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Area forecast discussion
National Weather Service Duluth Minnesota
328 PM CDT Mon Oct 14 2019

Short term...(this evening through Tuesday night)
issued at 328 PM CDT Mon Oct 14 2019

Upper level and surface ridging covered the forecast area this
afternoon. Drier air over the southern half of the region has led
to some clearing. Clouds were hanging on over the north where
more moisture was available and an embedded upper level impulse
was moving through and helping to generate these clouds. Even with
the cloud cover, temps have warmed into the 40s, except along the
Borderland and into The Arrowhead where upper 30s were found at
2pm.

The ridging prevails through this evening. Late tonight, a closed
upper low arrives in the Red River valley of the north, while its
surface low drifts into southern Minnesota. A fairly potent
vorticity maxima will reach western Minnesota overnight. Showers
will develop/spread into the southern portion of the region before
09z/4am, then continue north to the international border. Colder
temps just off the surface will lead to some snow mixing in with
the rain north of Minnesota Highway 210. No snow accumulation tonight.

The closed upper low moves into Wisconsin Tuesday, while the surface
low reaches Green Bay by late afternoon. The aforementioned vort Max
intensifies as it moves just ahead of the closed low. Cold air
advection on the backside of the upper/surface lows will work
together with the vort Max to keep the precipitation going,
especially over the southern half of the area nearest the low track.
The mixed precip types will continue until noon, then switch to all
rain. In northwest wisconisn Tuesday afternoon, some colder air
coming off of Lake Superior, will lead to a rain/snow mix in the
high terrain areas through the rest of the afternoon. A light
accumulation of snow is possible from southern Bayfield east through
central and southern Iron counties, but less than one inch.

Tuesday night finds the closed low reaching lower Michigan, while
the surface low moves to the eastern Great Lakes region. Additional
impulses will work over the area as well. The showers will persist
through the evening, ending from west to east overnight as high
pressure approaches. The rain/snow mix will switch to all rain as
boundary layer temps remain above freezing and is supported by
latest short term models.

Long term...(wednesday through monday)
issued at 314 PM CDT Mon Oct 14 2019

High pressure will be the main weather feature from Wednesday
through early Friday morning across the upper Midwest. A period
of quiet weather is expected. Temperatures will trend warmer
Thursday and Friday, and remain warm through the weekend.

An upper-level ridge is forecast to build across the region on
Wednesday and will amplify further on Thursday. Northwest flow in
the low-levels will support a chance of lake effect rain or snow
showers in the northwest Wisconsin snowbelt areas Wednesday
morning. A weak shortwave trough and associated vorticity
advection will move across Minnesota and Wisconsin Wednesday
night and Thursday morning. With limited moisture, expect a
slight increase in cloud cover to mark its passage. Precipitation
is unlikely with the passing shortwave trough. Winds in the low-
levels will turn westerly Wednesday afternoon and southwesterly
for Thursday ushering in a surge of 850 mb warm air advection.
The strongest warm air advection is expected Thursday night into
Friday morning before the next shortwave trough moves through the
region Friday afternoon and evening. Have raised low temps
Thursday and Friday morning and high temps during the afternoon
hours both days. Temperatures will be near normal on Thursday
with readings in the middle 40s in The Arrowhead to the middle
50s in central and north-central Minnesota as well as much of
northwest Wisconsin. Friday will trend above normal with highs in
the low 50s to low 60s.

The shortwave trough of Friday and Saturday morning will bring a
weak cool front through the region. There is a chance of light
rain with the system. Conditions dry out again for Saturday
afternoon through Sunday evening in response to weak ridging
aloft. Temperatures will remain a few degrees above normal
through the weekend. A more organized storm system will take
shape in the Central Plains Sunday afternoon and evening and will
bring a chance of precipitation to the Northland by late Sunday
night. The system will continue to affect the region Monday and
Tuesday of next week.

&&

Aviation...(for the 18z tafs through 18z Tuesday afternoon)
issued at 1249 PM CDT Mon Oct 14 2019

Low clouds associated with retreating low pressure in Ontario will
linger through the afternoon at hib/inl, causing MVFR ceilings.
Elsewhere, expecting VFR conditions this afternoon into tonight
with scattered clouds. Winds will generally be light this
afternoon, but cannot rule out an occasional gust to 15 kt. Winds
will be light and variable overnight.

Later tonight, low pressure will develop over southern Minnesota
bringing rain and snow to all terminals by around 10z. Rain is
expected at hyr with a rain/snow mix brd. Precipitation will
likely be all snow at dlh/hib/inl for several hours during the
morning before mixing with rain. Expecting visibility reductions
to MVFR and possibly occasionally IFR for terminals impacted by
snow. Most model guidance suggests that ceilings will become MVFR
late tonight and then IFR during the early morning hours at most
terminals.

&&

Marine...
issued at 328 PM CDT Mon Oct 14 2019

A ridge of high pressure stretched from northern Illinois to
southern Manitoba this afternoon. The pressure gradient will
continue to relax tonight as the ridge axis slides farther east.
Winds will remain westerly over the lake during the evening
hours. The ridge will push eastward tonight while an area of low
pressure rapidly develops over the Central Plains. That area of
low pressure will strengthen as it moves toward northern
Wisconsin and Upper Michigan by late Tuesday afternoon. The
pressure gradient over Western Lake Superior will tighten in
response to the passing surface low. Winds will back
northeasterly early Tuesday morning and eventually back northerly
to northwesterly by Tuesday night. Wind speeds and gusts will
increase in response to the tighter pressure gradient. Sustained
winds of 10 to 25 knots are expected with gusts as high as 30
knots possible from late-morning through late evening Tuesday.
The waters along the South Shore will experience the strongest
winds and a Small Craft Advisory is now in effect. There is a
small risk of gale-force gusts, especially late morning through
the afternoon hours Tuesday. The surface low will push farther
east into southern Ontario by Wednesday morning. The pressure
gradient over Lake Superior will relax and wind speeds and gusts
will diminish.

&&

Preliminary point temps/pops...
dlh 36 41 36 44 / 60 100 10 0
inl 36 42 36 44 / 40 50 20 0
brd 36 42 37 45 / 60 80 10 0
hyr 37 41 36 46 / 80 100 40 0
asx 35 42 39 48 / 70 100 60 10

&&

Dlh watches/warnings/advisories...
WI...none.
Minnesota...none.
Ls...Small Craft Advisory from 10 am to 10 PM CDT Tuesday for lsz121-
144>147.

Small Craft Advisory from 10 am Tuesday to 4 am CDT Wednesday
for lsz148.

&&

$$

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