Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 271200
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
600 AM CST Mon Feb 27 2017

.SHORT TERM...(Today through Tuesday)
Issued at 449 AM CST Mon Feb 27 2017

At 4 AM, a band of light snow showers stretched from near Park
Falls through Hayward to Danbury, north of a stationary front
positioned across central Minnesota. Light snow was reported at
Hinckley, Siren, Rush City, and Mora in the past two hours. A few
stronger radar echoes were also noted from McGregor to near
Cloquet, but nearby AWOS sites have not reported snow. Think there
may be some flurries with this band, which may move into the Twin
Ports by 6 AM. With mainly clear skies up north, radiational
cooling has driven temperatures below zero. The coldest readings
we`ve seen thus far were -8 degrees Fahrenheit at Ely and Crane
Lake. Some of our cooperative observer sites will likely have
temperatures in the teens below zero this morning.

The light snow showers will continue through mid-morning as
isentropic upglide over the frontal surface and a surge of warm
air, and associated frontogenesis, pushes eastward. Think the snow
showers will clear northwest Wisconsin by 10 AM. Snow
accumulation this morning of a dusting up to a few tenths of an
inch are possible. A few breaks in the clouds may develop as they
lift north. 850-500 mb layer relative humidity values decrease as
the first area of ascent shifts east. Clouds will generally spread
northward with the Northland experience partly to mostly cloudy
skies for much of the afternoon. A weak shortwave trough and
associated area of DCVA will push into northern Minnesota this
afternoon, which may generate enough ascent for a few snow
showers. Otherwise, with the front lifting north across the
forecast area today, think temperatures will trend warmer.
Carrying highs today in the upper 20s along the International
Border with readings near 40 degrees in my southern zones.
Depending on the timing and amount of clearing over the south, and
the strength of the warm air advection near the surface,
temperatures in my southern zones may climb even warmer than
currently forecast. Nudged temperatures toward the ECAM/CONSRAW
blends. While the BCCONSRAW seemed too warm, added a fraction of
that blend to raise temps in the south another few degrees.

Attention then shifts to a storm system forecast to move through
the Northland tonight through late Tuesday night. A mid-level
trough of low pressure will move from the Intermountain West this
morning across the Rockies and the Plains on Tuesday. With
southwest and southerly flow over the Southern and Central Plains,
one might expect to find a pool of available Pacific and Gulf
moisture ahead of the approaching trough. That is not the case
this morning. A very dry airmass stretches from northern Mexico
into the Plains, leaving only a ribbon of northern Pacific
moisture available over the Northern Plains and Canadian Prairies.
Lee cyclogenesis is expected this afternoon over northeast
Colorado, but with meager moisture available, the low will deepen
slowly as it lifts into the Central Plains. Isentropic upglide
ahead of the approaching low should be sufficient for snow showers
to develop over eastern South Dakota and quickly expand northeast
into the Northland tonight. Snow will continue and intensify over
northern Minnesota early Tuesday morning, and a rain/freezing
rain/snow mix is possible generally south of a line from Brainerd
to Aitkin to Hayward to Ashland. As southerly winds and warm air
advection strengthens over Pine County and northwest Wisconsin,
the mixed precipitation line is expected to lift northward,
potentially as far north as the Twin Ports. Inland areas of
northwest Wisconsin may see a period of light rain during the day.

While there is still some uncertainty in the amounts, the
heaviest precipitation is expected to fall Tuesday morning from
Aitkin and Grand Rapids northeast to the Twin Ports, Ely, and
Silver Bay. As a result, there is a potential for a swath of 3 to
6 inches of snow from this system. Due to the wide variety of
deterministic and ensemble model solutions, questions about
moisture availability and forcing for ascent, along with
precipitation type challenges, have decided not to issue headlines
this morning.

.LONG TERM...(Tuesday night through Sunday)
Issued at 449 AM CST Mon Feb 27 2017

Light snow or a mix of rain and snow will continue early Tuesday
evening becoming all snow before diminishing for most areas
overnight as the low pressure system pulls away from the region.
The chance for snow will continue along portions of the South
Shore as northerly winds develop and colder temperatures move
across the lake. Additional snowfall Tuesday night will range from
a few tenths of an inch to 2 inches, mainly from the North Shore
to the Twin Ports and into far northern Wisconsin.

Several shortwaves will affect portions of the Northland
Wednesday into Thursday as the upper flow transitions to
northwesterly. A shortwave on Wednesday will mainly affect
portions of our southwestern CWA from the Walker area toward Pine
City. At this time, we will carry either some small POPs or
flurries. Lake effect snow will continue to be possible along
portions of the South Shore but lack of deeper moisture should
prohibit significant snowfall.

Another shortwave will dive southeast through the Northern Plains
Wednesday night but its current track would keep any snow out of
the Northland. However, there will continue to be a chance for
lake effect snow Wednesday night into Thursday in the snowbelt
region of the South Shore. Low level instability will be greater
as colder air moves over Lake Superior and there will be a window
where there is deeper moisture present which could lead to a few
inches of snow Wednesday night/Thursday morning, mainly in the
snowbelt of eastern Ashland and northern Iron counties.

High pressure will move into the Red River Valley by early
Thursday evening and continue east Thursday night bringing a dry
period to most of the Northland. As the high shifts east on
Friday, increasing warm air advection may lead to some light
precipitation in spots. A surface low pressure system will then
track along or north of the International Border, depending on the
model, dragging a weakening frontal boundary into the area
Saturday with it stalling across central/southern portions of
Minnesota and Wisconsin. There will be a chance for mainly light
mixed precipitation Friday through Sunday over parts of the area.

Highs Wednesday will range from 20 to 25 over far northern
Minnesota to around 30 from the Brainerd Lakes region to Hayward
and Phillips. Temperatures will be a couple degrees cooler
Thursday before they start to warm Friday into Saturday. Highs
Saturday will range from 35 to 40 far north to the lower to middle
forties in the Brainerd Lakes region into northwest Wisconsin.
Highs temperatures will drop a couple degrees on Sunday for most
areas.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 600 AM CST Mon Feb 27 2017

A stationary front stretched from South Dakota through central
Minnesota into central Wisconsin early this morning. The front
will move a bit further north today as warm front as an inverted
trough noses into western Minnesota by early evening. There may be
some some light snow over portions northwest Wisconsin and
northern Minnesota early this morning with a period of MVFR
conditions. There will be a chance for more light snow later this
afternoon over far northern Minnesota with mainly VFR conditions.

Tonight, the low pressure system will move into the region along
with increasing FGEN and a shortwave aloft. All these features
will cause precipitation to expand. Mainly snow will occur over
much of northern Minnesota with a mix of rain, snow, or freezing
rain over northwest Wisconsin. Conditions will lower to IFR for
most areas tonight.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  33  25  34  15 /  10  70  70  50
INL  28  13  26   3 /  20  50  30  10
BRD  41  27  34  17 /  10  60  60  30
HYR  41  32  40  21 /  30  60  70  50
ASX  40  31  37  21 /  10  60  70  60

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&

$$

SHORT TERM...Huyck
LONG TERM...Melde
AVIATION...Melde



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