Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 142101

Area Forecast Discussion
National Weather Service Duluth MN
401 PM CDT Fri Jul 14 2017

.SHORT TERM...(This evening through Saturday)
Issued at 401 PM CDT Fri Jul 14 2017

AT 330 PM, skies were sunny across the Northland. Temperatures
generally ranged from 75 to 80, although it was cooler in spots
near Lake Superior.

The main focus for tonight and Saturday will be the chance of
showers and thunderstorms, as a weak frontal boundary moves
eastward across the region. While moisture (pwat around 1.25
inches) and instability (MLCAPE around 800 J/kg) will be a bit
limited across the area overnight, we should see the potential for
some elevated convection along and ahead of the front overnight.
The models offer myriad solutions in terms of overall coverage and
QPF, but will continue to carry chance POP`s across northeast
Minnesota tonight, and in the Arrowhead and northwest Wisconsin on
Saturday. Contemplated dropping POP`s a bit, but given the
convection currently in northern North Dakota and south central
Canada, opted to maintain the chance POP`s.

Despite the potential for spotty showers and thunderstorms,
Saturday is shaping up to be a generally dry day across the
region, with temperatures ranging from the upper 70s to middle
80s, and a gusty northwest wind developing during the day.

.LONG TERM...(Saturday night through Friday)
Issued at 401 PM CDT Fri Jul 14 2017

The main forecast challenges during the long term are warm
temperatures and a few rounds of thunderstorms, some of which may
be strong Monday night and Tuesday.

A high amplitude mid-level ridge will be situated over the
Rockies, Northern Plains, and Canadian Prairies. A few isolated
showers or thunderstorms may linger into the evening hours over
interior portions of northwest Wisconsin. A shortwave trough will
continue to move out of the Northland with increasing clearing as
high pressure builds in. Temperatures will trend a little cooler
behind the front on Sunday with highs in the 70s to low 80s. The
surface ridge axis will pass east of the Northland Sunday night
and Monday with southerly return flow developing. Expect warmer
temperatures for the start of the work week with highs from the
low 70s northeast to the middle 80s southwest. The mid-level ridge
will flatten and shift eastward on Monday, as well, in response
to an approaching longwave trough over the Canadian Rockies.
Surface low pressure is forecast to develop in the northern
Canadian Prairies with a cool front extending southwestward. The
trough and associated surface features will move eastward pulling
the cool front into northern Minnesota Monday night. A moderate to
strongly unstable airmass is forecast over the western CWA Monday
afternoon ahead of the approaching front. The NAM and GFS both
feature MUCAPE of 2000-3500 J/kg over our west. Thunderstorms may
be ongoing over eastern North Dakota and southern Manitoba during
the afternoon, moving into the Northland and northwest Ontario
during the evening. There is sufficient deep layer shear over the
area to support storm organization and there is a potential for
strong to severe storms. Another round of storms is possible
Tuesday as the cool front pushes through northwest Wisconsin.
Temperatures will trend near normal for the remainder of the long
term in the wake of the cool front. The boundary will likely stall
over the Midwest as a shortwave trough pushes eastward across the
Rockies. Surface low pressure is expected to develop along the
front with thunderstorms likely developing over the Central Plains
and the Dakotas. The storms are expected to push eastward along
the front as the surface low scoots eastward during the day
Wednesday. There is a slight chance of a few thunderstorms leaking
northward into the Northland late Wednesday through Thursday


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1241 PM CDT Fri Jul 14 2017

VFR conditions are expected to continue through this TAF period.
Surface high pressure over east-central Minnesota early this
afternoon will move southeastward into Illinois by mid-morning
Saturday. A cool front is forecast to move into the Northland from
the northwest tonight and move through the remainder of the area
on Saturday morning. Ahead of the front, west to southwest low-
level wind speeds will increase leading to a potential for LLWS
before the front arrives. Winds will turn northwesterly behind the
boundary bringing an end to the wind shear potential. A few
showers, or possibly a thunderstorm, will accompany the front over
northern Minnesota and have continued the mention of VCSH at INL
and HIB. Precipitation chances farther south and east are much
lower, so left out any mentions at DLH, BRD, and HYR. Confidence
in this forecast package is above average.


DLH  57  83  55  71 /  40  20   0   0
INL  57  78  50  77 /  40  10   0   0
BRD  59  85  57  78 /  20  10   0   0
HYR  53  85  55  75 /  20  20  10   0
ASX  55  84  55  70 /  20  20  10   0




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