Area Forecast Discussion
Issued by NWS Duluth, MN

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105
FXUS63 KDLH 222048
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
348 PM CDT Wed Mar 22 2017

.SHORT TERM...(This evening through Thursday)
Issued at 348 PM CDT Wed Mar 22 2017

High pressure over the Great Lakes region will continue to shift
to the east, and an upper-level ridge will move into the Northland
from the west this evening. Southerly flow will bring an influx
of warmer and more humid air into the Northland through tonight,
bringing increasing cloud cover. A shortwave trough will lift
from the northern High Plains through the Northland by the wee
hours of the morning, and the lift from the wave will help deepen
up the atmospheric moisture, likely deep enough to produce some
light snow. The best chances for the snow will be across the
Arrowhead, where up to a half inch of snow is possible. Other
parts of the Northland could get a light dusting.

The southerly flow will continue Thursday, with the upper-level
ridge axis shifting east of the Northland and shortwaves lifting
into the Northland in its wake. The shortwaves, combined with the
deepening moisture, will likely result in widespread light rain by
later in the afternoon. Highs will primarily in the 30s, but low
40s are forecast for north central Minnesota.

.LONG TERM...(Thursday night through Wednesday)
Issued at 348 PM CDT Wed Mar 22 2017

Main challenge for the long term include precipitation types
Thursday night through Monday. Temperatures should be cold enough
for a wintry mix during the night with mainly rain during the day.

A quasi-stationary frontal boundary is forecast to extend from
the Central Plains northeastward into the Minnesota Arrowhead
Thursday evening. A combination of convergence and isentropic
upglide should provide enough forcing for ascent to yield
precipitation beginning late afternoon or during the evening
hours. Initially, temperatures should be warm enough for all rain,
but a mix of rain, freezing rain, and snow will develop by mid-
evening. Warm temperatures aloft over portions of the Minnesota
Arrowhead and northwest Wisconsin raise concerns regarding the
availability of ice crystals for snow. A deep elevated warm layer
will also contribute to melting any snow which is able to develop.
The potential for freezing rain is greatest over those areas,
with the highest ice accumulation over portions of Ashland, Iron,
and Price Counties. As with most freezing rain events, antecedent
surface temperatures will play a significant role in the
precipitation type. Temperatures on Thursday should be in the
middle to upper 30s and could result in all rain for much of the
event. Given the continued uncertainty, elected not to issue any
headline products on this shift. Ice accumulation of around one-
tenth of an inch is possible, especially over portions of Price
County, and later shifts will need to re-evaluate the need for
headlines.

The band of precipitation will gradually drift southeastward
through our forecast area by late Friday morning as the front sags
south. Precipitation should change back to rain as intensity
slows. The 12Z deterministic models all trended drier over the
Northland for Friday through early Saturday morning, but the
ensemble members warrant keeping POPs over northwest Wisconsin. An
area of low pressure, which is forecast to loiter over the
Central Plains Thursday night and Friday, will wobble
northeastward Saturday and Sunday bringing a wintry mix back into
the picture. By Monday, high pressure will begin to push into the
area and will bring the precipitation to an end. Dry and quiet
conditions are expected for Tuesday and Tuesday night before
another chance of showers pushes into the area.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 100 PM CDT Wed Mar 22 2017

VFR conditions will continue this afternoon before lowering to
MVFR/IFR this evening and Thursday morning. A warm front aloft was
positioned over the eastern Dakotas this afternoon and will move
eastward into BRD late this afternoon or early this evening, and
through the remainder of the terminals by 23.06Z. Expect MVFR
ceilings along and behind the boundary. A relatively solid line of
snow showers accompanied the front early this afternoon. Expect
the snow showers to push into the terminals along with the front.
Visibility may decline to IFR where the heaviest snow showers
occur, most likely INL and HIB. BRD may experience IFR visibility,
as well, but confidence is lower at that site. The snow showers
will move out late overnight/early Thursday morning, but the MVFR
ceilings will linger.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  26  37  30  43 /  30  50  80  20
INL  25  43  29  40 /  10  40  50   0
BRD  30  39  32  47 /  10  50  70  20
HYR  26  38  33  45 /  20  40  90  50
ASX  25  39  31  44 /  30  40  90  30

&&

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

$$

SHORT TERM...Grochocinski
LONG TERM...Huyck
AVIATION...Huyck



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