Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 201730

Area Forecast Discussion
National Weather Service Duluth MN
1230 PM CDT Tue Jun 20 2017

Issued at 1222 PM CDT Tue Jun 20 2017

Updated for the new 18z Aviation Discussion below.

UPDATE Issued at 645 AM CDT Tue Jun 20 2017

Updated for the new 12Z Aviation Discussion below.

UPDATE Issued at 536 AM CDT Tue Jun 20 2017

A small area of thunderstorms developed over Carlton county. Have
updated to add a mention early this morning. No other changes at
this moment.


.SHORT TERM...(Today through Wednesday)
Issued at 333 AM CDT Tue Jun 20 2017

An upper level trof was dropping southeastward through the forecast
area at 0730Z. At the surface, a weak trof was moving over the tip
of the Arrowhead. These features, combined with a strong vorticity
maxima, along the differential vorticity advection, were generating
some light rain showers over the Arrowhead. Meanwhile, some showers
were also clipping the southwest quad of the forecast area which
were also in response to the aforementioned vort max, and a coupled
jet structure. The showers will persist for a few hours this
morning, before moving out of the area by late morning. Very little
instability is associated with these showers, as evidenced by the
100 J/kg of MUCAPE over the southwest, have no mention of thunder.
Forecasted MUCAPE from the NAM and ECMWF also carry less then 100
J/kg through the morning which supports leaving out the thunder
mention. A second batch of showers is possible over the Arrowhead
this afternoon. This is in response to another shot of vorticity
that is progged to move nearby. Elsewhere today, high pressure will
be building in from the northwest. After some clouds through the
morning, some clearing is expected in the afternoon. Max temps will
be running a bit below normal today.

The aforementioned high pressure will drift southeast through tonight
and be in southern Wisconsin by morning. Will have a clear to mostly
clear sky to start, but will see clouds on the increase late tonight
as warm air advection begins and moisture arrives from the southwest.

On Wednesday, a fairly vigorous mid level trof will move into
western Minnesota by afternoon. Strong warm air advection ahead of
the trof, along with isentropic lift, will generate some showers.
The first batch will be over the western edge of the region by mid
morning. The chances of rain increase through the afternoon with the
Borderland see the greatest potential for rain. Thermodynamic
profiles suggest thunder being limited from the Brainerd Lakes to
near Hibbing, then north to the international border, in the late
afternoon. MUCAPE values will be less than 500 J/kg, thus only a
slight chance of thunder is mentioned. No rain is expected over
north central Wisconsin.

.LONG TERM...(Wednesday night through Monday)
Issued at 333 AM CDT Tue Jun 20 2017

The Northland will has near daily low chances of showers through the
forecast period. The best chance for rain and thunder is Wednesday
night. The latter half of the week will bring another cool down
which will bring cooler than normal weather through early next week.

A vertically-stacked area of low pressure will be over the
Saskatchewan and Manitoba border area by Wednesday evening. It will
be digging and moving east-southeast. It will be packing quite the
punch of wind aloft. A 130 knot jet streak will be too its southwest
near the Montana and Canada border area. Its surface cold front will
likely be over northwest Minnesota, the southern Red River Valley,
and into eastern South Dakota. Its warm front will likely extend
from northwest Minnesota through western Minnesota into Iowa.

The Northland will probably see showers and thunderstorms Wednesday
evening through the night with the lifting warm front and passing
cold front. The best chances for rain will likely be across the
western forecast area with the better large-scale forcing and more
consistent development along the cold front. The more widespread
rain will likely be across the southeast part of the forecast area,
closer to the warm front and more ample moisture when it`s lifting
through the that area in the evening. The overall threat of the
severe weather across the Northland is fairly limited because of the
lack of instability. Even though there will be plenty of deep layer
wind shear, the GFS, NAM, and SREF most unstable CAPE indicate only
about 500 to 1000 J/kg.

The cold front will quickly move through the Northland Wednesday
night, and the main low will be move through southern/central
Manitoba into far northwest Ontario Thursday morning. The Northland
can expect westerly flow to bring in much drier air into the region
Thursday. The sunny skies will provide decent afternoon mixing,
tapping into considerable flow aloft. The GFS has much stronger flow
than the NAM, but it seems to reasonable to at least anticipate the
NAM`s 10 to 15 mph winds with gusts of 15 to 30 mph by the late
afternoon. The stronger flow will be across northeast Minnesota. The
GFS suggests gusts over 30 mph. Highs will be in the low to middle

A secondary cold front will move through the Northland late Thursday
or Thursday night. This will set the stage for a cool weather
pattern Friday through early next week. Highs will be in the upper
60s to low 70s Friday, followed by the middle to upper 60s for the
weekend. Cool north to northwest flow, combined with the passage of
some weak shortwave troughs in the northwest flow pattern aloft,
will bring low chances of showers and thunderstorms. Most of the
those shower and storm opportunities will be during the peak heating
of the day, during the afternoon through the evening.

There is a significant difference between the GFS and European for
the weekend`s rainfall. The European has much greater and more
extensive rain than the GFS, in part due to a much more potent wave
passing through the region compared to the GFS. The Canadian is more
similar to the GFS.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1230 PM CDT Tue Jun 20 2017

VFR conditions expected through the TAF period. A diurnal cumulus
field has developed across the Northland, with cigs mainly
between 3.5 to 4.5 kft expected. There may also be a brief shower,
especially over the Minnesota Arrowhead region. Confidence is low
that these showers will affect the KHYR, KDLH, and KHYR TAF sites
through the afternoon, but cannot rule it out entirely.

An area of high pressure will then move into the region overnight,
supporting clear skies and light winds. There may also be some
patchy fog tonight, but much of the model guidance has the fog
becoming isolated and not expected to impact the Northland TAF


DLH  69  52  71  54 /  10   0  40  50
INL  67  48  71  52 /  10  10  60  60
BRD  72  51  75  56 /   0  10  40  60
HYR  70  49  75  58 /  70   0  30  50
ASX  69  50  74  56 /  30   0  30  50




LONG TERM...Grochocinski
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