Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 181545 AAB

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1045 AM CDT Tue Apr 18 2017

Issued at 1044 AM CDT Tue Apr 18 2017

Adjusted temperatures a bit cooler across our north to reflect a
slower diurnal trend than expected. Also held onto a mix of rain
and snow from northern Cass and Itasca Counties into the
Arrowhead, gradually pulling northeast with time. Temperatures are
in the middle 30s at Walker and Grand Rapids, but precip rates
are supporting mostly snow at those locations. Extended the Winter
Weather Advisory for portions of the Arrowhead, mainly for Cook
County. Light snow and freezing rain seem favored until at least
noon today.


.SHORT TERM...(Today through Wednesday)
Issued at 347 AM CDT Tue Apr 18 2017

Chances of precipitation will ramp up throughout the morning
today across the Northland as a potent mid-level shortwave sweeps
through the region. As of 3 AM CDT this morning, light to moderate
rain was falling across the Brainerd Lakes region, and points
north-northwest towards Itasca county. This precipitation will
only increase in areal coverage and intensity as the stronger 850
mb low-level jet makes its way across the area. Thanks to the
strong 50 to 60+ LLJ, moisture transport will be enhanced. The
NAEFS mean Pwat climatological values through the morning exceed
the 90th percentile, indicating an abundant flow of moisture into
the region. Initially, there is concern for a wintry mix,
especially from the Twin Ports and Cloquet areas north over the
Iron Range and into the Minnesota Arrowhead and North Shore
regions. Freezing rain, sleet, and snow are all possible as the
low-level thermal profile appears to support this wintry mix. Sfc
temperatures along Lake Superior will warm above freezing by mid
morning, but will remain at or below freezing before then, keeping
the door open for this wintry mix. Once temperatures increase to
above freezing, precip types will become all rain. Total QPF
amounts through the day today could range from one-half of an inch
up to one inch, mainly from Hinckley, MN to Ashland, WI and
points northwest. Lighter QPF amounts are expected southeast of
this corridor. Moreover, due to some small amounts of elevated
instability, there is a small chance for a rumble of thunder this
morning through the afternoon, mainly from the Brainerd Lakes
region, eastward into northwest Wisconsin.

Due to the potential for the wintry mix this morning, we have
extended the previous winter weather advisory to include all of
the North Shore, and the southern St. Louis county/Carlton county
zone. Temperatures in these areas are either at or below freezing
due to the on-shore flow from Lake Superior, so some ice accretion
on the surface may be possible once the precipitation arrives
later this morning. High temperatures today look to range from the
lower to mid 40s north to the upper 50s to near 60 south.

Tonight looks to be dry and quiet once this current system moves
off to the north and east. Sfc high pressure will advance over
Manitoba and Ontario Canada, which will briefly take control here.
This high pressure system will bring a brief respite from
precipitation through Wednesday morning. However, another system
looks to move in from Wyoming/Colorado and translate across the
central Great Plains. By the end of the short-term forecast
period, an inverted trough associated with the system, along with
850-700 mb layer warm air advection will generate another shot of
precipitation, which should be all rain, in the afternoon. Mainly
the southern portions of our forecast area will be most likely to
see precipitation from this next system.

.LONG TERM...(Wednesday night through Monday)
Issued at 347 AM CDT Tue Apr 18 2017

The main feature in the extended period will be an area of low
pressure that is expected to track from western Iowa Wednesday
evening into southern Wisconsin Wednesday night then toward the
Lake Huron area by Thursday evening. This track, which is similar
among most of the models, is further north than 24 hours ago. The
northward shift in storm track will cause a better chance for
precipitation over at least the southern half of the Northland
with chances highest over northwest Wisconsin. Forcing will
increase Wednesday night as the surface low moves into southern
Wisconsin. Strong FGEN forcing will develop over or near our
southern CWA. There will be precipitation type concerns as low
level temperatures cool Wednesday night. We decreased temperatures
Thursday due to precipitation coverage and off lake winds. We
have a rain/snow mix with all snow at times Wednesday night with
the precipitation transitioning to mainly rain as boundary layer
temperatures warm Thursday. There is concern we still may be too
warm with highs Thursday which would lead to higher snowfall
amounts. At this time, we expect a half inch to 2 inches from the
Twin Ports area east through northern Wisconsin but some locally
higher amounts will be possible.

The precipitation will end Thursday night as the low continues to
move off. An area of high pressure will bring a period of dry
weather to much of the Northland late Thursday night into much of
Saturday. There are model differences that become amplified over
the weekend. The ECMWF is faster bringing a cold front through the
area Saturday and is also faster moving an area of low pressure
into the region Sunday night into Monday. These features will
bring a chance for mainly light precipitation, with mostly rain
during the day and a mix at night.

High temperatures Friday through Sunday will be at to as much as
10 degrees above normal. The warmest days will be Friday and
Saturday, with Sunday cooler as the front moves through.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 655 AM CDT Tue Apr 18 2017

An area of low pressure over the the southeast North Dakota and
northeast South Dakota border will move to western Lake Superior
this afternoon, then continue east overnight. A mix of rain,
freezing rain, and snow will be possible early this morning over
portions of northeast Minnesota and extreme northwest Wisconsin
but should transition to all rain as the morning progresses. IFR
or MVFR conditions will become widespread this morning and
continue into the evening before some improvement occurs later
tonight in spots. KINL/KBRD will be most likely to see VFR
conditions later tonight.

LLWS will occur at KDLH/KHYR as a strong LLJ impacts those areas
this morning but will end as the LLJ weakens and shifts east.


DLH  45  34  45  33 / 100   0  30  40
INL  43  30  53  32 /  80   0   0  10
BRD  52  36  52  35 / 100   0  40  50
HYR  57  36  51  36 / 100  10  60  70
ASX  54  35  45  34 / 100  10  30  60


MN...Winter Weather Advisory until noon CDT today for MNZ012-021.

LS...Small Craft Advisory until 4 PM CDT this afternoon for

     Small Craft Advisory until 10 PM CDT this evening for LSZ140>142.



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