Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 162353

Area Forecast Discussion
National Weather Service Duluth MN
653 PM CDT Fri Jun 16 2017

Issued at 653 PM CDT Fri Jun 16 2017

Please see the 00Z Aviation Discussion below.


.SHORT TERM...(This evening through Saturday)
Issued at 330 PM CDT Fri Jun 16 2017

A closed upper low over northwest Ontario will drift around this
same area this afternoon through Saturday. Embedded vorticity maxes
in the fast flow aloft will move over the forecast area through
Saturday. A longer wave trof will extend from the upper low
southwest into South Dakota by Saturday afternoon. This leads to
periodic episodes of showers and isolated to scattered
thunderstorms for late this afternoon through Saturday. First
group of showers and storms was forming along a surface boundary
from north of McGregor through southern Bayfield county to Hurley,
WI, which shows up nicely on KDLH radar. Additional showers were
beginning to pop along the Borderland. Virtually no CAPE along
the international border, so expect showers only. These pieces of
energy and their resultant shower and thunderstorm activity will
be difficult to time, although the HRRR has been doing a decent
job. Followed the HRRR and blend of other convective allowing
models for the rest of the afternoon and tonight. Min temps will
be in the 50s. The best opportunity for more widespread showers
and storms will be on Saturday. This is when a long wave trof will
cross into the Dakotas by the afternoon. A more vigorous shot of
vorticity moves into the base of the trof and will generate a more
generous area of showers and storms by afternoon across the
region. There will be some showers in the morning, especially
north of U.S. Highway 2 in northeast Minnesota. With more cloud
cover anticipated, max temps will be a bit cooler with upper 60s
along the Borderland, to the upper 70s over the southern tier of
the region.

.LONG TERM...(Saturday night through Friday)
Issued at 330 PM CDT Fri Jun 16 2017

Our upper low pressure system for tonight and Friday exits off
quickly to the east Friday night and Saturday, allowing a ridge of
high pressure to build into the area for Saturday night.  This
leaves us with some potential for below freezing temperatures for
both Friday night and Saturday night.  Have concerns for cloud cover
and wind both nights which could keep frost from forming or keep
temperatures a little too warm, but the potential is there and we
will need to reevaluate again tomorrow.  Saturday looks cool and
mostly cloudy.

Sunday our next weather system takes shape over southern
Saskatchewan and moves east across Canada, pulling some warmer
temperatures into the area for both Sunday and Monday and our
frost/freeze concerns diminish for both days.

Monday night through Tuesday night we have another upper level wave
moving across the area, which interacts with a decent baroclinic
zone lying over the forecast area.  This should bring another round
of precipitation to the area, with rain south and either a rain/snow
mix or all snow north.

Wednesday we have another ridge building into the area with enough
cold air to give us more potential for frost/freeze concerns.
Thursday and Thursday night the models are hinting at another wave
moving across the Midwest which should bring us some rainfall, but
there are some pretty significant differences in the models this far
out and have kept pops low for now.


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 653 PM CDT Fri Jun 16 2017

VFR through the TAF period, however there may be some periods
where MVFR ceilings/visibility develops if a shower/storm passes
through a terminal. Cyclonic flow will continue across the Upper
Midwest with a cutoff low rotating across Ontario. The combination
of the cyclonic flow and diurnal heating has brought scattered
showers and storms. Expect this activity to diminish once the
sun sets. Have held off in including any thunder mention at TAFs
this evening, as SPC mesoanalysis has MLCAPE off to the south, but
think the best chance of a thunderstorm this evening would be at
KHYR. Think there is a low chance of fog development at
HIB/INL/BRD, but suspect there will be too much cloud cover for
good radiational cooling.

A trough will dig into the Northern Plains on Saturday. This
combined with heating will result in scattered showers and storms
developing across the region per the latest guidance. Uncertain
on how widespread thunderstorm activity will be at this point, so
have left in as VCSH.


DLH  54  73  52  65 /  50  70  60  40
INL  51  68  50  60 /  40  60  40  40
BRD  55  76  53  65 /  50  70  60  20
HYR  56  78  55  66 /  30  70  70  50
ASX  55  76  52  66 /  50  70  70  60




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