Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 262050

Area Forecast Discussion
National Weather Service Duluth MN
350 PM CDT TUE JUL 26 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


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1235 PM CDT Tue Jul 26 2016

VFR conditions expected to continue to prevail at all TAF sites.
While coverage of showers waned late this morning...additional
showers and storms are expected to develop late afternoon and
overnight tonight at DLH...BRD...and HYR. Coverage of
thunderstorms is expected to be low thus went only with VCTS
during times when confidence is highest. Ceilings will remain VFR,
though cannot rule out a brief lowering to MVFR in heavy rain.
Visibility may also briefly lower to MVFR or even IFR during
periods of heavy rain, but because of the expected coverage of
showers and storms did not include any lowering visibilities in
the forecast for now. Light and variable winds through the period
as a stationary front remains along the Highway 2 corridor.


DLH  61  74  52  73 /  40  30  20  10
INL  55  78  52  76 /   0   0   0   0
BRD  62  77  57  76 /  40  60  20  10
HYR  62  78  54  75 /  40  60  60  20
ASX  62  76  56  72 /  30  40  30  10


.DLH Watches/Warnings/Advisories...
LS...Small Craft Advisory from 10 AM to 10 PM CDT Wednesday for

     Small Craft Advisory from 10 AM to 4 PM CDT Wednesday for LSZ143.



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