980
FXUS63 KDLH 221630
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1130 AM CDT Sun Sep 22 2024

.KEY MESSAGES...

- Frost expected tonight through sunrise Monday morning for many
  locations across the Northland inland from Lake Superior.

- Cooler weather today through Tuesday, then widespread high
  temperatures in the 70s return for mid-week into next weekend

- Very little to no rain (less than 15% chances) through the
  upcoming week.

&&

.DISCUSSION...
Issued at 256 AM CDT Sun Sep 22 2024

Current Conditions - Today:

A cold front that moved through the Northland on Saturday has
now shifted east of the area, with winds having shifted to the
northwest under clearing skies, though some stratus clouds will
linger in NW WI for a few more hours. Some gustier katabatic
winds continue through early morning along the North Shore, with
gusts up to 25-35 mph as cooler air funnels down the terrain
and river valleys of the North Shore. These winds should
gradually subside on Sunday morning.

Broad high pressure slides into the Upper Midwest today,
leading to mainly sunny skies across the majority of the
Northland, as well as a cooler and drier airmass. High
temperatures will be around normal, topping out in the low to
upper 60s. Some daytime wind gusts up to 15 to 20 mph are
expected, but will drop off and become light this evening and
calm tonight as the center of the high pressure moves directly
overhead.

Frost Tonight through Sunrise Monday:

Calm winds, dry air, and clear skies will lead to a favorable
setup for efficient radiational cooling tonight, which should
allow low temperatures to plummet into the mid to upper 30s
across most of the Northland locations inland from Lake Superior
tonight into early Monday morning. Some of the typical colder
spots in the Iron Range and interior Arrowhead could touch the
low 30s and see low temperatures around freezing, as well. Given
this temperature forecast, a Frost Advisory has been issued for
2 AM - 8 AM on Monday morning.

Also can`t rule out some very patchy frost in the Iron Range,
inland Cook County, and parts of NW WI on Monday night, but the
low temperature signal isn`t quite as cold as it is for tonight
into early Monday morning.

Quiet Workweek Forecast:

The weather pattern for the rest of the week remains relatively
benign, with a predominately dry forecast (precipitation chances
less than 15%) until next weekend at the earliest.

An upper-level shortwave trough over the coast of British
Columbia this morning will travel east across the Canadian
Prairies later today and Monday before diving southeast across
the Dakotas/Minnesota late Monday and Tuesday. This system will
not have access to Gulf of Mexico moisture and the moisture it
will have (PWATs of 0.7-0.8", near the average value for late
September) does not look sufficient to produce any rainfall in
the Northland Monday night into Tuesday due to a layer of dry
air from the surface up to 750mb. This system will keep high
temperatures on Monday and Tuesday mild in the mid-60s to
low-70s, however.

Global ensembles are in good agreement in a broader upper-level
ridge moving over the central CONUS for the mid-week into next
weekend timeframe, albeit with some slight variations in
amplitude and location of the ridge`s axis. Regardless, this
pattern will push widespread high temperatures back into the
mid-upper 70s for the Northland for Wednesday into next weekend,
though overall humidity levels will remain lower than what we
saw this last week. There is a lower confidence scenario for
next weekend where a weak shortwave trough or two rounds the
northern portion of the upper-level ridge, in which case the
Northland could be grazed by light rain, but precipitation
chances are still only 15-20% at this point as most global
ensemble members keep next weekend dry.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 1130 AM CDT Sun Sep 22 2024

VFR conditions are expected through the TAF period. Some gusty
northwest winds should calm this afternoon and evening become calm
overnight. Expect light southerly winds tomorrow.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 256 AM CDT Sun Sep 22 2024

Northwesterly winds around 20 knots and waves of 2 to 4 feet
continue through early this morning in the Apostle Islands.
Additionally, wind gusts up to 25 to 30 knots persist along the
nearshore waters of the North Shore north of Silver Bay due to
some katabatic winds as cooler air funnels down the higher
terrain and river valleys of the North Shore. Grand Marais has
been consistently gusting to around 30 knots since 11 PM because
of this. A Small Craft Advisory is in effect for the
aforementioned locations until 9 AM CDT this morning. Winds
remain northwesterly but calm to 5 to 15 knots, with occasional
gusts to 15-20 knots today before becoming light out of the
north this evening and tonight. No significant weather or winds
expected through mid week.

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

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Frost Advisory from 2 AM to 8 AM CDT Monday for MNZ010>012-
     018>021-026-035>038.
WI...Frost Advisory from 2 AM to 8 AM CDT Monday for WIZ001>004-
     006>009.
MARINE...None.

&&

$$

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