Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 210521
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1121 PM CST Mon Nov 20 2017

.UPDATE...
Issued at 929 PM CST Mon Nov 20 2017

Strong winds continued to progress east this evening with gusts to
38 knots recently at KINL and 31 knots at KBRD. Strong cold air
advection, pressure rises and steepening low level lapse rates
will promote continued strong winds tonight into Tuesday morning.
The winds will be strongest with gusts around 45 mph possible,
just after frontal passage. We increased gusts a bit tonight and
increased the chance for snow showers further south...but little
accumulation is expected.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 347 PM CST Mon Nov 20 2017

Main focus for this period is the dramatic cool down and breezy
winds for tonight. Lows will be in the mid to upper teens across the
International Border and Arrowhead region while temperatures remain
in the low twenties across northwestern Wisconsin. Wind chills in
northern Minnesota will be around zero degrees.

A potent low pressure system will move from southern Manitoba east
to eastern Ontario tonight, skating just north of the US/Canadian
border.  Behind this system a cold front will surge through the
forecast area this evening.  On the back side of this system there
will be a very tight pressure gradient, along with a steep pressure
rise maxima that moves across far northern Minnesota.  This will
produce strong northwest winds behind the cold front overnight
tonight and Tuesday morning. Winds will increase to 15 to 25 mph,
with gusts of 35 to 40 mph. Gusts could approach 45 mph in the
Brainerd Lakes region.

A chance of snow showers and flurries across the International
Border and Arrowhead starting later this evening and continuing on
till mid-morning. New snowfall accumulation under an inch. With
winds turning from the northwest, there is considerable fetch across
Lake Superior for lake effect snow across portions of the south
shore, particularly Ashland and Iron County with new snowfall
accumulation of up to half an inch.

.LONG TERM...(Tuesday night through Monday)
Issued at 347 PM CST Mon Nov 20 2017

Chilly temperatures continue as a few arctic air intrusions move
through the region, with a decent shot of precipitation Friday and
Saturday morning.

Tuesday night and Wednesday will have a period of mostly clear
skies, especially over our southern counties, due to a surface
high pressure ridge that translates through the region. Clouds
should increase from the west by the afternoon as an increase in
850-700 mb layer warm air and moisture advection moves back into
the region, due to southerly return flow on the westward side of
the ridge. There is a chance of some light snow along the push of
warmer air, mainly over our western counties, and progressing
eastward by Wednesday evening. There`s some uncertainty regarding
whether snow will actually accumulate. Even if some accumulating
snow does fall, QPF amounts look be very light. Temperatures
Wednesday will remain cold, with highs in the 20s across the
Northland.

Thursday and early Friday morning look dry as another high pressure
system moves across the region. A fairly potent Alberta clipper
system is progged to dive east-southeast over southern Canada on the
heels of the high pressure system, which could impact Thanksgiving
travel conditions for Friday. Right now, there appears to be a
pretty good punch of warmer air ahead of the clipper system, thanks
to southerly flow and 925 mb temperatures between 4 to 7 degrees
above freezing, which is quite warm for this time of the year. P-
types with this system should be snow initially, transitioning to a
rain/snow mix by mid-morning, and to mostly rain by the afternoon,
transitioning back to snow by Friday night. Temperatures Friday
could reach nearly ten degrees above seasonal average, with highs
ranging from the upper 30s over the Arrowhead, into the middle 40s
to the south. However, temperatures will tumble back down for
Saturday once the clipper departs. Cold air advection will bring 925
mb temperatures of 5 to 12 below zero by Saturday morning - quite a
contrast from that of Friday afternoon! Overnight lows Saturday
morning could drop back into the middle teens north to the middle
20s south. West to northwest winds could be fairly gusty as the
clipper passes to the north.

For Saturday through Monday, chances of precipitation will primarily
be isolated to the Lake Superior snow belt as colder 850 mb
temperatures and on-shore flow should lead to chances of lake effect
snow Saturday and Sunday. Temperatures continue to be either near or
below seasonal averages, with highs mainly in the 20s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1121 PM CST Mon Nov 20 2017

A strong cold front continued to move through the Northland this
evening with strong gusts of 30 knots to 40 knots progressing east
through northeast Minnesota. MVFR ceilings were moving southeast
behind the front and low pressure system. Recent radar shows
precipitation from northwest Ontario into parts of northeast
Minnesota. Snow showers will be possible tonight, most likely at
KINL/KHIB. There may be some breaks in the MVFR ceilings that
develop Tuesday morning but with cold air aloft, we expect most
areas to see them redevelop through the day. High pressure will
start to nose in from the Northern Plains late in the TAF period
causing the MVFR ceilings to lift and become scattered.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  19  23  10  25 /  20  10   0  10
INL  15  20   7  22 /  60  20  10  20
BRD  21  24  11  27 /  10   0   0  40
HYR  22  26  11  28 /  10  10   0   0
ASX  24  27  16  29 /  30  40  10   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Gale Warning until 4 PM CST Tuesday for LSZ121-140>148.

&&

$$

UPDATE...Melde
SHORT TERM...LE/WM
LONG TERM...JTS
AVIATION...Melde


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