Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 231741

Area Forecast Discussion
National Weather Service Duluth MN
1141 AM CST Mon Jan 23 2017

.SHORT TERM...(Today through Tuesday)
Issued at 313 AM CST Mon Jan 23 2017

A little bit of a repeat this morning from yesterday morning as
light precipitation along and north of the Mesabi Range and south
towards the Brainerd Lakes was ongoing and some patchy/areas of fog
around the Northland, with some locally dense fog. This
precipitation is associated with the remnants of a mid-level
shortwave that has plagued the area for the last few days due to its
slow movement. There may be some light snow accumulations across
northern St. Louis county as the returns on radar are pretty much
stationary. Only up to one-half of an inch or so is expected before
ending by day break. There could still be some slick spots on
untreated roadways in this area.

The wave should depart the region later this morning before another
shortwave moves in. Not expecting much in the way of precipitation
accumulation as the latest RAP/GFS/NAM model soundings all indicate
rather shallow moisture profiles. There could still be some
drizzle/freezing drizzle and snow with this system, with only small
chances expected over the MN Arrowhead region. A slight drop in
temperatures are forecast as the shortwave departs this evening,
enhancing cold air advection. Lows tonight in the lower to mid 20s
are expected.

There will be a brief respite from precipitation Tuesday morning
before a potential winter storm moves into the region Tuesday
afternoon and evening. A 140+ kt 250 mb jet streak translates
across the Four-Corners Region and eventually places the
Northland in the left exit region of the jet, indicating more
robust lift. An associated 500 mb shortwave with good isentropic
lift, with values between -5 and -10 ubar/s, will eventually
arrive in the region Tuesday afternoon, so PoPs should be on the
increase during this time. There`s still some uncertainty
regarding onset of precipitation and the precipitation types as
there may be some rain/snow mix before transitioning to all snow
later Tuesday afternoon as colder air is ingested into the system.
The GEFS ensembles support this late afternoon timing for the
Hayward area, with snow beginning later in the day from Duluth and
points northward as the system moves northward. More details
on this system in the long term forecast section below.

.LONG TERM...(Tuesday night through Sunday)
Issued at 313 AM CST Mon Jan 23 2017

Forecast focus in the extended will be on a winter storm that will
impact portions of the Northland Tuesday night into Wednesday.

An upper level trough will cover much of the western half of the
country Tuesday evening with a shortwave in the Central Plains. A
surface low is forecast to be centered in the Central/Southern
Plains area, depending on the model. The ECMWF and Canadian are
further south with the low compared to the NAM/GFS. The low will
move northeast Tuesday night and the NAM/GFS bring it into southern
Wisconsin then continue it northeast with the NAM quite a bit faster
than the GFS. The Canadian/ECMWF have a track a bit further south
but with similar timing to the GFS. These differences in the track
lead to significant differences in potential snowfall amounts across
the region. The GFS/NAM have higher snowfall further north into the
Northland. Confidence in one particular solution is lower than
average so we used a blended approach and increased the chance for
snow and amounts, especially over most of northwest Wisconsin.
Additional adjustments will occur over the next 24 hours. Snow,
which may be mixed with rain in spots early, will move north and
east Tuesday night with chances highest over northwest Wisconsin.
The snow will then diminish in coverage/intensity through Wednesday
afternoon/evening for most areas. Several inches of snow are
possible across northwest Wisconsin Tuesday night through Wednesday
afternoon, tapering to less than an inch over far northern
Minnesota. Keep in mind, if the further northerly track of the storm
occurs, snow amounts will need to be increased across much of the
area. Stay tuned for updates on this developing storm system.

After this low moves through, colder air will be moving into the
region and will lead to additional light snow/flurries Wednesday
night into Thursday. Lake effect snow will be possible along
portions of the South Shore through much of the rest of the week
possibly leading to significant additional snowfall in the snowbelt
region of Ashland/Iron Counties.

Highs Wednesday will still be from 30 to 35 for most areas, dropping
to 25 to 30 on Thursday then remaining in the 20`s for the remainder
of the week.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1141 AM CST Mon Jan 23 2017

Widespread MVFR/IFR ceilings expected through the forecast. There
will be periods of BR, especially at HIB/HYR, with vsbys dropping
into the IFR/LIFR, even VLIFR at HYR from 02Z to 15Z.


DLH  35  26  34  28 /  20  10  20  50
INL  34  22  32  23 /  30  10  10  20
BRD  33  25  34  26 /  10  10  30  60
HYR  36  26  37  29 /  10  10  30  70
ASX  38  28  37  29 /  10  10  10  70




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