Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 180828
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
328 AM CDT Sun Jun 18 2017

.SHORT TERM...(Today through Monday)
Issued at 328 AM CDT Sun Jun 18 2017

A deepening semi-vertically-stacked area of low pressure over
northeast Wisconsin and western Upper Michigan will lifting and
exiting to the east this morning. Rain showers associated with the
passing upper trough/low will linger over northwest Wisconsin and
parts of the Arrowhead through mid morning. There may be a break
in precipitation late this morning, leaving just cool and breezy
northwest flow. Daytime heating in this flow pattern will trigger
broken/overcast cumulus cloud coverage by early this afternoon.
Scattered light rain showers and isolated weak storms are expected
for the afternoon through early evening. Temperatures will be
nearly 10 degrees below seasonal normals, with highs in the low to
middle 60s.

The showers will dissipate this evening. Despite the cool flow
continuing tonight, with very light wind speeds, the lingering
cloud cover will help prop up the temperatures. Lows will be in
the upper 40s and low 50s.

Monday will be another cool day with breezy northwest flow.
However, it will be drier, so some areas will see some sunshine.
Very light showers are possible, mostly in the Arrowhead and
northwest Wisconsin. There is a low chance of weak storms across
the far southern forecast area. Highs will be in the middle to
upper 60s.

.LONG TERM...(Monday night through Saturday)
Issued at 328 AM CDT Sun Jun 18 2017

The beginning of the extended periods on Monday night should see
the western Great Lakes region underneath northwest flow aloft on
the western periphery of the larger scale mid level trof over
eastern Canada. There could still be a few showers or
thunderstorms around with lingering instability, but overall
increasing large scale subsidence and increasing low level ridging
should generally limit/decrease areal coverage Tuesday into
Wednesday.

By mid week, the medium range guidance still suggests that mid
level flow across the northern tier of the U.S. and southern
Canada will flatten and become more zonal as the eastern North
American trof deamplifies. As low level ridging slowly migrates to
our east, southerly return flow should gradually allow the
northern periphery of the warmth and instability axis over the
central plains to move back northward. Boundary layer moisture
content will also be increasingly aided by evapotranspiration as
the corn crop across NE/IA/srn MN is now growing in earnest.
Several weak waves moving through the flow should locally enhance
warm/moist advection over the northern plains, resulting in at
least some risk for thunderstorms.

Model guidance for the Wed thru Sat time frame is perhaps less in
agreement than it was yesterday, so exact timing and coverage of
any convection this far our is very difficult. While both the
GFS/ECM still try to bring a more significant short wave and
eventually larger-scale cyclogenesis to the northern plains and
adjacent Canadian Prairie Provinces in the Thus-Sat time frame,
the agreement on timing and placement is not very good at all.
Thus, we have not deviated much from the consensus guidance at
this time, which carries at least some risk for thunderstorms each
day during the mid to late part of the week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1249 AM CDT Sun Jun 18 2017

An upper level trough will remain over the region into Sunday
night with several shortwaves rotating through it. Showers and
some embedded thunder will continue tonight and be most numerous
over the southeast half of Northland including much of northwest
Wisconsin. The showers will diminish for a time late tonight into
Sunday morning but more will then develop as colder air aloft
continues to move in along with shortwave energy. Mostly VFR
conditions were occurring late this evening but MVFR ceilings are
expected to develop overnight into Sunday morning then gradually
lift Sunday afternoon/evening. Northwest winds will increase on
Sunday and be gusty at times.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  66  49  67  49 /  50  20  20  20
INL  62  47  65  46 /  50  20  20  20
BRD  65  50  69  51 /  20  10  20  30
HYR  67  51  68  49 /  60  30  30  30
ASX  67  51  68  50 /  50  30  30  20

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&

$$

SHORT TERM...Grochocinski
LONG TERM...Miller
AVIATION...Melde



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