Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 250521

Area Forecast Discussion
National Weather Service Duluth MN
1121 PM CST Fri Nov 24 2017

Issued at 948 PM CST Fri Nov 24 2017

As temperatures are beginning to rapidly fall, there is a concern
for black ice to develop, especially on bridge surfaces. While the
below-freezing air is just coming into far northern Minnesota at
this hour, the low dew points (already in the 20s north of the
Iron Range) mean that wet bulb temps are already below freezing,
and thus ice could form on elevated and untreated surfaces, with
MNDOT road sensors indicating most road surfaces are at or just a
degree or two above freezing. Decided to issue a special weather
statement for parts of northern Minnesota to highlight this
threat. Otherwise forecast remains on track with a few small bands
of sprinkles moving across northeast MN at the moment.


.SHORT TERM...(This evening through Saturday)
Issued at 347 PM CST Fri Nov 24 2017

Main challenges for this forecast package are the potential for
mixed precip tonight and cool temperatures tonight and Saturday.

A narrow band of light rain showers stretched from southern
Minnesota to western Lake Superior. The showers were occurring
along and behind a cold front moving through the region. At 3 PM
temperatures ranged from the upper 30s in northeast Minnesota to
the low 50s in southern portions of Sawyer and Price Counties. The
deepest clouds were associated with a corridor of low- and mid-
level frontogenesis behind the front. Partly cloudy skies were
found farther west over Cass, Crow Wing, and portions of Aitkin
and Itasca Counties. The cold air advection aloft was wringing out
additional moisture in the form of low stratus over far north-
central and northeast Minnesota. Expect the rain showers and
deeper clouds to continue advancing eastward out of the forecast
area by this evening. As the cold air advection increases across
the north tonight, clouds should expand farther south once again.
Continued the earlier trends of light rain changing to a mix of
rain, freezing drizzle, and snow over northern Minnesota. A few
lake effect snow showers are possible overnight across snow belt
areas of northern Wisconsin. Nudged temperatures cooler for
tonight based on the strong cold advection. Look for low temps in
the low teens in northeast Minnesota to the upper 20s in northwest

A ridge of high pressure will scoot across the Northland on
Saturday. Cold air advection will continue through the day and
have lowered temperatures a few degrees to account for the longer
duration of CAA. Highs will be in the upper teens over interior
Cook County and the middle 30s along our southern CWA border.

.LONG TERM...(Saturday night through Friday)
Issued at 347 PM CST Fri Nov 24 2017

Surface high pressure will build across the region early in the
period, as an upper level ridge builds in the west. The result
will be dry weather from Saturday night through Monday morning. By
Monday afternoon, we could see some light precipitation across
the border region, due to warm advection in the vicinity of a warm
front pushing across far northern Minnesota. The surface low will
move across the Manitoba Lakes region during that time. The
precipitation could even linger into Monday night, as a cold front
drops across the region, putting the Northland into a fairly
strong cold advection regime. Heights will build again on Tuesday,
with dry weather continuing into Wednesday. Another upper level
shortwave will move through Wednesday night and Thursday, although
precipitation amounts are expected to be light. Upper level
heights will build again on Thursday and Friday, with a minimal
chance of precipitation during that time. In short, look for a
long term period where temperatures are reasonably mild, and there
is little weather expected. Highs throughout the long term period
are expected to reach the 30s to lower 40s.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1121 PM CST Fri Nov 24 2017

MVFR to VFR ceilings will improve to VFR by daybreak today as
skies generally clear out. Gusty northwest winds will continue
through the early morning hours, diminishing to around 5 knots or
less by mid-day. Increasing high-level clouds Saturday evening,
but remaining VFR through the rest of the TAF period with winds
becoming less than 5 knots and variable in direction.


DLH  21  27  20  35 /  10   0   0   0
INL  13  22  17  30 /  20   0   0   0
BRD  25  32  24  37 /   0   0   0   0
HYR  27  31  19  38 /  10   0   0   0
ASX  26  31  23  38 /  20  20   0   0


LS...Small Craft Advisory until 10 AM CST Saturday for LSZ121-140>148.



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