Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 271727
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1127 AM CST Tue Feb 27 2024

.KEY MESSAGES...

- Heavy snow is expected this morning through early afternoon in
  Koochiching and far northern St. Louis Counties. Lighter snow
  is expected elsewhere.

- A cold front will bring gusty winds and cold temperatures
  tonight into Wednesday.

- A return to springtime warm temperatures is expected later
  this week, into this weekend, and early next week.

&&

.DISCUSSION...
Issued at 351 AM CST Tue Feb 27 2024

The main focus for today revolves around heavy snow expected
across far northern Minnesota, particularly Koochiching and far
northern St. Louis counties. Strong mid-level frontogenesis has
revealed itself as heavy snow falling over parts of eastern
North Dakota into northwest Minnesota. A distinct single band
has yet to develop, with more broad and loosely organized areas
of heavier snow falling at this hour over the Grand Forks area.
Models are in good agreement about focusing an area of higher
snowfall rates associated with frontogenesis into Koochiching
county through this morning, and if anything, short-range model
guidance has continued to tick slightly upward with QPF amounts.
At this time there is high confidence in amounts of 6 inches or
more (~80%), with some totals locally as high as 10 inches
certainly possible. Potential for riming, which could lower snow
amounts some, looks a bit less favorable this morning as
temperatures aloft are expected to continue cooling steadily
with the onset of snow and cold air advection. Certainly SLRs
will likely be lower at the first onset of snow, but fairly
quickly becoming higher as the thermal column cools. The snow
growth layer aloft will be somewhat limited due to steep lapse
rates, but the steep lapse rates will also promote higher
snowfall rates. All factors considered, potential remains high
for heavy snowfall rates around 1 inch per hour for about 6 to 7
hours starting around 6 AM and ending around 1 PM. Locally
higher rates approaching 2 inches per hour are not out of the
question. As the main axis of frontogenesis exits to the
northeast this afternoon, snow will become much lighter and end
later this afternoon across northern Minnesota. A Winter Storm
Warning is in effect through this afternoon for Koochiching
County, and Winter Weather Advisories are in effect for northern
St. Louis and northern Itasca counties.

Away from the heavy snow band, a strong cold front will blast
through today into this evening from northwest to southeast.
With this, some broad light snow is expected, though with the
air mass expected to be pretty dry behind the front and lift
being generally focused on areas of mid-level frontogenesis,
most areas are not expected to see much in the way of snowfall
accumulations. Up to an inch is expected for most in northeast
Minnesota outside of Koochiching, northern St. Louis, and
northern Itasca counties. A redeveloping band of frontogenesis
is expected this afternoon over northwest Wisconsin, so some
locally higher amounts are possible there. A little enhancement
due to a topographically-forced gravity wave may bring totals up
to around 2 inches along the Bayfield Peninsula. Additionally,
lingering lake-effect in northern Iron county may result in
localized totals up to 5 inches. Overall amounts in northwest
Wisconsin have been trending slightly downward with dry air
expected to make its way in fairly quickly behind the cold front
tonight.

Gusty winds and cold air are also expected to accompany this
cold front. North to northwest winds gusting up to around 35
mph are expected for most places, except higher gusts to 45 mph
along the North Shore due to downslope flow. This will lead to
some blowing snow and lower visibilities for areas that see
sufficient snow to blow around. The cold air moving in will
result in low temperatures falling into the single digits above
and below zero tonight with wind chill values from the teens to
low 30s below zero. The coldest wind chills of 25 to nearly 35
below are expected from the Arrowhead (especially inland) and
west across the Iron Range and Canadian Border. Wind Chill
Advisories will likely be needed tonight, but we will wait to
post any such headlines until this afternoon`s forecast update
after the heaviest snow moves out of northern Minnesota.

Any lingering snow Wednesday morning should be limited mainly to
Iron county. Sunshine is expected, albeit with cold daytime
highs in the single digits and teens. Blustery winds will keep
wind chills in the single digits above and below zero through
the afternoon.

Strong warm air advection and ridging is expected to develop
going into Thursday. This will signal a return to above average
springtime temperatures. The jetstream and associated weather
systems are likely to remain in Canada through Friday. There are
some hints at a possible warm frontal precipitation band on
Saturday into Sunday, which could mean some rain or slushy snow
for some areas. Can`t completely write off some convective
potential somewhere around Sunday into Monday as well, though
we`re still pretty far out to guarantee that. Overall, the
pattern looks warm.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1121 AM CST Tue Feb 27 2024

Large range of conditions across the area with heavy snow over
INL and MVFR to clear skies elsewhere. LIFR conditions at INL
with heavy snow should gradually improve through the afternoon
with snow coming to an end early this evening. HIB and DLH may
receive some light snow that quickly passes through this
afternoon, knocking visibility down to MVFR levels for an hour
or two. Similarly, some snow will develop over HYR for a couple
hours late this afternoon and into the evening. VFR conditions
should return to all terminals through the second half of the
TAF period. Strong northwest winds will continue to increase
this afternoon and remain strong overnight, strongest at DLH
where occasional gusts of 30-35 knots are possible this evening
into early Wednesday morning. Winds will remain strong but come
down slightly into Wednesday.

&&

.MARINE...
Issued at 351 AM CST Tue Feb 27 2024

Expect north to northwest winds to continue intensifying today
as a cold front passes through. Small Craft Advisories go into
effect late this morning, then Gale Warnings for much of the
North Shore and outer Apostle Islands this afternoon through
tonight. Confidence has decreased (~50% chance) that gusts will
reach gales over the outer Apostles, but we will maintain the
Gale Warning for now as gusts are expected to reach 30 knots and
some 35 knot gusts certainly can`t be ruled out tonight. Heavy
freezing spray is also expected tonight into Wednesday with cold
air moving in along with the gusty winds. Winds are expected to
gradually decrease Wednesday afternoon and evening. Winds will
become more southerly going into Thursday with gusts remaining
below 20 knots.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Storm Warning until 6 PM CST this evening for MNZ010.
     Winter Weather Advisory until 6 PM CST this evening for MNZ011-
     018.
WI...Winter Weather Advisory from 6 PM this evening to 6 AM CST
     Wednesday for WIZ004.
MARINE...Small Craft Advisory until 11 PM CST Wednesday for LSZ121-
     143>148.
     Small Craft Advisory until 2 PM CST this afternoon for
     LSZ140>142-150.
     Gale Warning until 6 AM CST Wednesday for LSZ140>142-150.
     Heavy Freezing Spray Warning from 6 PM this evening to 4 PM
     CST Wednesday for LSZ145>148-150.

&&

$$

DISCUSSION...JDS
AVIATION...Levens
MARINE...JDS


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