Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 270441
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1141 PM CDT Wed Apr 26 2017

.UPDATE...
Issued at 655 PM CDT Wed Apr 26 2017

The precipitation has ended over the Arrowhead and have dropped
the advisory. The anticipated light freezing rain event due to
affect Ashland, Iron and Price counties has slowed per latest
short term models and have adjusted the start time of the advisory
to better match the onset of the freezing rain. Elsewhere, as an
upper low meanders around the Red River Valley of the North, some
light snow is falling from International Falls to near Staples.
This is because of a vorticity max rotating around the upper low
over this area. Near the head of Lake Superior, a northerly flow
over the lake was resulting in some light mixed precipitation
types from Douglas to Bayfield, and Pine to Burnett and Washburn
counties. Made some adjustments based on these trends.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 333 pm CDT Wed Apr 26 2017

A low over northeast Wisconsin will lift into eastern Lake Superior
this evening. Meanwhile, an upper low over southeast North Dakota
will slowly shift east into northwest Minnesota through this
evening. The low, which brought a surge of moisture aloft northward
into the Northland last night and this morning, combined with
unseasonably cold northerly low-level flow to produce widespread
freezing rain, sleet, and snow across much of the Northland. The
worst conditions of this wintry weather occurred early this morning,
and the precipitation will continue lifting north and diminishing
through this evening as drier air aloft works its way into the
Northland from the south. Only low chances of drizzle, freezing
drizzle, and very light snow are forecast for much of the Northland
by late this afternoon through this evening. The eastern Arrowhead,
which was under an Ice Storm Warning, will have a winter weather
advisory in effect for this evening for freezing drizzle and
light snow this evening. The winter weather advisories have been
cancelled for the rest of NE MN and a portion of NW WI except for
Ashland and Iron counties which has been extended to Price
County.

Cold air will continue to wrap into the Northland tonight and early
Thursday as that upper low wobbles around over northwest Minnesota.
Temperatures will drop well into the 20s. Another area of low
pressure will lift from Illinois this evening to eastern Lake
Superior by Thursday afternoon. It will bring another surge of
moisture northward to the region late tonight and Thursday, possibly
bringing precipitation as far west as some parts of northwest
Wisconsin (such Price/Iron/Ashland counties) and the tip of the
Arrowhead. The latest models have generally shifted that
precipitation farther east, so was able to decrease the
precipitation chances and amounts across the eastern forecast area.
This next round of precipitation could bring additional freezing
rain and snow, with potential light amounts of glazing from any
freezing rain. As mentioned above, the winter weather advisory has
been expanded to include Price county for tonight and Thursday
morning to Price County for the freezing rain and light snow
threat.

The precipitation near the eastern forecast area will move away from
the forecast area in the afternoon. Meanwhile, the upper low over
northwest Minnesota will lift to north central Minnesota, and cold
and drier air will work its way into the Northland amidst amids a
cold north-northwest breeze. There could be some very light snow
across northern Minnesota, but little if any accumulation. Highs
should reach the upper 20s and lower 30s in northern Minnesota,
while the middle and upper 30s in northwest Wisconsin to central
Minnesota.

.LONG TERM...(Thursday night through Wednesday)
Issued at 333 pm CDT Wed Apr 26 2017

A vertically stacked low will move northwards from Ontario on
Thursday evening into Hudson Bay by Friday evening. Precipitation
chances will gradually diminish from south to north through Friday,
as the 500 hPa cutoff rotates northward. Precipitation will
initially be all snow before surface temperatures warm into the
upper 30`s and 40`s throughout the Northland.

A low amplitude ridge will build into the Northland from the
Northern Plains on Saturday into Saturday evening. This will provide
a respite from precipitation with milder temperatures in comparison
to Thursday and Friday. Highs range from the 40`s adjacent to the
Lake Superior Shoreline, to the 50`s inland.

Precipitation chances return Sunday into Monday. At 500 hPa a potent
positively tilted trough will dig from the Intermountain West on
Saturday, and become neutrally/slightly negatively tilted as it
moves into the Central Plains and Mid Mississippi River Valley on
Sunday. The surface response will be lee cyclogenesis across the
Southern Plains on Sunday. The low will lift north northeastward
into Upper Midwest, which will spread precipitation in from south to
north on Sunday into Monday. The latest ECMWF shifts the lows track
farther west when compared to the previous ECMWF. This is more in
line with the previous and latest GFS. The only outlier in
deterministic guidance at this point is the GEM where the low moves
across eastern Wisconsin. If the GEM solution verifies it would
bring little to no precipitation to much of northeast Minnesota,
whereas the GFS/ECMWF would bring precipitation to northeast
Minnesota. Precipitation chances from this system could linger into
Tuesday, however there are timing differences with the GFS moving
the system out faster in comparison to the ECMWF/GEM. While it is
still too early to determine specific precipitation types for this
system, a wintry mix of freezing rain, sleet, snow and rain are
possible if the thermal profiles from the latest guidance hold true.
Those with travel plans on Sunday and early next week should stay
tuned for future updates. High temperatures will fluctuate through
the extended period, while lows remain generally in the 20`s and
30`s throughout the Northland. Despite the fluctuating highs,
temperatures will remain below normal through the extended.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1141 PM CDT Wed Apr 26 2017

Expect MVFR ceilings through the forecast, with some isolated
pockets of IFR. Snow showers will be in the vicinity of BRD
through the first part of the forecast. Mixed precipitation will
be in the vicinity of HYR around 13Z. Confidence is low on
precipitation actually affecting these terminals, so VCSH used. As
the upper low departs late in the forecast, some additional
showers may be found in the vicinity of all terminals but BRD.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  23  34  26  44 /  20  20  20  10
INL  20  32  24  42 /  20  30  40  20
BRD  24  39  27  47 /  20  20  10  10
HYR  28  38  26  46 /  20  40  10  10
ASX  27  37  27  45 /  30  50  20  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory from 4 AM to noon CDT Thursday for
     WIZ003-004-009.

MN...None.
LS...Small Craft Advisory until 10 AM CDT Thursday for LSZ121-140>148.

&&

$$

UPDATE...GSF
SHORT TERM...Stewart
LONG TERM...WL
AVIATION...GSF


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