Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 291723
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1223 PM CDT MON AUG 29 2016

.UPDATE...
Issued at 1023 AM CDT Mon Aug 29 2016

The morning MCS has largely dissipated as of 10 am, with only a
few meager updrafts remaining over west central MN, rooted well
above the low level cold pool. While we still have a rather
expansive area of debris clouds left over to deal with, skies are
clearing across the western sections of the CWA, which will allow
the diurnal heating/destabilization cycle to begin in earnest.
The primary surface cold front lies roughly from Lake of the Woods
to between Grand Forks and Fargo as of mid morning, with the
outflow boundary from morning convection having pushed well into
southern MN. Most short range guidance brings the cold front and
low level mass convergence maximum to an axis roughly from the
Brainerd Lakes area to Duluth and the North Shore by 4-5 PM, and
this should be accompanied by the redevelopment of more
thunderstorms along, or just southeast of this axis in the 4 to 8
pm time frame.

While instability should recover to fairly robust values of at
least 2000-3000 j/kg along and ahead of the front, the best deep
layer shear is well displaced to the northwest from the
instability axis. Thus, storms today may struggle with
organization and longevity, and any severe threat may be limited
to pulsy-type wet microbursts that could be accompanied by some
hail with the strongest of updraft cores. The one exception is
that low level shear will increase to 20-25 knots over NW WI after
00z, so some storms could become a bit better organized with a bit
better wind threat by mid evening in this area. Otherwise, the
slow moving front and relatively weak flow may confine the primary
threat to locally heavy rainfall until storms can clear northwest
WI after midnight. We have updated the forecast to reflect this
thinking, and we have also added a mention of fog tonight and
Tuesday morning over roughly the southeast half of the CWA where
winds will be weak, with a very moist boundary layer until NW
winds increase mid-late morning Tuesday.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 239 AM CDT Mon Aug 29 2016

Convective complex was moving through northeast Minnesota at 07Z.
Torrential rainfall and abundant lightning have been the main
hazards so far. The overall movement of this system was east-
southeast, with some discrete cells moving northeast as they develop
quickly ahead of this system. Rainfall amounts have been in the 1 to
2.5 inches range. Since the soils have been fairly dry, this rain
will be soaked up nicely. As this complex dissipates as it continues
on its trek through the forecast area, will see a brief break in the
action late this morning before the cold front arrives in the
western portion of the area by early afternoon.

Expect the next round of thunderstorms to fire up along and ahead of
the cold front in northeast Minnesota early in the afternoon. There
is some potential for the storms to approach severe levels, but will
be dampened a bit from this morning`s storm complex which will have
effectively overturned the atmosphere. With the lack of instability
and the potential for lingering cloud cover, that severe risk is
low. However, some heavy rain is possible once again as pwats are
above 1.50 inches.

The cold front should reach the border of Minnesota and Wisconsin by
00Z/7pm. The storms will move out of northeast Minnesota shortly
thereafter. The storms will continue through the night in northwest
Wisconsin. The amount of instability and the pwats drop as the front
reaches the edge of the Wisconsin zones by 12Z/7am Tuesday. As the
front departs early Tuesday morning, have lingered some low pops to
account for any leftovers until 15Z/10am. Behind the front, high
pressure will be building across the forecast area with a cooler and
drier airmass.

.LONG TERM...(Tuesday night through Sunday)
Issued at 239 AM CDT Mon Aug 29 2016

A quiet stretch of weather through the work week as a mid-level
ridge slowly builds across the Plains and Canadian Prairie...building
in towards the Great Lakes over the weekend. Behind the ridge a
longwave trough deepens across the west coast, leading to southwest
to southerly flow at mid to low levels for the weekend. At this
point it looks like the best moisture and instability would be
located to the west, only advecting into the Northland just ahead of
a cold front late in the weekend into early next week, but still
think showers and storms are possible ahead of the front through the
weekend.

Sunny skies through the work week until showers and storms are
possible Saturday and Sunday. Temperatures coolest Tuesday night
with lows in the 40s across parts of northeast Minnesota, then
generally seasonable through the rest of the week into the weekend
with highs in the low 70s and lows in the 50s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1223 PM CDT Mon Aug 29 2016

A cold front stretched from far northwest Ontario to near KINL
into South Dakota this afternoon. Scattered to broken clouds from
5KT to 25KFT were occurring this afternoon but we do expect some
cumulus development through the afternoon. As heating continues,
we do expect showers and thunderstorms to form along the front as
it moves through the Northland. Much of the guidance is in
agreement that it may take a couple more hours for initiation,
most likely after 21Z. Some strong to severe storms will be
possible, most likely at KBRD/KDLH/KHYR.

The wind will switch to the northwest behind the front tonight. If
winds are able to decouple overnight, some fog will form and we
have added to KHYR.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  81  57  75  51 /  60  40   0   0
INL  76  52  74  49 /  50  10   0   0
BRD  80  56  76  52 /  60  20   0   0
HYR  80  59  76  49 /  60  60  10   0
ASX  82  61  75  52 /  60  60  10   0

&&

.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&

$$

AVIATION...Melde



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