Area Forecast Discussion Issued by NWS Duluth, MN
000
FXUS63 KDLH 181154
AFDDLH
Area Forecast Discussion
National Weather Service Duluth MN
654 AM CDT Mon Mar 18 2024
.KEY MESSAGES...
- Snow showers and flurries will taper off this morning. Up to
another inch of snow is forecast for northern Iron County with
lower totals elsewhere.
- Near-critical fire weather conditions are possible on a daily
basis into the middle of this week due to low humidities and
breezy winds.
- A clipper will bring a chance of snow to the Northland
Thursday and early Friday morning. There is a 50 percent
chance of at least an inch of snow south of US-2 in Minnesota
and over all of northwest Wisconsin. There is a 60 percent
chance of at least 2 inches of snow south of a line from Pine
River to Sandstone to Hayward to Park Falls.
- There will be another chance of snow late next weekend into
early next week
&&
.DISCUSSION...
Issued at 415 AM CDT Mon Mar 18 2024
Cold air advection aloft and cyclonic flow will allow flurries
and snow showers, including lake-effect snow showers, to
persist through late this morning. Drier air evident on GOES-
East satellite imagery over northwest Ontario and northwest
Minnesota as of 09Z will continue to advance slowly southward.
Look for the flurries and snow showers to taper off as skies
clear. Low-level winds will back westerly from west to east
this morning into the afternoon as warm air advection arrives
from the west. The change in wind direction and warming temps
will bring an end to lake-effect snow showers. Isentropic ascent
nosing into a zone of 850-700 mb frontogenesis will generate
some radar returns this afternoon over southeast Manitoba,
northwest and north- central Minnesota, and northwest Ontario.
Think the odds of precipitation reaching the surface with a very
dry sub-cloud layer is low, so opted for flurries this
afternoon initially. Forcing gets a little better as the frontal
zone moves into the Arrowhead and northwest Wisconsin, thus
included a chance of light snow for those areas. Temperatures
today will trend a little warmer than Sunday with highs in the
upper 20s to middle 30s.
A pair of cool fronts will propagate southeastward across the
region tonight and Tuesday pendant from a weak surface low which
will traverse Ontario. Flurries and light snow showers are
forecast over northeast Minnesota and portions of northwest
Wisconsin in the wake of the fronts. Cold air advection at the
surface will result in steep lapse rates. Winds will veer
northwesterly starting tonight with gusts of 15 to 30 mph
forecast. Winds remain strong Tuesday and gradually weaken
Wednesday. Highs on Tuesday will reach the low 30s in north-
central Minnesota and the low 40s in the St. Croix Valley.
Stronger cold air advection will develop Tuesday night and
Wednesday with temperature dipping well below normal. Highs
midweek will be in the teens in the Arrowhead to the upper 20s
over central Minnesota into northwest Wisconsin. Lake-effect
snow showers will be possible over Bayfield, Ashland, and Iron
counties. Upstream moisture will be somewhat limited, so we`re
not expecting much accumulation from the lake-effect snow
showers Tuesday night and Wednesday.
Another clipper system will move across the Plains and into the
Midwest Thursday and Friday. Northward moisture transport over
Kansas, Nebraska, and Iowa will support a swath of light rain
and snow as that system passes over the region. For the
Northland, we will see mainly snow with the system. As of this
morning there is a 50 percent chance of at least an inch of snow
south of US-2 in Minnesota and over all of northwest Wisconsin.
There`s at least a 60 percent chance of at least 2 inches of
snow from Pine River to Sandstone to Hayward to Park Falls. With
the fast propagation of the system, there will likely be a
sharp gradient in snow amounts. A narrow band of frontogenesis
oriented roughly west-northwest to south-southeast across
central Minnesota into southern Wisconsin will accompany the
system. The precise location of that feature will determine
where the heaviest snow will fall. There have been both north
and southward shifts with the band of snow over the past several
days and additional fluctuations are expected.
The fleeting sampler pack of winter weather will continue over
the weekend into early next week. There are indications of a
more impactful system passing over the Plains and Midwest
Saturday through Monday. That system may produce a swath of
heavy snow somewhere in the region. As of this morning, the best
chances of 4 or more inches of snow are south of the Northland.
Anyone with travel plans this weekend into early next week is
encouraged to keep up with the forecast as the details are
likely to change.
&&
.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 655 AM CDT Mon Mar 18 2024
MVFR ceilings have been slow to erode so far this morning. Low-
level clearing indicated by surface obs and GOES-East imagery
stretched from west-central MN to northwest ON. Tracking the
clearing would have it arrive at HIB and BRD around 19Z and DLH
a bit later than that. Therefore delayed the clearing a bit with
this update. Think the downslope flow along the North Shore
will scatter out the clouds at times at DLH prior to 19Z. HIB
dipped to 5 mile visibility for a few minutes between 1030Z and
1100Z. Think there will be occasional visibility reductions
there as winds back to 310 by 15Z. Winds back southwesterly
through early afternoon at all the terminals and become gusty
late this afternoon and this evening. Low-level wind shear will
be a concern at BRD as warmer air arrives aloft. Surface to 2
kft vector differences are less than 30 knots elsewhere. If wind
speeds aloft trend a little stronger, wind shear may be needed
at INL, HIB, and DLH.
A cold front will propagate southward past INL, HIB, BRD, and
DLH before 19.12Z. There appears to be enough moisture and
forcing for ascent for flurries and light snow showers behind
the front. Winds will veer northwesterly behind the front.
&&
.MARINE...
Issued at 415 AM CDT Mon Mar 18 2024
Gusty north and northwest winds will gradually diminish and
back southwesterly this morning. Wind speeds and gusts will
increase again this afternoon and become hazardous to small
craft once again. A weak clipper system will move southeastward
across the region tonight and Tuesday and will be accompanied by
a cold front which will veer winds northwesterly. Wind speeds
will increase to 15 to 25 knots with gusts 25 to 35 knots. Gales
of 35 to 45 knots are possible over the North Shore waters
Tuesday night into early Wednesday morning. Conditions will
likely remain hazardous for smaller vessels until early Thursday
morning.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...Winter Weather Advisory until noon CDT today for WIZ004.
MARINE...Small Craft Advisory until 10 AM CDT this morning for LSZ121-
140>148-150.
&&
$$
DISCUSSION...Huyck
AVIATION...Huyck
MARINE...Huyck