Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 181155
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
655 AM CDT Tue Apr 18 2017

.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.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  50  34  45  33 / 100  10  10  40
INL  44  30  53  32 /  80   0   0  10
BRD  55  36  52  35 /  90   0  30  50
HYR  59  36  51  36 /  80  10  30  70
ASX  56  35  45  34 /  80  10  20  60

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Winter Weather Advisory until 10 AM CDT this morning for
     MNZ010>012-019>021-037.

LS...Small Craft Advisory until 4 PM CDT this afternoon for
     LSZ143>145.

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

&&

$$

SHORT TERM...JTS
LONG TERM...Melde
AVIATION...Melde



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