Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 272204
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
404 PM CST Sun Nov 27 2016

.SHORT TERM...(This evening through Monday)
Issued at 403 PM CST Sun Nov 27 2016

Fog and clouds have been the main concern in the very short term
this afternoon and evening.  We have warm moist air being advected
into the area over the top of our existing snow, and it is causing
the fog and low clouds over large portions of the forecast area.
Places with less snow have had a greater increase in visibility this
afternoon, so you can see almost exactly where our heavy snow band
was just over a week ago.  I expect cooling temperatures to cause
the visibilities to lower once again this evening, but perhaps not
quite as low as they were before with the higher cloud coming to
help dampen the cooling trend.  I have cancelled some counties out
of the advisory this afternoon based on latest trends, but I may
have overdone it if the cloud cover isn`t quite thick enough and
advisory may need to be expanded again.

This is all in advance of the storm system that has been
developing out over the plains all day, with a strong upper low
over western Nebraska this afternoon and the surface low is
developing nicely over the CO/NE/KS corner area. The upper low
becomes slowly cut off as it moves northeast into South Dakota by
overnight tonight, with a surface low deepening and moving to
eastern South Dakota. The strong wave of warm moist advection,
isentropic lift and frontogenesis moves across the area overnight
tonight bringing a wave of precipitation across the forecast area.
Have kept pops in this band very high overnight. Monday the entire
system becomes stalled over eastern North Dakota and northwest
Minnesota as the upper low gets even more cut off, and it wraps
some dry air around the southern side and into our southeastern
counties during the daytime. Have kept pops fairly high closer to
the upper low, but with the dry air wrapping in have lowered pops
over my northwest WI counties. This also brings some instability
into my southeast, and have included some potential for thunder
during the day as well. Precipitation on Monday will be pretty
showery in nature with the instability nearby. Dry slotting may
keep the east almost dry tomorrow. Temperatures to be nearly
steady overnight tonight with the warm air advection going on, but
should rise in the warm sector tomorrow for even more melting in
the rain.

.LONG TERM...(Monday night through Sunday)
Issued at 403 PM CST Sun Nov 27 2016

The upper level low pressure system will essentially park itself
over the Minnesota and Wisconsin area from Monday night through
Wednesday, before finally pulling off to the east for the end of
the work week. The presence of the upper low and resultant
associated moisture will result in a prolonged period of
precipitation for nearly all of the work week. While most of the
daytime precipitation looks to be in the form of rain, we could
see a transition to some light snow, especially at night. Overall,
it will be a mild start to the week, but temperatures are
gradually expected to settle into more normal readings for the
middle to end of the work week. The highest POP`s will be during
the first part of the week, with the system maintaining the most
moisture at the onset of the development of the closed low. As the
week wears on, we should see POP`s drop into the chance range, and
then essentially dry out by Friday. High temperatures will range
from the mid 30s to lower 40s early in the week, and then
gradually drop into the upper 20s to middle 30s as the week wears
on.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1151 AM CST Sun Nov 27 2016

Another tough forecast for the Northland TAF sites this afternoon,
with widespread dense fog hanging tough in many areas. A hole in
the clouds had developed across northwest Wisconsin, with clear
skies at KHYR as of 18Z. There was also some modest improvement at
KBRD and KINL, with VLIFR at KDLH and KHIB. The big question is
how much improvement there will be for the remainder of the
afternoon. The HRRR indicates we may not see much, if any
improvement, especially at KDLH, with persistent east flow. KDYT
only has a CIG of 300 feet, and that would indicate we would have
a tough time of seeing much improvement. HRRR maintains 1/4 mile
VSBY at KDLH into the night, before incoming rain starts to
improve VSBY`s across much of the area. To make a long story
short, we will maintain VLIFR at KDLH and try to bring some
improvement elsewhere. With rain moving rapidly in from the south
and west tonight, we will continue to see low clouds, but probably
see some improvement in VSBY. Since there is no airmass change
through the TAF period, once the rain lets up, we will probably go
right back down in fog. East winds will increase markedly through
the night, especially at KDLH. We may also see a few thunderstorms
on Monday, especially by afternoon.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  34  44  36  39 / 100  60  60  30
INL  31  42  36  40 /  90  80  60  60
BRD  35  45  33  39 / 100  50  40  40
HYR  36  45  35  40 / 100  50  50  30
ASX  35  47  39  43 / 100  50  50  30

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Dense Fog Advisory until 9 PM CST this evening for MNZ025-
     033>037.

     Dense Fog Advisory until midnight CST tonight for MNZ012-018>021-
     026.

LS...Small Craft Advisory until 4 AM CST Tuesday for LSZ121-146>148.

     Small Craft Advisory until 4 AM CST Tuesday for LSZ142>145.

     Small Craft Advisory until 1 AM CST Monday for LSZ140-141.

     Small Craft Advisory from 7 AM Monday to noon CST Tuesday for
     LSZ140-141.

     Gale Warning from 1 AM to 7 AM CST Monday for LSZ140-141.

&&

$$

SHORT TERM...LE
LONG TERM...DAP
AVIATION...DAP



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