Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 170929
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
429 AM CDT Sun Sep 17 2017

.SHORT TERM...(Today through Monday)
Issued at 429 AM CDT Sun Sep 17 2017

A pair of surface low centers were near the forecast area at 07Z.
One in the southeast corner of Manitoba, the other over Lake
Superior. A trof connected the two and was located right along the
international border. A cold front extended through northwest
Wisconsin from the Lake Superior low. Clouds were lifting to the
North from southern Minnesota toward northwest Wisconsin. Meanwhile,
plenty of low clouds were found over the area with more developing
just to the West and were moving into the forecast area. Even with
this cloud cover, low level drier air was working its way across the
region as dewpoints were dropping from the 60s near the cold front,
to the 40s over the western edge. This was thanks to high pressure
that was building into the area with the center currently in western
South Dakota. This high will drift over southern Minnesota by late
afternoon. Will see a gradual clearing trend through the day. Max
temps will be quite a bit cooler today with 50s north, and 60s
south.

The high will waft over to north central Wisconsin late tonight.
This puts the forecast area into a return flow pattern overnight.
Moisture will be advecting into the region late tonight and clouds
will be on the increase as a result. Warm air advection will also be
occurring tonight and will help to keep minimum temps in the 40s.

Even through the high will be near eastern Lake Superior through the
day, an upper level short wave trof moves into the region in the
afternoon. The moisture profile is not very deep, until late
afternoon, but with cold air advection from the south moving into
the area, will see some showers develop by late morning over the
western and southern edges of the forecast area. The shower chance
increases over the southern portion of the forecast area in the
afternoon and northwest Wisconsin, while diminishing over the north.
Model differences in the potential for QPF and placement were
handled by using a blended approach. No thunder is expected due to
the lack of instability. Max temps will be around 60 over the
Arrowhead, with lower to middle 60s elsewhere.

.LONG TERM...(Monday night through Saturday)
Issued at 429 AM CDT Sun Sep 17 2017

Mid-level ridging expected to bring relatively quiet conditions
Monday night and Tuesday transitioning to a more active regime
Tuesday night through the end of the period.

A deep longwave trough is forecast over the Intermountain West
Monday evening with a mid-level ridge over the western Great
Lakes and the Canadian Prairies. As high pressure departs to the
east Monday night and Tuesday, the building ridge aloft should be
sufficient to keep a dry forecast for the Northland. South to
southeasterly winds are expected and wind speeds will increase
during the day as the pressure gradient tightens between the
departing ridge and developing low pressure over southern
Alberta. The southeasterly breezes will work to keep much of
northeast Minnesota a little cooler thanks to the influence of
Lake Superior. Elsewhere, temperatures will trend a little warmer
with highs from the low 60s in the Arrowhead to near 70 degrees
in central and north-central Minnesota, and much of northwest
Wisconsin.

A strong cold front will advance eastward into Minnesota Tuesday
night associated with a strong shortwave trough rotating through
the Northern Plains and into northwest Ontario. The combination
of falling heights and convergence along the front should be able
to set off numerous showers and thunderstorms. The best signal
for storms is over western Minnesota and will spread into the
Northland overnight and Wednesday morning. High pressure will
build quickly behind the front Wednesday afternoon and a
strengthening mid-level ridge over the eastern United States will
keep conditions relatively quiet until Thursday evening.
Southerly flow over the nation`s midsection will pump
progressively warmer air and additional moisture into the
Northland late in the week. Look for unseasonably warm
temperatures in the middle 70s to low 80s by Friday, 10 to nearly
20 degrees above normal. Another round of showers and
thunderstorms is expected Friday through the weekend as a quasi-
stationary front sets up across the region. Several shortwave
troughs will ride along the boundary and rich southerly flow in
the boundary layer and mid-levels will support successive rounds
of rain and thunderstorms. By Sunday most of the instability will
be located south and east of the CWA with showers expected.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1240 AM CDT Sun Sep 17 2017

A cold front will continue to move eastward across the Northland
overnight, eventually ushering in cooler and drier high pressure
as the night wears on. Low clouds, and a few thunderstorms will
continue to linger for a time overnight, but those conditions will
gradually improve from west to east as the night wears on. A mix
of MVFR and IFR CIG`s and VSBY`s should give way to VFR conditions
area-wide on Sunday, as the high pressure builds in. It should
become a bit gusty at times on Sunday, especially during the time
of peak daytime heating.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  58  46  61  49 /   0   0  20  10
INL  54  41  64  46 /   0   0  10  10
BRD  62  46  65  50 /   0   0  20  10
HYR  62  43  63  49 /   0   0  40  20
ASX  63  44  64  48 /   0   0  30  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 7 PM CDT this evening for LSZ121-
     143>148.

     Small Craft Advisory until 7 PM CDT this evening for LSZ140>142.

&&

$$

SHORT TERM...GSF
LONG TERM...Huyck
AVIATION...DAP



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