Latest Duluth Area Text Forecast Discussion product from NWS:
823
FXUS63 KDLH 181138
AFDDLH
Area Forecast Discussion
National Weather Service Duluth MN
638 AM CDT Wed Mar 18 2026
.KEY MESSAGES...
- Areas of light freezing drizzle mainly along and west of the
US-53 corridor may create slippery stretches on area roads
through this morning. Sidewalks may also become slippery.
Freezing drizzle will taper off late this morning into early
afternoon.
- Another round of light precipitation is forecast this
afternoon and tonight. Precip is expected to start as rain
before changing to snow. There may be a period of light
freezing rain over portions of northwest Wisconsin tonight.
Ice accumulations will be less than a tenth of an inch. Snow
totals will be less than half an inch.
- Warming conditions begin today with daytime highs rising above
freezing into the 40s and 50s through the rest of the week.
- A better organized clipper will move through the region over
the weekend. Mixed precipitation is forecast.
&&
.DISCUSSION...
Issued at 417 AM CDT Wed Mar 18 2026
As of 3 AM...
The Northland is under a southwest to northeast oriented
baroclinic zone (an area in the atmosphere featuring a "notable"
horizontal temperature gradient) at the surface and aloft
located to the northeast of a quasi-stationary front over the
eastern Dakotas. Westerly winds aloft were providing a broad
area of isentropic ascent over much of Minnesota. An upper-level
trough extended from around 925 mb to 700 mb and was
responsible for most of the light snow overnight. The trough
axis was over the Minnesota Arrowhead to northeast Illinois at
08Z and will continue to propagate east. The low stratus over
the region in the wake of the snow was largely the result of the
isentropic ascent mentioned earlier. Thermal profiles reveal a
relatively deep cloud layer which appears to top out around 700
mb over northwest Wisconsin tapering down to around 850 mb near
Brainerd and International Falls. The dry air aloft will
continue to erode the clouds from top down. As that occurs warm
air advection aloft and decreasing cloud top heights will
support a chance from snow to freezing drizzle. Between 1 and 3
AM ASOS stations at Brainerd, Duluth, and Park Rapids reported
ice accumulation accompanied by cloud bases below 1000ft and
visibility between 3 and 6 miles. GOES-East night microphysics
RGB reveals mainly liquid water cloud tops west of a line from
Pine City to Bigfork to Baudette. Areas east of the line are a
little fuzzier with a possible mix of liquid droplets and ice
crystals. Observations across the area varied between "mist" and
light snow.
Early this morning...
The latest RAP forecasts indicate the isentropic ascent will
persist through this morning with stratus lingering. We expanded
the coverage of light and very light freezing drizzle with this
forecast package based on trends, model forecasts, and
observations. While the ASOS ice accumulation sensors help
confirm the existence of freezing drizzle when other data
support the occurrence, it`s this forecaster`s subjective
opinion the actual values reported are unreliable. Even so, with
persistent light to very light freezing drizzle, there is a
potential for slippery roads for the morning commute. We will
monitor trends and road conditions. A short-term Winter Weather
Advisory for freezing drizzle may become necessary if
indications of ice accumulation persist over portions of central
and north-central Minnesota.
Rest of today and tonight...
Temperatures will warm above freezing today into this evening
as warm air advection continues. The afore mentioned baroclinic
zone will remain over the region while a upper-level jet streak
and area of 500 mb vorticity propagate southeastward into
Minnesota by tonight. Freezing drizzle will gradually taper off
from southwest to northeast this morning. It may linger into the
early afternoon over the Arrowhead. The approaching speed max
aloft will provide another boost to isentropic ascent and a
diffuse area of frontogenesis. Most deterministic and high-res
model guidance features an area of precipitation over north-
central Minnesota which will advance into northwest Wisconsin
this evening. It`s not easy to piece together the various
dynamic contributions to that precipitation chance. Subtle
height falls, confluent flow in the 850 to 700 mb layer, a
diffuse area of frontogenesis, and a transient zone of omega
will all play a part. Temperatures will start out above freezing
leading to a period of rain as precipitation begins. Later this
evening and overnight in northwest Wisconsin there may be a
period of freezing rain with accumulation between 5 hundredths
and a tenth of an inch. The main question will be how quickly
road temperatures cool after sunset. As of this forecast the
potential for 5 hundredths of an inch of freezing rain over
northwest Wisconsin is less than 20%. Rain will eventually
change to snow before ending over northeast Minnesota with less
than half an inch of snow expected.
