Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 170810
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
310 AM CDT Fri Mar 17 2017

.SHORT TERM...(Today through Saturday)
Issued at 310 AM CDT Fri Mar 17 2017

The Northland will continue to see a wintry mixture of
precipitation this morning, bringing accumulating snowfall to
parts of the northern and eastern forecast area, followed by a
periods of freezing drizzle and drizzle in the wake of the snow.
The main band of precipitation, over the northern and eastern
forecast area, is the result of a deeply saturated atmosphere
ahead of a shortwave trough moving through the Northland. The
shortwave trough is associated with a surface low in southern
Manitoba, which will move into northwest Ontario today. For the
most part, the precipitation early this morning is snow, which
will bring accumulations of about up to a few inches for parts of
the Minnesota Iron Range and Arrowhead, as well as parts of
northwest Wisconsin. However, the upper-levels will dry in the
wake of the precipitation, cutting off the supply of ice crystal
seeding needed to safely secure the production of snow. The
shallower saturated layer could produce freezing drizzle across
much of the Northland, resulting in a light glaze of icing. There
will then likely be a transition to drizzle and light rain by this
afternoon, mainly across far northern Minnesota. Gusty west-
northwesterly flow will develop this afternoon in the wake of the
surface low`s passing trough, and cooler air will begin to filter
into the Northland. The precipitation will begin to taper off late
this afternoon through tonight, and there will likely be a
transition from drizzle and light rain to snow, followed by
freezing drizzle again later tonight.

A surface ridge will shift into the Northland from the west
Saturday, resulting in weakening winds and increasing sunshine.

.LONG TERM...(Saturday night through Thursday)
Issued at 310 AM CDT Fri Mar 17 2017

Mild with a chance for light precipitation late this weekend
before cooler, near-seasonable temperatures settle in mid to late
week. Dry early in the week, then an increasing chance for
precipitation late- week. Cooler temperatures will likely mean a
mix of rain and snow possible, but while some models (particularly
the ECMWF) depict a pattern which brings the potential for heavy
precipitation rates (mainly rain), this seems like a less likely
scenario due to a stubborn area of high pressure over northern
Ontario and convection firing across the mid and lower Mississippi
River Valley limiting the potential for deep moisture to reach
the Northland.

On the synoptic scale another warm front builds across the upper
Midwest Saturday night into Sunday resulting in warming
temperatures and increasing clouds. This warm front is associated
with a low developing across the central to northern Canadian
Prairie region, unlike the precipitation ongoing this morning
which is related to a low taking a clipper-like track from
southern Manitoba towards the Great Lakes. Model guidance has
trended northward with this developing low late in the weekend,
and because of this the overall large-scale forcing and column
moisture associated with the warm frontal zone is now expected to
be much weaker than previously forecast. While the broad lift
induced by the area of low level warm air advection will probably
lead to some light precipitation, this could be a case where by
the time the column starts to saturate the broad lift along the
warm frontal zone has exited the region. Sky cover forecast for
Sunday may be a bit pessimistic depending on timing of the front.
Highs approaching the mid to upper 50s for parts of north-central
and east-central Minnesota, perhaps a run at 60 at Brainerd if
skies end up being more sunny than currently forecast.

Late Sunday a cold front moves from west to east across the upper
Midwest with a northwest flow pattern developing into mid-week as
high pressure builds across the region. This area of high
pressure will become centered over western Lake Superior on
Wednesday, with seasonably temperatures and mainly sunny skies
expected to prevail through the first half of the week.

A pattern change late week as a mid to upper level longwave
trough develops over the west coast with an upper level ridge over
the Midwest. This pattern is typically conducive for
precipitation across the upper Midwest as mid-level shortwave
troughs eject out of the Rockies into the Great Plains. While this
pattern would also result in warmer temperatures developing under
the ridge, the progressive flow pattern means there will not be
enough time to advect a significantly warmer and more moist
airmass into the region. ECMWF remains the most aggressive with a
"panhandle hook"- type set-up developing, while the GFS and GEM
remain on the light side due to lows taking a more southerly
track. Still, most solutions lead to increasing precipitation
chances Thursday into next weekend with temperatures remaining
near-seasonable with highs in the mid 30s to low 40s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1214 AM CDT Fri Mar 17 2017

A band of rain, snow, sleet, and even freezing rain is moving
slowly across the terminals. Locations under the band have
IFR/MVFR conditions in -rasnpl for the most part, and should
continue for several hours. Precipitation should shift northeast
of the area after 15z, but expect that ceilings will remain
MVFR/IFR through the end of TAF period for most terminals, and
some locations may have poor visibilities until 18z, possibly with
drizzle. West winds to increase after 16z with sustained speeds
around 15 kts and gusts to 20-25kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  39  25  37  24 /  70  20   0   0
INL  37  19  34  24 /  80  50   0  10
BRD  41  23  42  28 /  10   0   0   0
HYR  40  27  40  22 /  40  30   0   0
ASX  41  28  38  22 /  80  30  10   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Winter Weather Advisory until 9 AM CDT this morning for MNZ011-
     012-019>021.

LS...None.
&&

$$

SHORT TERM...Grochocinski
LONG TERM...JJM
AVIATION...LE



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