Sunrise 5:56 AM   Sunset 8:15 PM Moonrise 11:47 PM   Moonset 6:31 AM

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LSZ148 /o.exp.kdlh.ma.w.0035.000000t0000z-231005t2345z/ 641 Pm Cdt Thu Oct 5 2023
.the special marine warning will expire at 645 pm cdt - .
the affected areas were - . 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 - .
the showers have weakened and no longer pose a significant threat to boaters. A gale warning remains in effect for this area until 12 am cdt tonight.
lat - .lon 4673 9060 4674 9068 4687 9063 4695 9044 4713 9035 4714 9013 4672 9040 time - .mot - .loc 2340z 265deg 35kt 4710 9010 4694 9019 4679 9044

LSZ100
No data

FXUS63 KDLH 272024 AFDDLH

Area Forecast Discussion National Weather Service Duluth MN 324 PM CDT Sat Apr 27 2024

KEY MESSAGES

- Another low pressure system will bring widespread rain Sunday through Monday. Very minor and localized accumulations of freezing rain may be possible along the higher terrain of the North Shore (20-40% chance).

- Strong northeast winds gusting up to 40-45 mph are expected Sunday afternoon through Monday morning along the North Shore. There is a low chance (20-30%) for lakeshore flooding along Lake Superior's shorelines due to strong winds and high waves.

- Another rainy system is likely (60-70%) Tuesday into Tuesday night. There may be more rain later in the week.

DISCUSSION
Issued at 324 PM CDT Sat Apr 27 2024

Rain continues this afternoon, mainly along and east of the US-53 corridor. As low pressure continues moving northeast this afternoon, the rain is expected to end along with it with perhaps some lingering sprinkles into the evening.

An extended break between low pressure systems is expected tonight and into Sunday morning. Models continue to slow down the arrival of the next low pressure system on Sunday, bringing the next round of rainfall in sometime around mid-day into the afternoon. As such, we can expect lingering clouds tonight with mainly dry weather. Despite there being plenty of low-level moisture, fog is not generally expected as winds should remain strong enough to keep the lower- atmosphere well mixed. The air aloft is expected to be dry enough such that any breaks in the low-level clouds could bring some brief patches of clearing.

As low pressure eventually moves northward on Sunday, a broad swath of warm air advection-driven rain will overspread the region. The previous system brought rainfall amounts anywhere from around a quarter of an inch to an inch, and this was well within the forecast amounts. For this second round, model ensembles continue to be in pretty good agreement on rainfall amounts that will be similar, albeit perhaps a touch higher than the first round. By and large, amounts hovering around 1" are expected. Flooding threats will be very minimal due to the long duration of the rain. Also, convection potential will be minimal, similar to the last system. Model soundings all suggest a deep inversion near the surface, so if there are any bubbles of a few hundred J/kg of elevated CAPE that develop, there could possibly be a few embedded rumbles of thunder, but this is expected to be the exception rather than the rule. The rain should persist into Monday, then gradually start to let up through Monday afternoon and evening.

Now, for the folks who thought winter was over, we have some new news for you! That's right, a chance (albeit somewhat small; ~30-40%) for freezing rain for parts of the higher terrain along the North Shore. The HRRR and other ensembles have hinted at just enough orographic cooling to result in temperatures falling a degree or two below freezing Sunday night into early Monday morning while rain falls to result in this freezing rain threat.
Now, a degree or two of temperature will make all the difference in whether or not this happens at all. Models favor only the higher terrain of the North Shore to see below or around freezing temperatures, not directly along the shoreline.
Therefore, if any freezing rain does occur, it should be pretty isolated. Areas from Two Harbors to Silver Bay and northeast along the high terrain will be the target areas. NBM probabilities for a glaze of ice approach 30-50% mainly around the tip of the Arrowhead with probabilities diminishing further southeast. Even where any freezing rain falls, accumulations are likely to be quite minimal with temperatures starting out warm and only falling to a degree or two below freezing for a ~6-8 hour period late Sunday night into early Monday morning. We will continue to monitor this freezing rain potential, but right now the risk for hazardous weather overall appears small.

Strong northeast winds are expected to accompany the rain Sunday afternoon through Monday morning. There's still a bit of spread in ensembles for maximum wind gusts, but in general, the highest winds and gusts can be expected along the North Shore of Lake Superior and extending into the Twin Ports. Wind gusts around 40 mph are expected frequently for areas within about 20 miles of the North Shore shoreline, and NBM probabilities of gusts of 45 mph or higher vary from 70-90%. As such, confidence is high enough with this forecast update to issue a wind advisory along the North Shore. It'll be blustery out there, so hold on to your umbrellas tightly!

