Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 171736
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1236 PM CDT Tue Apr 17 2018

.UPDATE...
Issued at 1234 PM CDT Tue Apr 17 2018

Updating Aviation section below for the 18Z TAF update.

&&

.SHORT TERM...(Today through Wednesday Night)

Issued at 326 AM CDT Tue Apr 17 2018

High pressure will bring mainly sunny skies to much of the
Northland today. Cool northerly flow over western Lake Superior
will keep clouds in the picture for northwest Wisconsin, along
with snow showers and flurries in the snowbelt.

Ridging will continue to build across the Northern Plains and
Upper Midwest today sandwiched between two upper lows, one over
the eastern Great Lakes and New England, and the other over the
southern Canadian Rockies. Surface high pressure and large-scale
subsidence will work to erode any lingering cirrus over much of
the Northland, while cool northerly flow keeps lake effect clouds,
snow showers, and flurries in play over northwest Wisconsin.
Additional accumulation in northern Iron County of up to 2 inches
is expected. Temperatures today will reach the middle 40s
northwest, but will linger in the middle 30s for the southeast.

The upper-level ridge flattens tonight as a lobe of vorticity and
associated shortwave trough scoot eastward into the Plains and
the Midwest. Surface low pressure is forecast to move east from
Colorado and southeast Wyoming into northern Missouri and southern
Iowa by sunrise Wednesday morning. Isentropic ascent and
deepening frontal circulations along the northern periphery of the
low will bring a wintry mix of rain and snow to portions of
Minnesota. Dry air advection from the north will pose a challenge
for precipitation in our southern zones. With the strongest
forcing well to our south, have nudged POPs a bit lower. The best
chance for rain and snow showers is mainly south of Minnesota
Highway 210 and over much of northwest Wisconsin. Snow
accumulation will be light, but melting and refreezing
precipitation may create slippery stretches of area roads
Wednesday night. Temperatures Wednesday will reach the middle 40s
in Koochiching County and the middle to upper 30s in the I-35
Corridor and over northwest Wisconsin. Lows Wednesday night will
dip into the middle to low 20s.

.LONG TERM...(Thursday through Monday)
Issued at 326 AM CDT Tue Apr 17 2018

A period of relatively quiet weather with warming temperatures
begins on Thursday, with a ridge of high pressure building into
the area during the day on Thursday along with an upper level
ridge building in as the upper low moves away from us over the
eastern Great Lakes region. This period should continue through at
least Friday night, with high temperatures Friday in the upper
40s to even mid 50s. Depending on the sunshine, we may get warmer
than that.

We have been watching the next large upper low that is expected
to cross the Rockies, and is currently tracking farther south than
the last couple upper lows to move across the CONUS, and will be
moving more slowly than the faster northern stream, which stays
well into Canada. Late Friday night it appears that we may catch
the fringes of of this storm, with a brief period of small pops as
that system brushes by. The warm temperatures continue into
Saturday and Sunday as well. The northern stream sends a shortwave
and cold front across the area Sunday night through Monday night,
with mainly the GFS bringing some small chance pops across the
area as it moves through the area. The ECMWF is dry, so have kept
pops small for now. The associated extra clouds and precipitation
depress temperatures for early next week, but not by very much and
highs should still be getting into the 50s for most locations.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1234 PM CDT Tue Apr 17 2018

Largely VFR, but a storm system will move across Iowa and a cloud
shield will potentially bring MVFR clouds northward to our
southern TAF sites after 06Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  40  26  38  25 /   0  10  20  10
INL  45  25  45  24 /   0   0   0   0
BRD  44  28  41  27 /   0  10  30  10
HYR  40  24  37  26 /  10   0  30  10
ASX  38  25  36  27 /  20  10  30  20

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 4 PM CDT this afternoon for LSZ141-
     142.

     Small Craft Advisory until 11 PM CDT Wednesday for LSZ140.

&&

$$

UPDATE...Wolfe
SHORT TERM...Huyck
LONG TERM...LE
AVIATION...Wolfe


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