Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 300545
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1245 AM CDT TUE AUG 30 2016

.SHORT TERM...(This evening through Tuesday)
Issued at 342 PM CDT Mon Aug 29 2016

Surface cold front is making slow but steady progress eastward
this afternoon, currently located from near International Falls to
far northeast South Dakota. The airmass along and ahead of the
front continues to destabilize, with MLCAPE values from 2000-3500
j/kg across much of the Duluth CWA, although there is still a fair
amount of inhibition that will need to be overcome before new
TStorms can initiate and sustain.

The overall thinking has not changed much since late this
morning. Thunderstorms are expected to develop between 5 and 7 PM
along a general axis from the Brainerd Lakes region, northeastward
through the Duluth area and the MN Arrowhead. Deep layer wind
shear is quite weak across most of the primary instability axis,
so the severe threat will likely be tied quite strongly to the
strong instability in place with pulse-type storms. The
combination of weak flow, and rather slow moving storms should
result in some potential for heavy rainfall rates/amounts
underneath the most persistent storms, and there will be at least
some risk of damaging wind gusts with wet microbursts, some of
which could be accompanied by hail with the largest/strongest
updrafts.

The front should continue to act as the primary forcing mechanism
through the evening, with the main axis of TStorms shifting
eastward into NW Wisconsin by late evening, and then exiting the
area out of Price County sometime after midnight.

Areas of fog will be possible overnight and Tuesday morning with a
decoupled and moist boundary layer, but should quickly mix out
during the morning as diurnal mixing commences. Otherwise, Tuesday
should be a fairly typical post frontal day with scattered cumulus
clouds and temps primarily in the mid 70s.

.LONG TERM...(Tuesday night through Monday)
Issued at 342 PM CDT Mon Aug 29 2016

An upper level ridge will extend from the western portion of the
Northern Plains well north into Alberta and Saskatchewan. This ridge
will slowly move east over the central plains into Manitoba and
northwest Ontario on Friday. A ridge of high pressure will be over
or just east of the Northland through this period and this
combination will provide dry conditions and seasonable temperatures.

A deep upper trough will move onto the Pacific Northwest Coast
Friday and a surface low pressure system will move into the Northern
Plains into Friday night and continue east into next weekend. There
are differences in how the GFS and ECMWF handle this low, but there
are also similarities considering how far out we are in time. There
will be a chance of showers/storms that occur with this low over the
weekend into Monday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1245 AM CDT Tue Aug 30 2016

High pressure will nudge its way into the area from Manitoba
behind an exiting cold front. This will bring clear skies tonight
with winds becoming light. Due to recent precipitation and current
observations, expecting radiation fog to develop at all terminals
except for KDLH. Think winds will remain too high at KDLH for fog
to form. Will see fog to bring visibilities down to the MVFR
range, with IFR possible at KHYR/KBRD.

After fog dissipates around 11Z-13Z expect VFR conditions to
prevail with winds less than 10 kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  51  74  52  69 /   0   0   0   0
INL  48  74  48  74 /   0   0   0   0
BRD  52  76  52  74 /   0   0   0   0
HYR  49  75  49  72 /   0   0   0   0
ASX  52  73  52  69 /   0   0  10  10

&&

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

$$

AVIATION...WL



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