Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 270528
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1228 AM CDT WED JUL 27 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 348 PM CDT Tue Jul 26 2016

The weak cold front that has sagged into the forecast area so far
today has been generating some weak showers with a few rumbles of
thunder along it.  It currently extends from the South Dakota/North
Dakota border area east to Lake Superior.  The atmosphere is
actually quite unstable with 2000 J/KG CAPE along with decent shear
of deep layer shear of 35 kts, so convection should continue to
fester along the boundary this afternoon and tonight. The trigger is
pretty wimpy,  otherwise we would have more convection than we do.
This front will continue to sag south tonight, and should be south
of the forecast area by early Wednesday morning.  Models continue to
bring weak shortwaves along the front, generating areas of showers
and thunderstorms that move across the area.  Since the triggers are
so weak am not terribly confident in timing, and the models are
showing this with a variety of start times and locations for
convection.  Thus, have kept pops in the chance category for the
most part, with the exception of tomorrow afternoon where there
appears to be more agreement and have gone with higher pops across
our south.  Tonight the clearing skies behind the front and drier
air moving in from the north should allow temperatures to fall into
the 50s along the international border, but should stay in the 60s
closer to the boundary.  Wednesday the cloud cover and precipitation
chances should keep temperatures cooler than today, and have
temperatures mainly in the 70s.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 348 PM CDT Tue Jul 26 2016

Cooler late this week as high pressure builds in from the north.
Late in the weekend warmer air returns as the high pressure moves
off to the east and southerly winds prevail. A chance for rain late
Saturday night into Sunday as a warm front lifts east-northeast
across the upper Midwest. Warmer early next week with a chance for
thunderstorms in the warm sector, though as a ridge builds in the
better chance for storms will not be until a mid-level shortwave
trough ejects out of the Colorado Rockies into the northern Plains
late Monday.

On the synoptic scale the near-zonal flow aloft gradually becomes
northwesterly mid to late week as a ridge builds across the west
coast, struggling to maintain itself as a series of weak mid-level
shortwave troughs move in across southwest Canada. Across the
Midwest a longwave trough deepens through the work week, gradually
lifting northeastward towards New England over the weekend. A cool
Canadian High Pressure will build in over the upper Great Lakes late
this week leading to cooler temperatures and north to northeast
winds...leading to Thursday being the coolest day in nearly two
weeks with highs in the mid to upper 60s along the Lake Superior
shoreline and low to mid 70s inland. (While we`re currently
forecasting a high of 73 at the airport, the last time Duluth had a
high in the 60s was July 14 (66) and before that June 27 (65).) The
high pressure will also result in mainly sunny skies Thursday,
Friday, and Saturday.

Over the weekend the area of high pressure moves off to the east
resulting in southerly flow returning to the upper Midwest. The
warmest air aloft will remain farther west across the high plains
over the weekend, with this airmass gradually building eastward
early next week. A warm front will build north through the region
over the weekend, but there will be a lack of deep moisture to
produce widespread precipitation. The warm air will be building in
along a ridge axis, and until that ridge axis is across the
Northland (late Monday) storm coverage will likely be scattered at
best.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1228 AM CDT Wed Jul 27 2016

A stalled front will keep scattered showers and thunderstorms across
the forecast area through much of the TAF period. Due to the
uncertainty in coverage and timing have carried VCTS/vcsh with an
TEMPO at times at all terminals overnight...except KINL which is
located north of the favorable axis of instability to support
convection. Have a Transition to broadbrush VCSH Wednesday
afternoon as the boundary starts to push south and instability
decreases over the area.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  52  73  52  75 /  20  10  10   0
INL  52  76  52  79 /   0   0   0   0
BRD  57  76  56  77 /  20  10  10  10
HYR  54  75  52  77 /  60  20  10  10
ASX  56  72  53  77 /  30  10  10   0

&&

.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...Small Craft Advisory from 10 AM this morning to 10 PM CDT this
     evening for LSZ144>146.

     Small Craft Advisory from 10 AM this morning to 4 PM CDT this
     afternoon for LSZ143.

&&

$$

SHORT TERM...LE
LONG TERM...JJM
AVIATION...Graning/Melde


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