With these strong winds, we must also assess the possibility for lakeshore flooding. From previous research, lakeshore flooding has occurred in the Duluth area when the water level is at around 603' (hovering between around 601.5' to 602.0' the past couple days).
Previous cases also featured sustained winds 22-30 kt, gusts 30-39 kt, and northeast flow duration around 24 hours or more. Wave heights around 12-16 feet are usually a minimum for lakeshore flooding. With this guidance in mind, the current forecast features winds/gusts in that low-end threshold for a duration about 20-24 hours and wave heights in the 8-13 ft range (higher towards Silver Bay, and closer to the lower end around the Twin Ports). With all this in mind, confidence isn't quite high enough to issue a Lakeshore Flood Watch at this time. While some lakeshore flooding can't be ruled out, mainly around the Twin Ports, confidence is only 20-30% at this time. We will continue to monitor the potential for lakeshore flooding in upcoming updates, and if confidence increases to 50% or greater, we may toss out a watch so stay tuned for updates.

Another rain-making system is likely (60-70% chance) Tuesday into Tuesday night. The originating track of this one will be from Montana/Dakotas, and as such, it'll have a bit less moisture to work with. So, we'll be looking at a 6-12 hour period of rain with amounts more likely to hover around a quarter to half an inch.
Convective potential may be a smidge higher with this system, however, with several models hinting at some instability stretching up towards northwest Wisconsin Tuesday evening. It's too early to determine any potential hazards, but we'll continue to monitor the possibility for some thunderstorms with this Tuesday system.

Models become more divergent for the later part of the week, but rain chances (20-40%) may continue in the later part of the week with an amplified pattern aloft likely to persist.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
Issued at 1233 PM CDT Sat Apr 27 2024

MVFR ceilings are expected to be common through the period as one low pressure system departs this afternoon and another one arrives on Sunday. There is a slight possibility (20-30% chance)
that some VFR conditions could happen briefly tonight as there may be some patches of clearing amongst the low clouds. In the next 2-4 hours, visibility will be mostly VFR but occasionally MVFR as showers continue to pass through. The general trend will be for showers to end and visibility to improve as low pressure departs. Visibility is expected to remain VFR tonight through Sunday morning after rain moves away. Breezy conditions this afternoon, but winds briefly become light tonight, switching direction from northwesterly to northeasterly ahead of the next low pressure system. Direction will be more variable this afternoon at HYR closer to the low pressure center. Breezy conditions redevelop Sunday morning along with rain chances returning (30-50% chance) late Sunday morning from south to north.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
Issued at 324 PM CDT Sat Apr 27 2024

Winds will continue to weaken this evening as low pressure departs. Waves up to 2-3 ft may still linger a bit into the early evening before they weaken as well.

Attention then turns to another low pressure system that will arrive mid-day to afternoon on Sunday, bringing rain and very strong northeasterly winds. Winds will start to strengthen with gusts to 25 kt late tonight, then gales are expected starting Sunday morning around the Twin Ports, then extending elsewhere Sunday afternoon. Winds will be strongest Sunday night into Monday morning, then decreasing as the low pressure system passes through Monday afternoon. This is expected to be a high- end gale event with gusts to 40 to 45 knots, highest along the North Shore Monday morning. In addition, wave heights around 8 to 14 ft are expected, especially along the North Shore and Outer Apostle Islands. Breezy conditions and high wave heights will persist into Monday night.

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

DLH WATCHES/WARNINGS/ADVISORIES
MN...Wind Advisory from 4 PM Sunday to 4 PM CDT Monday for MNZ020- 021.
Wind Advisory from 4 PM Sunday to 10 AM CDT Monday for MNZ037.
WI...None.
MARINE...Small Craft Advisory from 4 AM Sunday to 4 PM CDT Monday for LSZ121-148.
Small Craft Advisory until 4 PM CDT this afternoon for LSZ140>147-150.
Small Craft Advisory from 4 AM to 4 PM CDT Sunday for LSZ140>143-146-147-150.
Gale Warning from 4 PM Sunday to 4 PM CDT Monday for LSZ140>143-146-147-150.
Small Craft Advisory from 4 AM to 10 AM CDT Sunday for LSZ144- 145.
Gale Warning from 10 AM Sunday to 10 AM CDT Monday for LSZ144- 145.

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