Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 170553

Area Forecast Discussion
National Weather Service Duluth MN
1153 PM CST Thu Nov 16 2017

Issued at 1137 PM CST Thu Nov 16 2017

Not a whole lot of change from the days forecast package, trimmed
up PoPs and snowfall amounts to better coincide with radar trends.
We had the first frontogenetic snowfall band pass over the region
dropping about a 1/2" of snowfall over the twin ports. Still looks
like a mix of precip tomorrow morning as we warm up overnight, so
the morning commute could be a little tricky especially if it is
slow to warm.


.SHORT TERM...(This evening through Friday)
Issued at 200 PM CST Thu Nov 16 2017

After a mostly dry day today across much of the Northland, we once
again will be dealing with an incoming system that will bring a
wintry mix of precipitation, which should make for hazardous road
conditions, especially for the Friday morning commute.

A one-two punch of a warm front, followed by a push of cold air
advection on the backside of a sfc low that is progged to translate
across southern Saskatchewan and Manitoba Canada, will be the
culprits for this precipitation. Model soundings indicate that the
atmospheric profile will saturate this evening and overnight due to
seeder-feeder processes. The push of warmer air behind the warm
front will complicate the forecast as far as p-types are concerned.
RAP soundings indicate a warm layer of roughly 1 to 2 degrees
Celsius at around the 800 mb level, with perhaps even warmer
maximum temperatures possible. This would support a range of
p-types, including snow, rain/snow mix, drizzle, freezing
drizzle, and sleet. Overnight, temperatures should remain cold
enough through the atmospheric profile to support mainly snow,
with some isolated drizzle/freezing drizzle. The p-types become
more eclectic just in time for the Friday morning commute, with
drizzle, freezing drizzle, sleet, and snow all possible during
that time. Confidence in the exact timing and placement of each p-
type is rather low with this setup. The good news is that the
freezing precipitation will diminish by Friday afternoon as
temperatures look to warm up to the lower to middle 30s across the
area, with most locations seeing temperatures above freezing.
However, freezing precipitation will return Friday night and
Saturday morning. New snow should mainly fall over our
northeastern portions of the forecast area, especially over the
Minnesota Arrowhead, where up to 1" to 2" of new snow is possible
over Lake and Cook counties Friday. Ice accretions appear to be
very light, if any, with the best chances of icing over Price,
Ashland, and Iron counties in northwest Wisconsin. Due to the lack
of heavier accretions of ice, we will hold off on any headline
issuances at this time. Also, due to a tight sfc pressure gradient
moving in from the west, southerly winds will be gusty across the
area overnight, with gusts between 20 to 25 knots possible.

.LONG TERM...(Friday night through Thursday)
Issued at 200 PM CST Thu Nov 16 2017

The area of low pressure will move through northwest Wisconsin
Friday night, being pushed along by an upper level trof. The wintry
mix of ptypes persists, but expecting more of a drizzle/freezing
drizzle ptype, along with light snow. Dry over northeast Minnesota.
The precipitation diminishes in northwest Wisconsin as forcing
departs. Have some small pops Saturday morning as the wind aligns
for an opportunity for some light lake effect snow showers. However,
model differences in the amount of dry air advecting over Lake
Superior may offset the favorable wind. Ridging moves over the rest
of the forecast area Saturday. Confidence is low on lake effect snow
through Sunday morning with the dry air appearing to prevail. Warm
and dry air surges into the area Sunday night and Monday ahead of
the next system. Monday night finds this next system moving along
the international border region through Tuesday. A cold front is
progged to move through the region and bring the next round of snow
showers. As ridging returns for Tuesday night and Wednesday, lake
effect processes begin again with a northwest flow. Have adjusted
pops accordingly.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1137 PM CST Thu Nov 16 2017

VFR/MVFR except IFR in -shsn band that is crossing the area. A
general transition towards IFR is likely as more -shsn moves in
eventually mixing with rain by morning. Expect poor flight
conditions for the period. Timing when a particular site drops
down is difficult, so taking the pessimistic approach with lower
flight cats in this TAF package.


DLH  27  35  23  27 /  70  70  10   0
INL  24  35  18  22 /  40  30   0  10
BRD  30  38  23  28 /  30  30  10   0
HYR  30  36  27  31 /  40  80  40  10
ASX  29  38  29  31 /  70  80  30  10


LS...Small Craft Advisory until 4 PM CST Friday for LSZ140>142.



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