Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 171734
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1234 PM CDT WED AUG 17 2016

.SHORT TERM...(Today through Thursday)
Issued at 333 AM CDT Wed Aug 17 2016

Warmer with an increasing chance for storms Thursday afternoon with
a warm front moving in from the south and a cold front approaching
from the northwest. Feeling a bit more humid with mid 60s dew points
advecting in from the south ahead of the cold front.

On the synoptic scale a low-mid level ridge will build in across the
upper Midwest today with an associated surface high pressure
building across the mid-Mississippi valley this morning. While the
surface high is quick to weaken this afternoon, mid-level heights
remain steady as the ridge approaching from the west flattens out.
At lower levels warm air advection will ramp up through today and
tomorrow with winds out of the southwest at 850mb advecting in
around +20C air - not extreme but certainly on the warmer side of
normal for mid-August. A mature low will be gradually traversing
east across northern Manitoba Thursday with a cold front extending
down to a weak low developing across the central/northern highs
plains Thursday, with the cold front moving in from the west late
Thursday. Ahead of this a weak warm front will be moving in from the
south across southern/central Minnesota, but it`s unclear at this
point just how far north it will reach Thursday afternoon/evening.
At 18z THursday the GFS and NAM have the warm front along a Walker
to Lake Mille Lacs line, while the Canadian and ECMWF keep it
further south. A more southern solution will result in the worst of
the storms being focused farther south where the better instability
would be located, but if the warm front rises into east-central MN
or further north it would result in at least some strong to severe
thunderstorms.

Taking a step back, today looks mostly sunny across north-central
Minnesota with at least partly cloudy skies across the MN Arrowhead,
I-35 corridor, and east across northwest Wisconsin due to some
diurnal heating-induced cu developing in the late morning to early
afternoon, possibly resulting in some brief light rain showers.
Highs in the upper 70s to low 80s, with highs probably a few degrees
warmer in downtown Duluth compared to the airport up the hill due to
the weak west winds.

Fog likely developing again tonight as skies clear out, especially
in areas where showers develop today. Lows in the mid 50s to low
60s.

A few degrees warmer Thursday with highs in the low to mid 80s.
Sunny in the morning giving way to increasing clouds in the
afternoon across northeast Minnesota. Scattered showers and storms
increasingly likely over north-central Minnesota in the late
afternoon, approaching the Arrowhead, Twin Ports, and WI border by
the early evening. Some storms could be strong to severe with 30-40
knots of deep layer shear combined with 500-1500 j/kg MLCAPE
resulting in gusty winds and heavy rain rates, especially from the
Leech Lake/Brainerd Lakes region east to the I-35 corridor south of
the Twin Ports.

.LONG TERM...(Thursday night through Tuesday)
Issued at 333 AM CDT Wed Aug 17 2016

The extended period will begin wet and stormy.

Showers and storms will likely be ongoing or developing Thursday
evening with a low situated across Central Plain into MN, a cold
front in northwestern MN and a warm front from across central MN and
northern WI. A surge of warm air will be arriving Thursday afternoon
aided by a 35 kt low level jet. The strong nose of warm air will be
directed straight into north central Minnesota by evening, and
gradually shifts east through the night as the cold front moves into
Wisconsin late or toward morning.  Strong low level shear with SFC
to 3 KM at 41 kts and MUCAPES well over 3k J/KG can expect some very
strong to severe storms, especially south of U. S. Highway 2 in MN
and into adjoining northwest Wisconsin.  As per SPC that area and
points south are in the slight risk category for severe
thunderstorms. The front will make into northwestern WI but then
will stall out and remain nearly stationary until the upper level
trof comes through on Sunday. The position of the low and front will
keep the area from the MN Arrowhead through the Brainerd Lakes area
and all of northwestern WI in the rain area. The northwest area of
the DLH forecast area should be far enough away from the front to
remain.

A ridge of high pressure will bring drying weather Sunday and most
of Monday, but another upper level trough could bring a few showers
to far northern MN Monday afternoon.

Temperatures will be much cooler behind. The push of warm air will
bring 8h temperatures well into the teens and low 20s C Thursday
evening, then fall into the single digits Saturday that will last
into early next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1234 PM CDT Wed Aug 17 2016

VFR conditions expected through much of the upcoming TAF cycle.
High pressure will build over the Northland today and build eastwards
into the central Great Lakes on Thursday. Due to day time heating
and some instability, cumulus has developed across the region with
ceilings around 4-5 kft. Based on the latest NSSL WRF/HRRR and
current obs a few showers/storms will develop. Held off in
including this activity at KDLH/KHIB/KHYR as the probability is
low.

Overnight, patchy radiation fog is expected to develop due to
clear skies, light winds and recent precipitation. Think the best
chance of any fog is at KHIB/KHYR/KBRD between 06Z-13Z with
visibilities ranging from MVFR to LIFR. After 13Z expect VFR
conditions to return until the end of the TAF period. Will see
showers and storms move in from the northwest due to the incoming
cold front after 18Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  80  60  83  63 /  10  10  40  60
INL  82  58  82  59 /   0  10  70  30
BRD  81  61  84  63 /   0   0  70  70
HYR  80  58  83  64 /  20  10  40  60
ASX  82  61  84  65 /  10  10  30  70

&&

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

$$

SHORT TERM...JJM
LONG TERM...CLC
AVIATION...WL



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