Area Forecast Discussion
Issued by NWS Duluth, MN

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000
FXUS63 KDLH 172345
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
645 PM CDT Fri Mar 17 2017

.UPDATE...
Issued at 638 PM CDT Fri Mar 17 2017

Updated aviation section below for 00z TAF set.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 334 PM CDT Fri Mar 17 2017

An area of low pressure with a center in northwest Ontario will
continue to move through the Northland tonight along with a cold
front. Precipitation will move through the area tonight with
chances highest across far northern Minnesota and in the snowbelt
region of Iron County. Area radars showed echoes from western
Minnesota north into northwest Ontario and southern Manitoba.
Surface temperatures as of 20Z ranged from around 30 at KCKC to
the lower to middle thirties most other areas. Forecast soundings
do show a loss of ice in spots this afternoon but as colder air
and deeper moisture move in this evening that will change.
Precipitation types will vary from light rain/drizzle, to snow, to
a period of freezing drizzle. We expect the coverage of freezing
drizzle to be limited and do not plan on any headlines. Much of
the guidance agrees in decreasing precipitation coverage for most
areas by late evening. The exception will be in the snowbelt
region of Ashland and Iron Counties which will see some lake
enhancement as 850MB temperatures cool to around -6C. Snow
accumulation there may be around an inch in spots.

An upper level ridge will build over the Northern Plains on
Saturday with a surface ridge over the Northland. Light
precipitation will linger in the morning over the snowbelt region,
otherwise it will be a dry day under partly to mostly sunny skies.
Highs Saturday will range from the lower to middle thirties along
the International Border, to the upper thirties to around forty
from the Brainerd Lakes area east to Pine City, Hayward, and Park
Falls.

.LONG TERM...(Saturday night through Friday)
Issued at 334 PM CDT Fri Mar 17 2017

In the big picture, most of the extended period looks to be
relatively tranquil as far as impactful sensible weather goes with
no big storms in the offing. However, there will be several low-
amplitude systems traversing the region, along with a few fairly
major airmass changes.

At the beginning of the extended periods, brief surface ridging will
be in the process of moving off to the east fairly rapidly, and this
will allow rather robust southwest low level flow to overspread most
of the western Great Lakes region Sunday/Monday.  The source region
for this airmass transition will be the downslope region of the
central high plains, meaning that the airmass should warm very
rapidly, despite lingering snow cover. Monday will be slightly
cooler with flow becoming more west/northwest with time, but the
major change will come with the amplification of a northern stream
wave on Tuesday, that will drag a strong arctic cold front southward
across the region.

A strong arctic high will amplify Tuesday/Wednesday, and should
push another 48-60 hour period of rather chilly air across the
western Lakes region.  Some favored areas in northeast MN could once
again dip below zero during the middle part of the coming week, and
in addition, the airmass looks to be sufficiently cold to result in
the potential for some accumulating lake-effect snow showers over
the favored areas of northern Wisconsin.  The ECM is considerably
more northerly (favorable) with its low level wind field forecast
for this period than the GFS, so there are still a lot of details to
be determined at this point in the process. A warm up is then
advertised toward the end of the 7 day forecast window, which may be
accompanied by some light precip.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 638 PM CDT Fri Mar 17 2017

MVFR/IFR ceilings continue over the terminals this evening, with
snow showers that reduce conditions to IFR. These snow showers are
expected to continue through approximately 05z, though there may
be more showers lingering and may have to amend TAFs for this in a
few hours. Even after showers end MVFR/IFR ceilings are expected
to continue through approximately 18z, with a gradual return to
VFR afterwards. Northwest winds 10-15 kts with gusts to 20 kts
this evening to continue through 12z, gradually diminishing in the
15-21z time range.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  24  37  24  48 /  50   0   0  10
INL  18  34  24  49 /  60   0  10  10
BRD  23  42  28  56 /  20   0   0  10
HYR  26  40  23  51 /  50   0   0  10
ASX  28  39  22  52 /  40  10   0  10

&&

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

$$

UPDATE...LE
SHORT TERM...Melde
LONG TERM...Miller
AVIATION...LE



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