area tonight from the WSW.
This short wave will be weakening as it approaches the area, but will hold on to enough of its strength the drive a cold front into the area.

The cold front will be able to work with some instability ahead of it, on the order of a few hundred J/kg of MU CAPE into the night.
Elevated LI's are forecast to be around -1 to -3C ahead of the front. Models are in fairly good agreement bring a broken line of showers and storms through. With the instability being elevated, and it being night time, severe weather threat is fairly low. Most of, or all of this shower and storm activity should be east of the area toward daybreak on Sunday. Clouds should clear out through the day, and temperatures will climb up to around 70 with just a tad cooler air coming in.

- Dry Monday, Otherwise Unsettled Most of Next Week

Guidance is in good agreement showing high pressure both aloft and at the sfc in place on Monday, providing mostly sunny and pleasant conditions with highs 70-75. There is also still good agreement that a shortwave and sfc cyclone will impact the area Tuesday afternoon and night, with pops of 60-90 percent during this time.

Initially we see a warm front lifting north Tuesday afternoon but then the cold front sweeps in quickly from the west Tuesday night as a deepening sfc low tracks through WI. Can't rule out some strong to severe storms, but the main risk could end up being south of MI since the warm sector may not make it this far north or stick around long enough due to occlusion of the sfc system.

A period of dry weather is probable behind the Tuesday night system for at least the first half of Wednesday, but another shortwave and sfc trough associated with approaching longwave trough brings a renewed threat of showers and storms by Wednesday evening. A repeat of that is possible Thursday too as additional waves rotate through the base of the nearing upper trough.

- Cooling Off Toward the End of Next Week

Unsettled/showery pattern persists through the end of next week as the old nrn Plains upper low continues slowly eastward and eventually sets up shop near Lake Superior. Our warm stretch finally comes to an end by Thursday or Friday as progressively colder air filters south around the upper low. Below normal temps appear likely as we head into next weekend.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
Issued at 156 AM EDT Sat May 4 2024

Areas of IFR/LIFR cigs and vsbys expected through mid morning Saturday due to fog and low stratus patches drifting westward from the east side of the state. Conditions turning VFR again by Saturday afternoon with a scattered to broken cumulus deck lifting to around 4500 ft. An isolated shower or tstm cannot be ruled out inland from Lk MI in the late afternoon but the potential (and the coverage) looks too low to include in the TAFs. The primary risk of showers and storms holds off until after 06Z Sunday with perhaps the exception of MKG which may see that threat materialize by 04Z.

MARINE
Issued at 349 AM EDT Sat May 4 2024

There is a potential that we may need a Small Craft Advisory for later tonight into Sunday. It is then that the front will be moving through, and a decent gradient sets up behind it from the NNW as the high builds in from the west. Not confident enough yet at this point to hoist an advisory.

Other than tonight, it looks like winds will generally stay under thresholds with a lighter gradient in place.

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

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