Sunrise 5:45 AM   Sunset 8:31 PM Moonrise 3:41 AM   Moonset 4:44 PM

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FXUS63 KDLH 052039 AFDDLH

Area Forecast Discussion National Weather Service Duluth MN 339 PM CDT Sun May 5 2024

KEY MESSAGES

- Elevated fire weather conditions Monday with breezy southeast winds and 30-40 percent relative humidity.

- A round of showers and thunderstorms moves northeast into the Northland from Monday night through Tuesday evening. Rain amounts of around an inch or less expected. Severe weather is unlikely.

- Light shower chances linger into Wednesday and Thursday. A few embedded thunderstorms are possible Wednesday afternoon and evening across far southern portions of the Northland.

DISCUSSION
Issued at 340 PM CDT Sun May 5 2024

Rest of Today - Monday:

Mostly sunny to partly cloudy skies are occurring across the Northland due to some fair-weather cumulus. Light winds are also ongoing as high pressure dominates the Upper Midwest.
Temperatures are very pleasant today, topping out in the mid-60s later this afternoon.

Winds turn calm tonight under mainly clear skies with low temperatures in the mid-30s to mid-40s.

We see a shortwave ridge move over the Northland on Monday on the backside of the departing high pressure to our east and ahead of a deepening low pressure system moving into the Northern Plains. As a result, the Northland will remain precipitation-free until at least Monday night, but the increasing pressure gradient will lead to gusty southeast winds.
Due to a delay in moisture advecting into the area, elevated fire weather conditions will develop on Monday as the gusty winds combine with minimum relative humidity values dipping into the 30-40% range for areas away from Lake Superior. These same areas will also see high temperatures climb into the mid-60s to low-70s. Meanwhile, locations near Lake-Superior will be relegated to highs in the mid-50s due to winds off of the lake.

Monday Night - Tuesday Evening:

Moisture advection (PWATs increasing to 1-1.25 inches)begins in earnest ahead of the approaching low-pressure system/warm front Monday evening in response to a 40-50 knot low-level jet (850 mb). Showers and thunderstorms move into the Brainerd Lakes beginning Monday night ahead of and along the warm front, with precipitation spreading northeast into the Northland through much of Tuesday before ending by Tuesday night. Some instability (SBCAPE around 100-400 J/kg) is forecast for Tuesday afternoon into evening from the Brainerd Lakes into NW WI, which will be the best window of time for scattered thunderstorm development.
0-6 km bulk shear vectors will be on the weaker side (15-25 knots) with marginal mid-level lapse rates but decent low-level lapse rates. Therefore, severe weather is not anticipated, but a few of these storms could produce small hail (pea-size) and brief thunderstorm gusts to 30-40 mph.

Rainfall forecast for Monday night through Tuesday evening hasn't shifted slightly down relative to previous forecasts.
The current amounts are expected to range from one-third of an inch to around one inch. The highest of these amounts are expected in east-central MN to the North Shore and into NW WI.
That said, any locations that see thunderstorms move overhead could see amounts locally exceed one inch.

Wednesday - Thursday:

The upper-level low over the Northern Plains lingers into Wednesday before opening up into a trough as it dives southeast into the mid-Mississippi and Ohio River Valleys on Thursday into Thursday night. Lighter rain showers linger in the Northland on Wednesday into Thursday, with perhaps an embedded thunderstorm or two across far southern portions of the Northland on Wednesday afternoon into early evening. No severe weather is expected with these storms.

Late Friday - Next Weekend:

Another low pressure system dives southward out of Manitoba into the western Great Lakes for Friday PM into parts of next weekend, leading to additional rain potential during this timeframe. Still some spread in model guidance regarding the exact track and duration of this system for the weekend, so have kept PoPs in the 15-30% range for now.



AVIATION /18Z TAFS THROUGH 18Z MONDAY/
Issued at 1238 PM CDT Sun May 5 2024

VFR conditions will persist throughout the TAF period. Scattered to pockets of broken fair weather cumulus with bases at 5-6 kft will continue through the afternoon before dissipating early this evening with the loss of daytime heating. Winds remain generally less than 10 knots until Monday morning, with southeast winds gusting to around 20 knots for many terminals near the end of the TAF period as the pressure gradient increases ahead of an approaching low. Winds turn stronger after the end of the current TAF period Monday afternoon into Monday night out of the east with precipitation chances returning as early as Monday night in central MN.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/
Issued at 340 PM CDT Sun May 5 2024

Winds remain light at or below 15 knots tonight into early Monday morning, starting southwesterly and shifting to easterly later tonight.

Winds strengthen out of the east to northeast on Monday as the pressure gradient increase between high pressure departing to our east and low pressure moving into the Northern Plains to our west. Conditions will become hazardous to small craft on Monday from Port Wing to the Twin Ports and north to Silver Bay. Winds become even stronger Monday night into Tuesday, with the hazardous conditions expected to develop for most of western Lake Superior on Tuesday. There is also a 40-60 percent chance for a few gale force gusts at times late Tuesday morning into mid-Tuesday afternoon from Two Harbors to Grand Marais, as well.
Winds weaken Tuesday night.

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 from 7 AM Tuesday to 1 AM CDT Wednesday for LSZ140-147-150.
Small Craft Advisory from 4 AM Tuesday to 1 AM CDT Wednesday for LSZ141-142.
Small Craft Advisory from 3 PM Monday to 1 AM CDT Wednesday for LSZ143>146.
Small Craft Advisory from 10 AM to 4 PM CDT Tuesday for LSZ148.

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