Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 111447

Area Forecast Discussion
National Weather Service Duluth MN
947 AM CDT Sun Mar 11 2018

Issued at 947 AM CDT Sun Mar 11 2018

Positively tilted upper level trof with associated vorticity was
exiting northeast Minnesota and entering northwest Wisconsin late
this morning. A few snow showers were still dotting the landscape.
However, a transition to flurries was occurring behind the trof.
Expect this activity to diminish through the afternoon as the trof
departs. Did leave some small pops over the Arrowhead and the
eastern portion of the Wisconsin area for any leftover snow
showers/flurries/drizzle. Expecting temps to warm toward max
values this afternoon.


.SHORT TERM...(Today through Monday)
Issued at 435 AM CDT Sun Mar 11 2018

An inverted trough of low pressure will move through the
Northland today. Light snow and snow showers were observed over
much of the forecast area this morning. One of the heavier
bands deposited one- tenth of an inch of new snow at our office in
the past hour. Snow amounts of a couple tenths up to a half inch
is likely through this morning. A ribbon of vorticity stretched
from northwest Ontario to the southwest into central Nebraska
early this morning. A subtle shortwave trough was just ahead of
the vorticity and has enhanced upward vertical motion over
northern Minnesota. The shortwave trough and vorticity will slide
southeastward during the day, taking the surface trough along with
it. We expect light snow and snow showers to continue this
morning, gradually tapering off by late afternoon over southern

A more potent trough will dive southward from northern Canada and
nose into northeast Minnesota late this afternoon. Low-level
moisture seems sufficient for snow showers or flurries this
afternoon in northeast Minnesota, possibly mixing with or changing
to rain showers as temperatures warm. As winds aloft turn
northwesterly behind the morning disturbance, the potential for
lake effect snow or rain showers over western Lake Superior will
increase, continuing through Monday. Another surge of mid-level
moisture will move into northwest Ontario and northeast Minnesota
Monday afternoon as a third shortwave trough moves through. Snow
shower chances in northeast Minnesota and northwest Wisconsin will
increase during the afternoon and we have raised POPs as a

Temperatures remain near to above normal with highs today in the
middle to upper 30s and lows tonight in the teens to low 20s.
Highs for Monday dip a few degrees cooler with readings in the low
to middle 30s.

.LONG TERM...(Monday night through Saturday)
Issued at 435 AM CDT Sun Mar 11 2018

Monday night we will continue to get cyclonic flow and
instability driven showers on the west side of the shortwave over
eastern Ontario. The flow will also produce lake effect snow
showers along the south shore of Lake Superior into Tuesday
morning. The extra cloud cover should keep temperatures on the
mild side, despite the relatively cold air aloft.

A ridge of high pressure builds into the area for Tuesday as
ridging also builds aloft. The Lake Effect snow finally cuts off
by Tuesday night and Wednesday as dry air and a gradual change in
trajectory shifts it away from the area. Have increased the
diurnal range in temperatures, by both lowering min temps and
raising highs through Thursday as the night time clearing should
allow better radiational cooling and daytime sunshine and the
trees should boost afternoon temperatures.

Late this week we will be back into what has been a difficult to
forecast pattern this winter, with ridging over the central CONUS,
and cut off lows over the coasts. The pattern is somewhat blocky,
in which shortwaves ejecting out of the western low can have a
significant impact on the local weather, but have poor
predictability at this time range. For now, it appears there may
be one of these shortwaves as early as Friday, but only the GFS
shows it affecting the CWA, with both ECMWF and Canadian models
leaving us dry. Have left some slight to low end chance pops in
the forecast, but would not be too surprised to see these diminish
in upcoming forecasts. As we get into the weekend, there is
enough agreement that we might also be dry on that day, but by
Sunday and next Monday the upper low moves out of the Rockies and
should bring something to the region, but it may track too far
south to affect us with much in the way of precipitation.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 648 AM CDT Sun Mar 11 2018

A trough of low pressure will move across the Northland today
keeping stratus and snow showers in the picture. Ceilings should
remain VFR to MVFR today, even though model guidance has been
suggesting IFR in our west and north. Snow showers will gradually
taper off to flurries late this morning, with a few flurries
possible into the afternoon. Another upper trough will move into
northeast Minnesota late tonight and may bring another round of
snow showers and MVFR ceilings to northern Minnesota around 12Z.
2kft winds will strengthen overnight, especially near INL/HIB/BRD.
With this forecast LLWS is not a concern, but could be added with
later updates if forecast winds aloft increase.


DLH  37  17  34  14 /  80  10  10  10
INL  37  16  34   9 /  10  10  20   0
BRD  37  15  36  12 /  40   0   0   0
HYR  38  17  36  15 /  50  10  10  10
ASX  38  22  36  17 /  80  20  30  50




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