Area Forecast Discussion
Issued by NWS Duluth, MN

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793
FXUS63 KDLH 291816
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
116 PM CDT Sat Apr 29 2017

.UPDATE...
Issued at 1142 AM CDT Sat Apr 29 2017

Minor update to address a faster warming trend this morning.
Raised max temps slightly over north-central and central Minnesota
along with portions of northwest Wisconsin. Have also lowered
minimum relative humidity values based on trends this morning.
Some sites in far northern Minnesota have already dipped below 20%
RH.

&&

.SHORT TERM...(Today through Sunday)
Issued at 341 AM CDT Sat Apr 29 2017

An area of high pressure over the Northland and surrounding
region will continue to promote clear skies and negligible wind
speeds this morning, setting the stage for a warmer and drier day.
The high pressure will gradually shift north and east today as a
potent area of low pressure develops in the Southern Plains, and
breezy north-northeast flow will develop downwind of Lake Superior
across northwest Wisconsin and nearby areas of northeast
Minnesota. The warmest conditions will be from central to north-
central Minnesota, away from that cooler flow from Lake Superior,
plus there will be a little bit more afternoon cirrus over the
eastern forecast area compared to the west. Highs should range
from the upper 40s and low 50s in the Arrowhead, near Lake
Superior, and in northwest Wisconsin, to the middle 50s in central
and north-central Minnesota.

A potent, well-stacked area of low pressure will develop in the
Southern/Central Plains tonight into Sunday as it lifts towards
the Upper Midwest. The Northland`s influence from the Canadian
high pressure will gradually retreat as the low pressure
approaches the region. The Northland will see increasing cloud
cover aloft tonight into Sunday, and increasing chances of rain
from the south Sunday when initial shortwaves lift into north into
the Northland. Leaned on the drier models since it should take
some time for the elevated rain saturate the relatively dry low-
levels and reach the ground. Virga is more likely at first. It
should be warm enough, during this onset stage of this approaching
storm system, for precipitation during the day Sunday to fall
primarily as rain. Strong northeast flow will develop across
western Lake Superior Sunday in response to the approaching low
pressure, and that will translate to gusty flow downwind of the
Lake in northwest Wisconsin and east-central Minnesota, including
the Duluth area. Tonight`s lows should range from the upper 20s
and low 30s, and Sunday high`s should range from the lower 40s
near and downwind of Lake Superior, to the upper 40s to middle 50s
in central to north-central Minnesota.

.LONG TERM...(Sunday night through Friday)
Issued at 341 AM CDT Sat Apr 29 2017

Model discrepancies are in play Sunday night. The GFS/GEM/ECMWF
are fairly similar with the location of the closed upper low and
overall coverage of QPF. The NAM is drier, as it does not take QPF
to the Canadian border by 12Z Monday, while the other models do.
The ECMWF has the upper low vertically stacked with the surface
low, while the other models have the surface low displaced and in
different locations. The models continue with their differences,
now including the speed at which this system moves northeastward
on Monday. Used a blended approach for pops. Removed the mention
of freezing rain as forecast soundings from the various models do
not support a mention of freezing rain. This is also supported by
SREF and GEFS plumes. There will be a period of accumulating snow
possible late Sunday night and Monday morning, with a general 1 to
3 inches possible over northeast Minnesota, lesser amounts into
northwest Wisconsin. Some spots could see up to 4 inches in the
Brainerd Lakes region. This system slowly moves to the east Monday
night. The models become a bit more in sync taking the vertically
stacked low into eastern Lake Superior by 12Z Tuesday. Highest
pops will be over the eastern half of the forecast area due to
their proximity to the low as it departs. A rain snow mix is
expected in the evening before becoming all snow late. Light
accumulations are possible around the periphery of Lake Superior
where the coldest air will be found. The departing system will
send one more short wave trof over the region Tuesday. Since the
bulk of the moisture has moved off with the departing system, will
see some light snow in the early morning before mixing with, then
changing to all rain as the day goes on. Minimal accumulation.
Used a blend of pops to account for any differences. The ECMWF is
dry Tuesday night with high pressure nearby. The GFS and GEM are
quick to bring in the next round of precipitation. Used a
consensus which resulted in a dry evening, then bringing some pops
into the picture overnight, mainly over the western edge of the
area and along the Canadian border. The ECMWF remains dry on
Wednesday, while the GFS/GEM continue to spread pops across the
area. A blend was used for pops. This discrepancy persists
Wednesday night and Thursday. Stuck with the blend for pops. A dry
period Thursday night and Friday morning before a cold front
approaches in the afternoon for another chance at rain.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 112 PM CDT Sat Apr 29 2017

High pressure will gradually lose its grip on the Northland
overnight and into Sunday, although VFR conditions are expected to
continue throughout the period. Some mid and high clouds will move
in late tonight and Sunday morning, especially in the south.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  49  31  43  32 /   0   0  40  80
INL  56  28  55  33 /   0   0  10  30
BRD  58  33  49  34 /   0   0  50  80
HYR  52  32  45  35 /   0  10  60  90
ASX  47  30  42  34 /   0   0  50  80

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory from 4 AM Sunday to 4 PM CDT Monday for
     LSZ121-140>148.

&&

$$

UPDATE...Huyck
SHORT TERM...Grochocinski
LONG TERM...GSF
AVIATION...DAP



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