Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 130926
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
326 AM CST Mon Nov 13 2017

.SHORT TERM...(Today through Tuesday)
Issued at 326 AM CST Mon Nov 13 2017

A surface ridge extended through the Northland this morning but will
move east and south this morning with a southerly low level flow
developing and bringing in warmer temperatures. Aloft, zonal flow
will persist through tonight before winds back slightly ahead of an
approaching shortwave on Tuesday.

We expect another day of more clouds than sun for much of the area
with the best chance at some sunshine occurring this afternoon from
Walker to the Iron Range and points north. Expect highs in the
thirties.

Increasing warm air advection/isentropic lift tonight will lead to a
chance for drizzle or freezing drizzle over much of the area. We
increased chances a bit and later updates may need to do so further.
It`s possible a Winter Weather Advisory may be needed for parts of
the Northland as even a little freezing drizzle can lead to slick
roads. Temperatures will warm overnight so if the precipitation is
delayed some more drizzle than freezing drizzle could occur.

A shortwave and frontal boundary will move into the region on
Tuesday. There may be ongoing drizzle/freezing drizzle in the
morning with a chance for rain/drizzle in the afternoon as
temperatures warm into the upper thirties to lower forties.

.LONG TERM...(Tuesday night through Sunday)
Issued at 326 AM CST Mon Nov 13 2017

The relatively seasonal weather will continue for much of the week.
Light rain and drizzle is possible early in the period, and snow is
possible late this week. Colder air returns this weekend.

An area of low pressure will pass through Ontario Tuesday night and
Wednesday. An intrusion of relatively warm air into the Northland,
amidst the southerly flow ahead of the low`s approaching pre-frontal
trough, could be saturated enough to produce light rain and drizzle
Tuesday night, mostly over the eastern half of the forecast area.
The low`s cold front will sweep through the Northland early
Wednesday with a shortwave or upper low. Gusty winds will follow in
the wake of the cold front. The GFS suggests gusts could reach 25 to
30 mph, but held off forecasting winds this strong since cloud cover
could limit boundary layer mixing. Light snow is forecast over
northern MN and downwind of Lake Superior over northern WI because
of the cold air advection, large-scale forcing for ascent, and lake
enhancement from the cold flow over Lake Superior. There will be
little if any accumulation, though.

High pressure will move through the Northland later Wednesday
through Thursday, providing a period of drier weather. Our attention
then turns to what could be our highest impact weather of the week.
The models continue to indicate one or two areas of low pressure
will eject from the High Plains of the US and/or Canada into the
Upper Midwest and south-central Canada Thursday into Friday, and
likely strengthening and phasing into one strong low somewhere near
the Great Lakes. The moderate to strong large-scale forcing with
this system could drop moderate to heavy snowfall near the Great
Lakes region Friday into early Saturday, but there is still
considerable uncertainty as to how it will affect the Northland. If
anything, the latest model runs may be trending drier, or less
snowier, for the Northland compared to earlier runs. These latest
runs suggest the low may not sufficiently strengthen and slow down
until farther east into the Great Lakes region, lessening the
precipitation and snow to the Northland. There are also some
concerns with how much precipitation will fall as rain rather than
snow. For now, it`s safe to say there is a good chance parts of the
Northland will get some snow, and there is a low chance of heavy
snow greater than 6 inches.

Whether or not the Northland gets snow with this late week system,
we can expect a cool down in its wake. Another blast of Arctic air
will likely bring snow flurries and possibly light lake effect snow
to the Gogebic Range in northern Wisconsin.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1149 PM CST Sun Nov 12 2017

Stratus over KINL, KHIB and KDLH is expected to only slowly ooze
northeast for the next several hours, with only light south winds
and weak warm air advection aloft to help push it north from over
the terminals. Guidance has been overly optimistic with this
clearing trend and have gone with a more pessimistic trend through
approximately 14z, with a more rapid clearing trend after that.
Fog should develop for KBRD and KHYR again tonight, and possibly
also KDLH should the cloud cover ease north of it. Have some
prevailing MVFR with tempos for IFR where I have confidence it
will develop, though exact visibility is more uncertain. VFR
conditions should return to most sites by 16z today. Stratus
clouds are expected to stream back into the area from the south
after 00z, affecting KBRD, KINL, KHIB and KDLH by the end of the
TAF period. Confidence in timing is not very high but have put an
initial time and expect to adjust with later issuances.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  34  30  41  30 /   0  30  30  40
INL  35  27  41  27 /   0  10  10  20
BRD  38  32  43  29 /  10  20  20  10
HYR  37  30  42  31 /   0  30  30  50
ASX  38  31  43  34 /   0  30  20  50

&&

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

$$

SHORT TERM...Melde
LONG TERM...Grochocinski
AVIATION...LE



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