Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 121519
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1019 AM CDT Sun Jul 12 2020

.SHORT TERM...(Today through Monday)
Issued at 442 AM CDT Sun Jul 12 2020

Today will be another lovely day for outdoor activities with a
weak ridge of high pressure over the area with light winds. A
field of diurnal cumulus should develop for the afternoon hours. A
few models develop some afternoon showers along the lake breeze
boundary along the North Shore, but the low level airmass is
relatively dry, and am not terribly convinced these showers will
develop and have left them out of the forecast for this afternoon.
Tonight will also be quiet with southerly flow increasing as the
high pressure ridge slides off to the east.

Monday and Monday night a cold front will advance toward the
area. Ahead of it, a surge of warm moist air will move in from the
south, pooling ahead of the cold front, setting up afternoon CAPE
values over western MN of over 1500j/kg and westerly bulk shear
values of 35-40 knots. A shortwave moving through the
southwesterly flow aloft across the Dakotas will intersect with
the cold front Monday afternoon over eastern North Dakota, and we
should see convective initiation during the late afternoon along
the MN/ND border region. Some of these storms will be strong to
severe, especially during the afternoon and evening hours. Later
on during the overnight hours the storms should weaken, but is
still a fairly big question mark if they weaken before or after
the storms move into the CWA. The Storm Prediction Center has
placed the western CWA into a Slight Risk. By the time the storms
move in, they should have formed into a linear mode, which should
bring damaging winds and large hail threats. I have slowed down
pops as they move into the forecast area as compared to previous
forecasts, and we will have to see what further adjustments are
needed in the coming forecast runs.

.LONG TERM...(Monday night through Saturday)
Issued at 442 AM CDT Sun Jul 12 2020

Tuesday the showers and thunderstorms continue east across
northwest Wisconsin. Instability is expected to decline, as well
as the severe weather threat, as the cold front moves into
Wisconsin. Once the front moves through, the Northland will stay
under the influence of the upper level trough on Wednesday as it
deepens and could bring another round of showers and
thunderstorms. Disagreement in the global model suite indicates
uncertainty in the coverage and placement of the showers.

Early Thursday, the trough should move east and by Thursday
afternoon, another trough should make its way to our area from
North Dakota, along with chances of showers and thunderstorms. The
trough should move east and out of our CWA by late Friday
morning.

In the evening on Friday, yet another trough should follow the
first. More showers and thunderstorms will be possible across the
Northland into Saturday early afternoon as it moves east. But
wait, we`re not done yet! Another upper level trough is expected
to follow, with another round of showers and thunderstorms Sunday
night into Monday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 620 AM CDT Sun Jul 12 2020

VFR conditions are expected to continue in the next 24 hours. Fog
is dissipating and should be clear in a couple hours. More fog is
possible tonight as well across the region.

&&

.MARINE...
Issued at 1019 AM CDT Sun Jul 12 2020

High pressure centered over northern Minnesota will keep
conditions quiet over western Lake Superior today through Monday.
Winds will be variable in direction this morning turning southerly
this afternoon at 3 to 8 knots. An area of low pressure will
develop in the western Dakotas Monday and will push northeastward
into Ontario by midday Tuesday. The low will be accompanied by a
cold front which will touch off thunderstorms in the Dakotas
Monday afternoon. The storms will move eastward over Lake Superior
Monday night and early Tuesday morning. Winds over the lake will
be from the northeast ahead of the front Monday at 5 to 15 knots.
The storms will bring a potential for large hail, gusty winds, and
torrential rainfall.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  78  57  80  62 /   0   0  10  90
INL  80  58  83  58 /  10   0  20  90
BRD  81  60  84  64 /   0   0  20  90
HYR  79  55  84  65 /   0   0   0  90
ASX  79  56  85  64 /   0   0   0  80

&&

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

$$

SHORT TERM...LE
LONG TERM...LE/Kossen
AVIATION...LE/Kossen
MARINE...Huyck


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