Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 011220 AAA

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
720 AM CDT SAT OCT 1 2016

Issued at 720 AM CDT Sat Oct 1 2016

Please see the updated 12Z Aviation Discussion below...


.SHORT TERM...(Today through Sunday)
Issued at 419 AM CDT Sat Oct 1 2016

The cut off upper low over the Lower Ohio river valley early this
morning, along with a weak ridge axis extending over northern
Minnesota will remain in control of  weather for the Northland
through the weekend.  The upper low will gradually move north across
Indiana today, then slowly ease northeast into far southeast Ontario
by Sunday afternoon. This low is going to do little more than
bring some mid and high clouds to the eastern sections of the
forecast area through Sunday, with some small rain chances for
Price county. Stratus that has developed over the area downstream
of Lake Superior the last few mornings is here once again, with
the relatively warmer -mid 50s- lake modifying the airmass that is
in the mid 40s where the clouds are clear. Expect this behavior
once again tonight, with stratus developing over the head of the
lake and over the Bayfield Peninsula in the lee of the light east
to northeast flow over the lake. The signal is not as strong as it
was the last two nights, but the pattern is about the same, and
there really hasn`t been significant change in the airmass, so it
seems best to assume the stratus will form again. The similar
airmass and only small changes in cloud cover should favor a
persistence forecast in temperatures, with highs both days getting
into the middle and upper 60s and upper 50s/low 60s near the lake.
Onshore flow is weaker on Sunday so it should be a little warmer
near the lake then. Lows to be very similar as well, dipping into
the low 40s where it clears out, with mid and upper 40s under the
cloud cover.

.LONG TERM...(Sunday night through Friday)
Issued at 419 AM CDT Sat Oct 1 2016

Sunday evening continues the long-awaited departure of the
stagnant cut-off low. By 03.00Z, that feature is forecast to be
over the eastern Great Lakes and progressing eastward with time.
Farther to the west, a high pressure ridge will be positioned over
the Plains and the Upper Midwest. A weak shortwave trough is
forecast to move across the northern Canadian Prairie Provinces
overnight and early Monday. Surface high pressure over the western
Great Lakes, with the transient low to the north, will continue
the development of a southerly return flow across the region
Sunday night into Monday.

The upper-level ridge will advance eastward ahead of a deepening
longwave trough digging across the western United States by Monday
night. A cold front will push across the Dakotas and into western
Minnesota overnight with increasing cloud cover and rain showers
spreading east toward the Northland. Tuesday afternoon through
Wednesday evening appear quite soggy with and area of rain, and a
few embedded thunderstorms, slowly moving eastward ahead of the
decelerating cool front. Twenty-four hour rainfall of 1 to 2
inches seems likely for the eastern two-thirds of my CWA.

Differences in the deterministic and ensemble guidance increase
after Wednesday. The variety of solutions for the track and
intensity of Hurricane Matthew, and the resultant quasi-Rex Block,
produce a wide spread of sensible weather for the area. The
deterministic GFS brings the closed upper low slowly northeastward
into southern Manitoba by Thursday morning with most of the GEFS
members farther west. The ECMWF and GEM both feature a more
progressive solution with the ECMWF opening the low back into a
trough. Prefer the slower GFS solution and nudged the consensus in
that direction.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 720 AM CDT Sat Oct 1 2016

Low stratus and fog developed over western Lake Superior and
drifted across northwest Wisconsin and northeast Minnesota
overnight. The HRRR and RAP models have been doing a good job
handling the low-level moisture overnight and yesterday, so have
trended the ceilings and visibilities similar to that guidance.
Expect the low stratus and fog to lift gradually this morning,
with visibilities improving first, followed by ceilings.
VLIFR/IFR categories are expected early today, improving to VFR
for all sites by late morning/early afternoon. Light winds and
little cloud cover should be conducive for MVFR fog once again
tonight. DLH is the notable exception to this trend, with fog and
low stratus forecast to develop over the lake and move inland
after 02.03Z. Confidence for this forecast package is average.
Visibilities and ceilings may lift faster than currently forecast
this morning.


DLH  63  45  65  46 /  10   0   0   0
INL  66  49  69  48 /   0   0   0   0
BRD  68  46  69  49 /   0   0   0   0
HYR  69  44  67  44 /   0   0   0   0
ASX  62  47  64  44 /   0   0   0  10


.DLH Watches/Warnings/Advisories...


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