Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 170600
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
100 AM CDT Sat Jun 17 2017

.UPDATE...
Issued at 100 AM CDT Sat Jun 17 2017

Please see the 06Z Aviation Discussion below.

UPDATE Issued at 1053 PM CDT Fri Jun 16 2017

Showers and a few thunderstorms continued across portions of the
Northland, with the stronger showers/storms occurring over
northern Wisconsin. A low level boundary and low level FGEN continues
to focus additional development over northwest Wisconsin and we
have adjusted POPs through the evening to account for the latest
radar trends. Much of the guidance is in agreement that overall
the coverage of the showers/storms will diminish overnight then
increase through the day Saturday.

&&

.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 06Z TAFS through 06Z Saturday night)
Issued at 100 AM CDT Sat Jun 17 2017

A cutoff low will continue rotating across Ontario through the TAF
period. Overnight a weak shortwave will swing through the
Northland. This has provided enough lift to generate showers and a
few isolated thunderstorms. Overall, expect this activity to
diminish as the night progresses which has also been hinted at by
the last few HRRR runs. Kept in VCTS at HYR due to thunderstorms
forming along a boundary nearby

A trough will dig into the Northern Plains Saturday afternoon and
into western Minnesota Saturday evening. This combined with
daytime heating and a cold front sliding southward will result in
scattered showers and thunderstorms developing. Still uncertain
how widespread the thunderstorm activity will be, so have kept all
terminals VCSH. Think the best chance for MVFR ceilings/visibilities
would be associated with any showers/storms that move over a
terminal from the activity Saturday afternoon/evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  54  73  52  65 /  50  70  60  40
INL  51  68  50  60 /  40  60  40  40
BRD  55  76  53  65 /  60  70  60  20
HYR  56  78  55  66 /  60  70  70  50
ASX  55  76  52  66 /  60  70  70  60

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&

$$

UPDATE...WL
SHORT TERM...GSF
LONG TERM...LE
AVIATION...WL



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