888
FXUS63 KDLH 110949
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
449 AM CDT Sat May 11 2024

.KEY MESSAGES...

- Chilly through early morning, with Frost Advisories in
  portions of the Arrowhead and north-central MN.

- Warm this weekend with a chance for rain showers today into
  tonight and then some afternoon thunderstorm chances (20-40%)
  Sunday in NW WI.

- A few of the Sunday afternoon storms becoming strong in NW
  WI. Primary hazards would be wind gusts to 50 mph and penny
  size hail.

- Very dry afternoon relative humidity expected today and
  especially on Sunday, particularly across NE MN.

&&

.DISCUSSION...
Issued at 449 AM CDT Sat May 11 2024

Early this Morning:

Aside from a few mid-level clouds in the Arrowhead this morning,
skies remain clear across the Northland. This, combined with
light winds, has allowed for another efficient radiational
cooling setup leading to some isolated pockets of patchy fog in
areas that saw rain yesterday. Additionally, temperatures have
dropped into the low to mid 30s across the interior Arrowhead
and far north-central MN, where Frost Advisories are in effect.
Pockets of mid-30s are also expected for portions of NW WI, but
these aren`t expected to result in more than some patchy frost
in the coldest locations.

Today:

We see northwest flow some weak shortwave ridging sets up for
today, resulting in high temperatures warming into the 60s to
low/mid 70s, warmest across north-central MN. Northeast MN
should also see the development of a narrow band of light rain
showers later this morning into the afternoon, though deep
mixing to 750 mb and drier low levels should keep most of this
precipitation from hitting the ground. As a result, only expect
a few hundredths of an inch of rain at best with the showers.

Otherwise, the deeper mixing today will lead to lower relative
humidity values this afternoon dropping to around 25-35% for
most of the Northland, though some values down to 20% will be
possible in north-central MN. Winds will be weaker than
yesterday, turning southwesterly during the afternoon with gusts
up to 15 to 18 mph. The strongest gust are also expected in the
region of lowest humidity, so near-critical fire weather
conditions are expected for north-central MN. Relative humidity
will quickly increase this evening.

This evening - Sunday:

A closed upper-level low/associated surface low treks across
northern Manitoba and Ontario from this afternoon through
Sunday. This system will bring scattered showers and a few non-
severe storms southeastwards across the Northland this evening
and tonight ahead of a progressive cold front. Rainfall amounts
look light, with spottier amounts of 0.05-0.2". Some locations
will not see any rain since precipitation will not be
widespread.

By Sunday afternoon, some redevelopment of showers and
thunderstorms is likely in the warm sector just south of the
front. Higher-res model guidance has been trending faster with
the southeastward progression of the cold front Sunday
afternoon, so the window of space and time for the redevelopment
of thunderstorms in NW WI before the front pushes south of our
forecast area is relegated to a 2 PM - 5 PM window at best. Most
of this higher-res model guidance actually develops storms just
south of our southern tier of NW WI counties. The FV3 and RAP
are slightly slower with the front progression, and would give
areas southeast of a Siren to Hayward to Hurley line a 20-40%
chance to see some brief, scattered thunderstorms. If this
slower solution were to occur, warm sector SBCAPE of 500-1200
J/kg, steep low- and mid-level lapse rates, and deep layer shear
vectors of 25-35 knots would be sufficient to produce a few
strong storms with wind gusts up to 50 mph and up to penny size
hail, and localized rainfall amounts of 0.1-0.3". However, a
faster moving front would have any storms develop south of our
area.

Another concern on Sunday will be much drier air advecting in
behind the cold front, particularly across northeast MN where
deep mixing will be taking place. High temperatures in the 70s,
relative humidities dropping into the upper-teens to mid-20s,
and breezy northwest winds will likely lead to near-critical
fire weather conditions and possibly Red Flag Warning criteria
for north-central and Northeast MN. Relative humidity values for
Sunday afternoon have been trending lower, though the wind/gust
forecast has been trending ever-so-slightly weaker to 15 to 20
mph for most of north-central and northeast MN, but some
locations near the International Border are still forecast to
see wind gusts up to 25 mph.

Next Week:

High pressure moves into the Upper Midwest for Monday and
Tuesday, leading to mainly sunny skies and drier conditions.
Slightly cooler temperatures in the 60s (even cooler near Lake
Superior) should keep afternoon relative humidities from getting
too low and wind gusts will be generally under 20 mph, as well.
Parts of the Arrowhead and NW WI may even need some Frost
Advisories Monday and Tuesday nights due to temperatures dipping
into the mid-30s.

Ensembles point to shortwave troughing Wednesday-Thursday and
more shortwaves late next week into next weekend bringing
periodic shower and thunderstorm chances with them. Still
looking at 40-60% chances for >0.25" of rain with the midweek
system, with a 20-40% chance for greater than 0.5". High temperatures
remain mostly in the 60s during this timeframe, as well.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1254 AM CDT Sat May 11 2024

Shower activity has ended across the Northland, with
predominately VFR conditions through the TAF period. There still
remains a 10-20% chance for patchy fog to develop later
overnight into the early morning hours today for terminals that
saw rainfall yesterday, but these chances were too low to
include in the TAFs.

Light and variable winds tonight back to westerly in the
morning for most (northwesterly for KHYR), then to southwesterly
during the afternoon and southerly this coming evening. Winds
remain generally light, though a few gusts to 10 to 15 knots are
possible during the peak mixing in the afternoon to early
evening.

A few showers will be possible over far northern and northeast
Minnesota late this morning into afternoon, with an additional
round of scattered showers and a few embedded thunderstorms
moving northwest to southeast across the Northland this evening
and Saturday night associated with an approaching cold front.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 449 AM CDT Sat May 11 2024

Southwesterly winds this morning turn southerly this afternoon
with gusts up to around 15-18 knots. Some stronger gusts to 20
knots develop very near land along the South Shore Saturday
night. Additionally, some showers and isolated thunderstorms are
expected Saturday night.

Winds turn northwesterly on Sunday, with warmer temperatures
leading to most of the stronger winds remaining over land. Some
gusts to 20 knots are possible along the North Shore Sunday
afternoon into evening, however. As of now, Small Craft
Advisory-level winds are not expected for Sunday afternoon.
Northeasterly winds develop for Monday and Tuesday, with some
funneling into the Twin Ports pushing afternoon gusts up to
around 20 knots.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Frost Advisory until 8 AM CDT this morning for MNZ010>012-018-
     019-026.
WI...None.
MARINE...None.

&&

$$

DISCUSSION...Rothstein
AVIATION...Rothstein
MARINE...Rothstein