Sunrise 5:26 AM   Sunset 8:43 PM Moonrise 3:46 PM   Moonset 2:35 AM

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LSZ148 Expires:202405182100;;442697 Fzus73 Kdlh 182032 Mwsdlh
marine weather statement national weather service duluth mn 332 pm cdt Sat may 18 2024
lsz121-148-150-162-182100- 332 pm cdt Sat may 18 2024
.a strong Thunderstorm over western lake superior - .
the areas affected include - . Chequamegon bay-bayfield to oak point wi - . Lake superior west of a line from saxon harbor wi to grand portage mn beyond 5nm - . Oak point to saxon harbor wi - . Outer apostle islands beyond 5 nm from mainland - .
at 331 pm cdt, surface weather observations indicated a strong Thunderstorm, capable of producing winds to around 30 knots. This strong Thunderstorm was located near oak point, moving northeast at 45 knots.
locations impacted include - . Michigan island, madeline island, chequamegon bay, and apostle islands national lake shore.
precautionary/preparedness actions - .
mariners can expect wind gusts up to 33 knots, locally higher waves, cloud to water lightning strikes, small hail, and heavy downpours. Boaters should seek safe harbor until these storms pass.
&&
a severe Thunderstorm watch remains in effect until 1000 pm cdt for northwestern wisconsin - .and the adjacent waters of lake superior.
lat - .lon 4664 9070 4663 9073 4671 9080 4707 9021 4705 9018 4672 9040 4663 9069

LSZ100
No data

FXUS63 KDLH 192320 AFDDLH

Area Forecast Discussion National Weather Service Duluth MN 620 PM CDT Sun May 19 2024

KEY MESSAGES

- Rain arrives tonight and lingers through Monday. Total accumulations around 0.25" to 0.50"; locally higher and lower amounts possible.

- A larger system brings even more rain Tuesday through Wednesday with totals >1" possible for many areas. There could be some strong to severe storms on Tuesday as well.

- A little drier to end the week, but rain chances will persist into the weekend.

DISCUSSION
Issued at 407 PM CDT Sun May 19 2024

Today, we're under the influence of southerly warm air advection out ahead of an approaching low pressure system from the southwest. A weak wave aloft has been kicking off some showers, but the air has been so dry at the surface that most of it, except the heaviest showers, has been virga. We can expect this general cloudy and occasionally sprinkly weather to continue through the evening.

Tonight, the upper level trough and low pressure passing by will bring an area of rain to the region. The main swath of rain is expected to be somewhat quick-hitting, lasting about 6-9 hours through Monday late afternoon to early evening. PWATs will be around 90th percentile of climatology, but without excessive synoptic forcing and the aforementioned relatively quick duration. So, totals around 0.25"-0.50" are likely to be common, and there's pretty reasonable ensemble consensus around that.
We'll probably see some locally higher and lower amounts. Higher amounts will be more likely in east-central Minnesota into northwest Wisconsin where a bit of instability (<500 J/kg) may promote a few embedded thunderstorms. Strong to severe storms are not expected. We'll probably also see some areas of fog with this, though there isn't a strong signal for dense fog anywhere at this point.

There's likely to be a brief break in the rainfall Monday night such that it tapers off to scattered showers for most places. A few models are hinting that we could retain some elevated instability overnight though, so we'll have to keep an eye on that for the potential for some isolated non-severe storms, which would be most likely in the east-central Minnesota to northwest Wisconsin areas.

A much more potent low pressure system is still shaping up to impact the region Tuesday through Wednesday with a broad warm nose of moist Gulf of Mexico air headed towards the Northland.
PWATs will again be around that 90-95th percentile of climatology, so plenty of moisture out there. This time, we'll see a longer duration of rainfall (up to 15-20 hours or so), so it'll add up more. A broad synoptic rainfall with some embedded thunder will likely yield totals >1" for most areas (50-90% per NBM). Several ensemble members paint the possibility for higher totals approaching 3-4" as well locally. At this point, flash flooding doesn't seem like a big concern as the rainfall intensity, in general, probably won't be high enough to support that. However, the long duration of it could lead to some localized minor flooding. At the very least, areas that usually get filled with water when it rains, such as ditches and other low spots, will probably see some high water. The WPC has drawn a marginal risk (at least 5%)for excessive rainfall across the region, with a slight risk (at least 15%) for approximately the Twin Ports and points south.

In addition to the rain, we'll have higher potential for some thunderstorms with higher instability. The caveat with this system remains the storm track. Ensembles still have a fairly large range of possibilities as far as the low track goes, though funny enough, the inconsistency in low track has been pretty consistent in the past several runs (namely the ECMWF).
This is important because the northern extent of convection potential will depend on the track. If the track is further north, a wedge of potential instability around 1000 to 1500 J/kg or so could swing into our area Tuesday afternoon. There will be plenty of 0-6 km shear to promote some strong to severe thunderstorms, particularly in parts of northwest Wisconsin, if this pans out. Right now, the probably for severe storms sits at around 15% on Tuesday, with a slight risk for severe storms for parts of northwest Wisconsin per the SPC.

The rain is expected to taper to scattered wraparound showers Wednesday afternoon as low pressure moves into Ontario. Thursday will likely be a drier day, but there's still at least a 10-20% chance for some sort of rain as an amplified upper-level pattern remains. Another trough may swing through Friday, potentially bringing a cold front and shower/storm chances. The weekend may have some periodic rain as well.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
Issued at 620 PM CDT Sun May 19 2024

VFR conditions currently across the Northland. Radar is picking up on a few returns this evening but with stout dry air at the surface most of this rain is not making it to the surface. We will continue to see a few sprinkles over the next couple hours. A warm front will be lifting through the area tonight lowering ceilings and brining widespread rain. Some of the high res guidance also suggests some embedded thunder with the most likely impacted terminals being BRD/HYR. Rain will begin clearing out tomorrow morning but we may see some lingering fog through the morning hours.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
Issued at 407 PM CDT Sun May 19 2024

Breezy southwest winds are expected to persist from Grand Portage to Grand Marais for the next few hours this afternoon.
Then, winds transition to northeasterly for Monday with speeds around 10-15 kt. Winds become stronger from the northeast on Tuesday with gusts 25-30 kt, increasing to around 35 kt Tuesday afternoon and night. Headlines will likely be needed through Wednesday afternoon/evening as gusty winds persist as low pressure passes through. We will see rain later tonight through Monday, then again Tuesday through Wednesday. There may be thunderstorms Tuesday into Wednesday, and some stronger storms can't be ruled out.

For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt.

DLH WATCHES/WARNINGS/ADVISORIES
MN...None.
WI...None.
MARINE...Small Craft Advisory until 9 PM CDT this evening for LSZ140.

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