Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 021201 AAA
AFDDLH

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
601 AM CST Fri Dec 2 2016

.UPDATE...
Issued at 601 AM CST Fri Dec 2 2016

Please see the updated Aviation Discussion below.

&&

.SHORT TERM...(Today through Saturday)
Issued at 407 AM CST Fri Dec 2 2016

The Northland remained between low pressure well off to the east
and weak high pressure over the Northern Plains. Plenty of low
level moisture remained under the inversion and will lead to
mostly cloudy skies today. There is a chance for a peek or two at
the sun in spots, but the majority of the region will remain
mostly cloudy. It`s possible some flurries or light freezing
drizzle could occur, but observations have not reported any
precipitation so far other than over portions of northwest
Wisconsin. There has been some lake effect precipitation in the
snow belt and KPBH briefly reported some light precipitation. We
will continue a chance for snow showers or patchy freezing drizzle
over portions of the snow belt, but we do not expect much
accumulation. A spotter in Gile at 105 am reported only 0.6 inches
of snow since 1030 am Thursday bringing the total to 2.4 inches.
The visibility at KIWD and webcams suggest little additional snow
has fallen since that report. Low level flow is forecast to back
through the day and become more westerly by this evening. Expect
highs today from the mid twenties to lower thirties.

Weak ridging will move into the Northland tonight and we expect
the clouds to stick around through the night. There could again be
some light freezing drizzle or flurries in spots but coverage
looks to be too limited to include at this time other than over a
small portion of northern Wisconsin. Lows tonight will range from
20 to 25...but there could be colder pockets should any brief
clearing occur.

The ridge will continue east on Saturday into Wisconsin. It
should remain mostly cloudy although there is a better chance for
a few peeks at the sun. Highs will range from the mid twenties to
around thirty.

.LONG TERM...(Saturday night through Thursday)
Issued at 407 AM CST Fri Dec 2 2016

Main concerns during the long term remain precipitation chances
and types with a late weekend system, the potential for several
rounds of precipitation Monday through Thursday, and cooler
temperatures.

Not much change to the going forecast this morning due to
continued low confidence in sensible weather details. A trough of
low pressure and area of surface low pressure will move across the
Dakotas Saturday night and Sunday. Southwesterly flow ahead of the
trough will advect a combination of Gulf and Pacific moisture into
the Northland. The long trajectories and precipitation forecast to
occur south of the area will limit the precip potential locally.
Maintained a chance of rain and snow showers Saturday night
through Sunday evening, with precip spreading from west to east
with time. Unseasonably mild conditions across the Plains and
Upper Midwest, and the lack of a robust reservoir of cold air to
tap, continues to play merry hob with max and min temps and
resultant precip types. Seems cold enough for all snow Saturday
night with a potential for rain advancing up the I-35 corridor
during the day. By mid- afternoon, the possibility of a rain/snow
mix will span from the Brainerd Lakes along and south of MN
Highway 210 to the Twin Ports and then across most of northwest
Wisconsin. Precipitation amounts with this disturbance appear
fairly low, generally less than 0.15 inches. There should be a
heat and moisture contribution from western Lake Superior, which
would enhance snow/rainfall amounts along the North Shore due to
southerly winds ahead of the low. Snow totals less than 2 inches
are expected with this system. There is also a potential for
freezing drizzle Saturday night, however this seems unlikely as of
this morning and have kept precip types simple.

A weak ridge of high pressure will slide east across the area
Sunday night and Monday morning bringing a brief reprieve from
precipitation. Another stout thermal inversion is likely with this
weak ridge, which would keep skies mainly cloudy with isolated
snow showers or pockets of freezing drizzle possible.

The next potential troublemaker is forecast to move into the
Northern Plains and Upper Midwest Monday afternoon and Monday
night. Deterministic models and GEFS members are clustered around
a similar track with the surface and low-level trough. Kinematic
details expose more variety in potential outcomes with the GFS
faster and stronger and the CMC slower and farther south. ECMWF is
in the middle of the pack by Monday evening. The GFS solution
would bring a quick-hitting burst of rain and snow showers to the
Northland Monday afternoon through Tuesday afternoon while the
ECMWF focuses the heaviest precipitation over the eastern Dakotas
into Manitoba. The CMC solution would yield the most precipitation
for our area with precip along the warm front Monday night, and
wrap around precipitation hitting my northwest zones Tuesday
afternoon and evening. Given the differences in the details,
maintained a consensus approach for now.

Beyond Tuesday night the differences in deterministic guidance
and ensemble members increase markedly. ECMWF winds up a strong
system and lifts it from the southern Mississippi Valley into the
eastern Great Lakes through Thursday night, with marginal
precipitation over the Northland from a cutoff low over the
Canadian Prairies. GFS has a similar solution but is faster with
the evolution and movement of the surface low and associated
shortwave trough. GEFS members are spread out from southern
Manitoba to the eastern Great Lakes. All of the solutions this
morning would yield some precipitation for the Northland between
Wednesday night and Friday. There is still a possibility the
system could actually track farther west than this morning`s
guidance suggests. Should a more westerly track emerge, precip
amounts and intensity would be much higher. For now, am content to
maintain a consensus blend until model consistency improves.

Temperatures will start the period slightly above normal and will
gradually cool through Friday to near to slightly below normal.
The most notable changes in the temperatures will be in the
daytime highs with readings 8 to 12 degrees below normal by
Friday. Overnight lows will remain near to slightly above normal
through the period.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 601 AM CST Fri Dec 2 2016

Went with a simple approach for this forecast. Low-level moisture
and continued cyclonic flow on the western periphery of departing
low pressure should keep mainly MVFR ceilings in place across the
region through Saturday morning. Have observed a few weak
streamers on radar early this morning which suggests there are a
few pockets of very light snow due to anthropogenic cloud seeding
in the vicinity of HIB to DLH. Other pockets of very light snow or
drizzle are likely throughout the day. Have maintained the earlier
forecast of VCSH at all sites. In the event a stray snow shower
visits one of the terminal, expect 8SM -SN at worst. 00Z and 06Z
NAM model profiles hint at the stratus scattering out this
afternoon at HIB, BRD, and possibly DLH. Meanwhile the past
several runs of the HRRR feature ceilings lower than presently
observed and continuing through the day. Overall think the
persistence forecast keeping overcast in the picture is the right
answer until we see some evidence of clearing. Confidence in this
forecast package is above average.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  30  24  29  24 /  10  10  10  30
INL  28  21  28  23 /  10  10  10  30
BRD  30  22  30  27 /  10  10  10  30
HYR  31  24  30  24 /  10  10  10  30
ASX  33  26  32  25 /  10  10  10  20

&&

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

$$

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



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