Thursday through Friday night...
The broad upper-level pattern will remain unchanged for the
remainder of the work week. A large blocking high over the
southwest US will remain in place with a ridge over the western
US. Northwest flow will persist over the northern Plains and the
Canadian Prairies into the western Great Lakes. Weak and
persistent warm air advection will continue allowing
temperatures to warm into the upper 30s to middle 40s Thursday
and low 40s to middle 50s on Friday. Another shortwave trough
will propagate through the northwest flow Thursday night and
early Friday morning. Model guidance reveals an area of mixed
precipitation over Ontario to the central Great Lakes during
that time. Portions of the Arrowhead have a chance of a
rain/snow mix as that system passes by.
With the warm air advection and temperatures climbing well
above freezing during the day, there is a potential for
widespread dense fog to develop as early as Thursday evening.
Once the fog develops, it will be hard to shake until the
pattern changes. Dense Fog Advisories will likely be needed
later this week. Another complicating factor on temperatures
will be the presence of the fog. The warm air advection alone
doesn`t appear strong enough to raise temperatures 10 degrees
from Thursday into Friday. If the fog develops and persists,
temperatures may be 10 degrees cooler than forecast for Friday.
Saturday into next week...
A pattern shift is forecast for the weekend into next week. The
blocking high over the southwest US will weaken and an upper-
level trough is forecast to propagate through the northern US
and southern Canada. Details vary depending on which model we
consider. Overall there is a chance for widespread precipitation
possibly as early as Saturday morning. The warmer temperatures
will remain in place at the start which will give a mix of rain
and snow. A few inches of snow to shovelable or plowable amounts
are possible. If precipitation begins Saturday and changes to
snow Saturday night, look for higher totals. If precipitation
doesn`t arrive until Sunday morning, lower totals are likely.
The fast-moving clipper will be short-lived with drier and
warmer conditions returning for Monday and Tuesday. A few
shortwave troughs may pass over the Northland Monday night
through Wednesday. Each one would bring a chance of
precipitation, likely a mix of rain and snow.
&&
.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 638 AM CDT Wed Mar 18 2026
Low IFR to MVFR stratus persists early this morning across the
region. Patchy freezing drizzle has been observed underneath this
stratus and will continue on and off until temperatures rise above
freezing by the afternoon. There are indications of improvement to
MVFR and even some VFR in north-central Minnesota around midday. A
second round of wintry precipitation arrives late this afternoon
into tonight, bringing conditions back down to IFR and potentially
LIFR. KHYR will have the best chance of seeing freezing rain/drizzle
tonight leading to a glaze of ice, with a rain/snow mix for the
other TAF locations.
&&
.MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/...
Issued at 417 AM CDT Wed Mar 18 2026
Strong southerly winds will weaken and veer westerly this
morning. Small Craft Advisory remains in effect for Grand Marais
to Grand Portage. Waves of 3 to 6 feet early today will subside
to 1 to 3 feet by this afternoon. The next period of hazardous
conditions will develop this weekend as a more organized low
pressure system moves through the region.
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...Small Craft Advisory until 4 PM CDT this afternoon for LSZ140.
&&
$$
DISCUSSION...Huyck
AVIATION...Unruh
MARINE...Huyck
NWS DLH Office Area Forecast Discussion
