Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 121733
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1233 PM CDT Thu Oct 12 2017

.SHORT TERM...(Today through Friday)
Issued at 341 AM CDT Thu Oct 12 2017

The Northland will remain under a southerly flow regime, which will
enhance 850-700 mb layer warm air and moisture advection today.
There is a shallow saturated layer (a depth of ~4500 feet), evident
in NAM and RAP model soundings, which will support some drizzle
this morning. As of 3 AM CDT, light drizzle was observed in the
Duluth area. This will continue at least through the early morning
hours before dissipating as the saturated layer shrinks in depth.
Persistent southerly on-shore flow over the North Shore will
support some lingering drizzle over the Minnesota Arrowhead, as
well as some patchy fog along the higher elevations of this
region this morning. The Northland will see mostly cloudy skies
this morning, which should linger over our eastern counties
through the day. There could be some peeks of sunshine briefly
over the western counties later this morning and into the early
afternoon before clouding over again later this afternoon and
evening. South winds will be a bit breezy today as well, due to a
35 to 40 kt low-level jet moving into the region today. As the
boundary layer mixes, some of these stronger winds aloft could be
mixed down to the sfc. Gusts today will range from 15 to 25 kts,
with the strongest gusts expected from the Brainerd Lakes north
towards International Falls, as the low-level jet will be
strongest over these areas. Highs today will range from the
middle 50s over the Minnesota Arrowhead region, into the lower 60s
west.

A sfc cold front boundary is then progged to advance eastward
through the region tonight, which will support another round of
drizzle, and perhaps some rain showers mainly over the
International Border and Minnesota Arrowhead regions. Any
precipitation amounts will be small due to a lack of deeper
moisture. Chances of drizzle will expand over northwest Wisconsin
overnight as deeper saturation develops, per the NAM model
soundings. This activity will progress eastward as the frontal
boundary moves through Friday morning. There could be some
lingering chances of showers/drizzle over north-central Wisconsin
Friday afternoon, but most of the Northland should be under partly
to mostly sunny skies Friday morning and afternoon, thanks to
decreasing 1000-850 mb layer moisture. Temperatures will be
slightly cooler due to the cold air advection behind the front.
Highs Friday will range from the lower 50s over north-central
Minnesota into the upper 50s over northwest Wisconsin.

.LONG TERM...(Friday night through Wednesday)
Issued at 404 AM CDT Thu Oct 12 2017

Saturday through Sunday, our next weather maker will affect the
area. A large upper level trough moves out from the Rockies across
the high plains Saturday and across the Northland Saturday night
before ejecting to our east on Sunday. The surface low develops
over Iowa sometime on Saturday, then tracking northeast across
Wisconsin and on to eastern Ontario. The models are still in poor
agreement on this storm, the most noticeable difference being the
timing and track of the surface low. The GFS and ECMWF are
noticeably faster in developing it over Iowa on Saturday afternoon
before sweeping it rapidly off to the northeast. The NAM is much
slower and is weaker, and eventually tracks farther north and
brings precipitation into the forecast area roughly 6 hours later
than the GFS and ECMWF. The ECMWF and GFS have been trending
faster over the last few runs, their earlier runs agree more with
the current NAM. For now have left the consensus forecast alone,
as it at least brings some precipitation chances into the area
Saturday afternoon, but I generally prefer the faster solutions
for now, and would not be surprised to see that the pops for
Saturday are increased in the next few forecast cycles. On the
northern side of this storm system there is enough cold air aloft
for precipitation to begin as snow aloft, with the main question
being whether it will melt before it reaches the ground. Bias
correction lately has brought temperatures down, and with the
cloud cover that is not going to be appropriate, and have kept min
temps above freezing overnight. This reduces our snow potential
somewhat, and between that and the warm ground, it is going to be
hard to get any accumulations early Sunday morning. Several
models are producing a few inches of snow accumulation, but these
appear to be using a climatology or thickness depth calculated
SWE, and are likely too high and have ignored them. So, expect
that while we are likely to see snow flying through the air,
accumulations are unlikely, and most definitely not on the roads,
which are quite warm.

With all the differences in the models over the weekend, it is hard
to have much confidence in the later periods, but for now, the
early parts of next week should be dry with temperatures slowly
warming through the middle part of the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1227 PM CDT Thu Oct 12 2017

Expansive area of MVFR stratus with embedded IFR along the north
shore including KDLH. To the west VFR is slowly progressing
eastward, but any improvement will be short lived as a short wave
brings lower flight cats back overnight with spotty dz/-ra.
Conditions should improve Friday morning to MVFR and to VFR by
midday.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  58  46  55  36 /  30  30  10   0
INL  62  39  52  29 /  10  20   0   0
BRD  62  44  56  35 /  10  10   0   0
HYR  60  49  58  35 /  20  30  10   0
ASX  61  50  59  35 /  10  20  10   0

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 11 AM CDT Friday for LSZ140-141.

&&

$$

UPDATE...LE
SHORT TERM...JTS
LONG TERM...LE
AVIATION...JW



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