Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 152342

Area Forecast Discussion
National Weather Service Duluth MN
542 PM CST Wed Nov 15 2017

.SHORT TERM...(This evening through Thursday)
Issued at 302 PM CST Wed Nov 15 2017

Colder air will settle across the Northland this evening and
overnight, which will support slick road conditions, especially on
secondary and untreated roadways. Strong cold air advection behind a
cold front that swept through the Northland earlier today will bring
in below freezing temperatures across the area. 925 mb temperatures
are progged to quickly fall into the 5 to 10 below zero range by 06z
tonight, only decreasing from there through Thursday morning.
Observed road temperatures across Minnesota are hovering around the
lower to middle 30s, so temperatures don`t have to drop far to allow
freezing precipitation on road surfaces. NAM and RAP model soundings
indicate there will be very little in the way of saturation in the
ice producing layer, so thinking that the predominant precipitation
type will be freezing drizzle as there is a shallow saturated layer
in the low-levels, although some light snow is possible over the
Minnesota Arrowhead. Overnight lows tonight should drop into the
lower to middle teens along the International Border into the lower
20s over northwest Wisconsin. Thanks to the colder air and
northwesterly flow off Lake Superior, there should also be some
light snow accumulation from the Bayfield Peninsula southeast over
north-central Wisconsin. The heaviest snowfall amounts should fall
along the Gogebic Range in Iron county, with new snow amounts
between 1" to 2" possible.

Thursday will be a drier day, with colder temperatures compared to
the last few days. Highs Thursday should range from the middle to
upper 20s over the Minnesota Arrowhead to the lower 30s over the
south. The only things of note for Thursday are winds turning more
on-shore/northeasterly in the morning, which some models are
progging some light precipitation from Duluth and points northeast
along the North Shore. However, it looks too dry in the 1000-850 mb
layer to support any lake effect showers. The better support for
precipitation will come in the afternoon and evening as 850-700 mb
layer warm air advection will bring increasing clouds and some small
chances of snow showers. Also, enhanced moisture advection will
increase precipitation chances Thursday night into Friday.
Southeasterly winds will also intensify in the afternoon due to a
tightening sfc pressure gradient, with gusts between 20 to 25 kts,
especially across our western counties.

.LONG TERM...(Thursday night through Wednesday)
Issued at 302 PM CST Wed Nov 15 2017

An area of low pressure will move through the central Canadian
Plains Thursday night and Friday. This will be accompanied by a mid
level trof and pieces of vorticity in the southwest flow aloft. There
will be enough warm air ahead of this system and its cold front to
result in a mix of winter p-types Thursday night, possibly
becoming all rain over the southern tier of the forecast area. The
mixed p-types will continue Friday morning before becoming all
rain over the south and a rain/snow mix over the north. Some
freezing drizzle/freezing rain is also possible over the higher
terrain of northeastern Minnesota. Some light snow accumulations
may occur along the Canadian border, especially Friday. The mixed
p-types will continue Friday night as the low moves east and
another area of low pressure moves from Iowa into the lower Great
Lakes by Saturday afternoon. Enough cold air is pulled into the
region Saturday afternoon to change the p-type to all snow. The
snow will also diminish over all but the elevated terrain of
northwest Wisconsin. High pressure moves over the region Saturday
night and Sunday. However, lake effect processes will persist
along the south shore of Lake Superior. A quasi-zonal flow aloft
with ridging at the surface will be in charge Sunday night and
Monday. Warm, dry air will be pulled into the area through Monday.
By Monday night, a strong area of low pressure will move through
the Canadian Plains and drag a cold front through the region. It
will take some time for enough moisture to saturate the atmosphere
and produce pcpn, but the cold air surging into the area will
lead to snow for the main ptype through Tuesday.


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 539 PM CST Wed Nov 15 2017

Low pressure will move off to the east across the region tonight,
as high pressure moves in from the west. Some of the clouds will
break up as the night wears on, although stubborn areas of clouds
will persist through the night and into Thursday. Another area of
low pressure will approach the region from the west on Thursday.
Strong WAA ahead of this system will bring an increase in mid and
high level clouds. IFR/MVFR conditions overnight will transition
to a mix of MVFR/VFR on Thursday.


DLH  19  30  28  37 /  10  20  30  60
INL  14  28  27  35 /  10  20  40  60
BRD  21  33  31  40 /   0  10  10  20
HYR  23  33  31  38 /  20  10  30  70
ASX  26  33  30  40 /  50  20  30  70


LS...Small Craft Advisory until 4 AM CST Thursday for LSZ121-140-146-

     Small Craft Advisory until noon CST Thursday for LSZ148.



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