Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 152129 CCA

Area Forecast Discussion...CORRECTED
National Weather Service Duluth MN
429 PM CDT SAT OCT 15 2016

.SHORT TERM...(This evening through Sunday)
Issued at 405 PM CDT Sat Oct 15 2016

Concern for short term is timing of precip chances Sunday

Current surface analysis indicates cloudy skies across most of
the forecast area with sunny skies west of a Crane Lake to Lake
Winnie line. This clearing line will continue to move east this
evening giving the region clear to partly cloudy skies overnight.
With the clear skies, temperatures will drop into the 40s across
the area. Sunday will start mostly sunny but the clouds will be on
the increase as a frontal system approaches from the west. There
will be a possibility of a scattered shower or isolated
thunderstorm from Lake Winnie to International Falls Sunday
afternoon. High temperatures will be in the 60s once again with
50s along Lake Superior.

.LONG TERM...(Sunday night through Saturday)
Issued at 405 PM CDT Sat Oct 15 2016

The main challenges during the long term involve thunderstorm
chances and intensity Sunday night through late Monday night and
temperatures thereafter.

A compact shortwave trough will rotate into the Northland Sunday
night through mid-morning Monday. A warm front is forecast to lift
northward into central and portions of northern Minnesota by late
Sunday night. Southeast winds will veer southerly behind the
boundary with relatively warm and moist air pushing northward into
the MN-210/US-2 corridor. Temperatures in the upper 50s to low 60s
and dewpoints in the upper 40s to near 60 degrees are forecast to
follow the front into my southern CWA overnight. Cooler air
advecting over top the relatively warm and moist low-levels yields
forecast elevated CAPE of 500-1250 J/kg per the GFS and 1500-2000
J/k per the NAM. Effective bulk shear on the order of 35 to 45
knots, along with the afore mentioned instability, is supportive
of elevated supercells and large hail. Many questions remain,
however. Several of the high resolution and mesoscale models
feature a stout capping inversion above the warm frontal surface,
which may inhibit the development of vigorous thunderstorms. The
15.12Z NAM profiles do suggest a few hours of uncapped instability
for parcels residing in the 925 mb to 850 mb layer. This scenario
certainly bears watching and we agree with the SPC inclusion of a
Marginal Risk of severe thunderstorms Sunday night, focusing on
the hail potential.

The warm front is forecast to stall or drift slowly southward on
Monday, remaining near the Northland until a stronger push of cold
air arrives late Monday night and Tuesday. Another shortwave will
move into the region Monday afternoon, with a surface low quickly
moving east across the Dakotas along the stalled front. By Monday
evening, the ECMWF and NAM bring the compact and intense area of
low pressure to near eastern Lake Superior. The GFS is a bit
slower with the feature. Several additional periods of rain and
thunderstorms seem likely Monday through late Monday night,
although the best instability and convergence seems to be focused
south of the CWA at this time. With the position of the front and
storm motions parallel to the boundary, there is a potential for
locally heavy rainfall Monday afternoon and Monday night over
portions of east-central Minnesota and northwest Wisconsin.

A few showers may linger into Tuesday morning over northwest
Wisconsin, but otherwise Tuesday is looking much drier and quieter
across the area. Cyclonic flow aloft is expected to continue with
cutoff upper low, an artifact of Sunday night`s shortwave, slowly
drifting across the Canadian Prairies and into far northern
Ontario by Tuesday night. Cold air advection doesn`t appear as
strong as it did yesterday, and temperatures will only cool to
near or slightly below normal for the second half of the week.
Still, the cool down will be quite a change from the much above
normal values of the next few days. With the cyclonic flow aloft
and CAA continuing, a few showers are possible across far northern
Minnesota Tuesday afternoon and Tuesday night.

Models remain in fairly good agreement through Wednesday evening.
As the northern stream low pushes into northern Quebec, a brief
period of quasi-zonal flow will develop for Wednesday into
Wednesday evening. Quiet and relatively cool conditions will
continue into Wednesday evening. Confidence diminishes after
Wednesday as model solutions diverge through the end of the week.
The GFS and ECMWF are in better agreement today, but differences
remain. The ECMWF has a more progressive solution with the deep
longwave trough moving through the region Thursday through
Saturday, while the GFS deepens the trough into a cutoff low over
the western Great Lakes. With the differences in solutions, kept a
dry forecast with temperatures slowly moderating through the end
of the week.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1256 PM CDT Sat Oct 15 2016

Cold front stretched from southwest Minnesota into the Minnesota
Arrowhead at 18Z. The boundary will advance eastward across
northwest Wisconsin this afternoon and early this evening. MVFR
ceilings and scattered rain showers were found ahead of the front,
mainly affecting DLH and HYR. Much drier air was found behind the
boundary and ceilings quickly lift to VFR after frontal passage.
VFR conditions are expected to prevail for the remainder of the
forecast period, except at HYR where a period of MVFR fog is
possible overnight. Winds may remain higher overnight than
expected. Should winds stay up at HYR, fog potential would
diminish significantly. Winds will eventually veer northeasterly
and then easterly overnight and early Saturday. Upslope flow off
Lake Superior at DLH could result in low stratus development after
16.14Z. Not confident enough with this package to add ceiling, but
did include SCT. Overall confidence with this forecast is above


DLH  44  58  51  61 /   0  10  70  30
INL  40  60  49  62 /   0  20  60  10
BRD  43  64  58  64 /   0  10  60  20
HYR  44  67  58  68 /   0   0  70  30
ASX  46  61  54  65 /   0   0  70  30


.DLH Watches/Warnings/Advisories...


SHORT TERM...Stewart
AVIATION...Huyck is the U.S. government's official web portal to all federal, state and local government web resources and services.