116
FXUS63 KDLH 082347
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
647 PM CDT Sat Jun 8 2024

.KEY MESSAGES...

- Widely scattered showers and thunderstorms will be around this
  afternoon and evening. A few storms could contain gusty winds
  of 25 to 35 mph.

- Quiet and dry weather expected Sunday and Monday. Patchy frost
  is possible (40-60% chance) in the eastern interior Arrowhead
  and inland north-central Wisconsin (southern Ashland and Iron
  and northern Price Counties) late Sunday night into early
  Monday morning, but a freeze is not likely (>95% chance above
  freezing in those locations).

- Periodic shower and thunderstorm chances Tuesday and beyond
  with temperatures warming up. A few strong thunderstorms are
  possible (15% chance) in north-central Minnesota later
  Wednesday.

&&

.DISCUSSION...
Issued at 215 PM CDT Sat Jun 8 2024

Upper-level low pressure located over northwest Ontario is
keeping breezy northwest flow over the Northland today and
ushering in some mid-level moisture which has formed into widely
scattered rain showers this afternoon. The high-based (6-8 kft
above ground level) and very limited-available moisture in
these showers will keep any rainfall amounts to less than 0.2
inches within very localized spots of the Northland through the
sunset hours today. High res forecast model soundings support
the satellite observations showing shower-top growth to 15-20
kft allowing a few cloud-to-cloud lightning flashes so far. An
isolated cloud-to-ground lightning strike cannot be ruled out
though through 8-9 PM though today. As thunderstorm chances peak
in the 4-7 PM time period today, weak thunderstorm updrafts hold
a potential to collapse in and create highly localized gusty,
erratic wind gusts to 40 mph this evening. Pea size hail cannot
be ruled out either, but those localized erratic wind gusts are
much more likely in this environment today.

As the low pressure moves further eastward overnight, a backdoor
cold front drops southward into the Borderlands first Sunday
early morning and continues towards the central and southern
Northland locations into the later morning hours creating mostly
cloudy skies under a deck of low clouds and seasonably cooler
daytime temperatures.

Surface high pressure moves into the region from the northeast
Sunday evening and overnight under a mid-level ridge coming into
the forecast area from the US Northern Plains. Idealized
radiational cooling conditions are forecast for inland
north-central Wisconsin (southern Ashland, southern Iron and
northern Price Counties) by early Monday morning to allow patchy
frost to form. The weather grids in those areas contain patchy
frost references currently and an Advisory for frost cannot
be entirely ruled out over coming forecast packages if
confidence on low temperatures Monday morning of 35-36 F (60%
chance of occurrence) persist. The other location for frost
potential (40% chance) is the eastern interior part of the
Arrowhead along the Gunflint Trail in northern Cook County.
There is a 95% chance of temperatures being above 32 F for
those patchy frost potential locations Sunday night reaching
only 35-36 F.

Quiet weather Monday sets up under very dry air aloft so the
forecast remains on the drier side for the relative humidity
forecast with blending in some lower (10th percentile of all
guidance) into the dewpoint temperatures.

As the mid-level continues to amplify as it shifts eastward
later Monday, southerly flow develops over the Upper Midwest
with a low pressure centered in the southern Canadian Plains
dragging a cold front across the Northern Plains Monday night.
Moisture and frontal forcing enters the Northland from west to
east Tuesday morning to create chances (50-70%) for widespread
rainfall of a tenth to a half-inch in northeast Minnesota and
slightly lesser amounts into northwest Wisconsin throughout
Tuesday daytime. There is very little support for much more than
general isolated thunderstorms in northwest Wisconsin Tuesday
so severe weather is not expected Tuesday.

An upper-level jet streak and a mid-level vort max rotating
through mean westerly flow on Wednesday coincide with a
corridor of 500-1000 J/kg of CAPE and bulk shear of 50-55 knots
as precipitable water values approach 1.1-1.2 inches, per
ensemble forecast guidance, in northwest Minnesota and
approaching north-central Minnesota. Due to this setup, there is
about a 15% chance of strong thunderstorms in Brainerd Lakes
northward into Koochiching County Wednesday evening. Right now
the primary hazards would appear to be wind gusts to 50 mph and
small hail, but near-severe hazard potential could build with
about a 50 mile shift eastward in this corridor of best storm
ingredients over the next few days. Depending on the evolution
of the later Wednesday storm chances, there are also periodic
chances of storms for the eastern Northland Thursday and into
Friday as temperatures warm into the upper-70s areawide and
around-80 inland.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 647 PM CDT Sat Jun 8 2024

Scattered showers with isolated thunderstorms are currently
occurring across a large portion of the region early this evening.
Gusty winds and multiple outflow boundaries are expected from these
showers and storms over the next few hours as they collapse from a
loss of diurnal heating. Ceilings will remain VFR through tonight,
as cloud bases remain elevated from deep mixing earlier today and
skies become mostly clear tonight. MVFR ceilings are expected to
develop Sunday morning and continue until the afternoon in the wake
of a cold frontal passage. Winds will be remaining from the
northwest to north through the TAF period.

&&

.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 215 PM CDT Sat Jun 8 2024

Isolated general thunderstorms may produce wind gusts to 30
knots this afternoon and evening before dissipating after
sunset. Quiet weather with west to northwest winds 10 to 15
knots Sunday becoming easterly around 10 knots Monday.

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...None.

&&

$$

DISCUSSION...NLy
AVIATION...Unruh
MARINE...NLy