Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 141111
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
511 AM CST Sun Jan 14 2018

.SHORT TERM...(Today and Tonight)
Issued at 359 AM CST Sun Jan 14 2018

The warm advection that lead to light snow showers along the
Missouri River Valley this morning has set the area up for a
relatively mild start to the day, with temperatures in the upper
teens to 20s for most. This will quickly change by tonight as a
robust upper level shortwave trough pulls a cold front south
through the region this afternoon and evening.

Snow associated with this cold front is likely to start during the
early afternoon hours for the tri-state area. There is not a ton of
moisture to work with for this front, but high-resolution model
guidance is nearly unanimous in the strong dynamics squeezing out
several tenths to an inch of snow by the evening hours as the front
passes. Once snow stops, winds will be quick to pick up and switch
to northwesterly. A strong pressure gradient leads to north winds of
20 to 30 mph by late evening, gusting into the 30s. This will cause
the light new snow to blow around, leading to areas of reduced
visibility.

.LONG TERM...(Monday through Saturday)
Issued at 359 AM CST Sun Jan 14 2018

Overnight into Monday morning, north winds continue to advect in an
impressively cold arctic air mass leading to a frigid start to the
work week. By sunrise Monday, wind chill values will be in the
negative 20s and 30s area-wide, as steady north winds continue to
blow. Wind Chill Advisories have been issued to highlight this
threat. Given the continuing wind, even the daylight will do
little to change the bitter cold conditions. Mid-afternoon
temperatures remain in the negative single digits, and wind chills
stay in the negative 20s.

Tuesday morning will be a near repeat of Monday morning, and despite
slightly reduced winds, wind chills values will likely be a bit
colder yet, since actual air temperatures drop into the negative
teens. Wind Chill Warnings highlight the coldest areas during this
period. By late afternoon Tuesday conditions are expected to slowly
begin improving, with calming winds and temperatures inching above
zero.

Mid-week onward, temperatures will improve notably, with light
southwest winds helping us reach seasonal norms on Wednesday, and
above normal readings on Thursday and Friday. This quiet period
looks to be without measurable precipitation. Next weekend the upper
level ridge responsible for large scale subsidence and the warm-
up moves east. More active weather is possible next weekend as
another trough moves through the Northern Plains. However, this is
very low confidence at this point, with models struggling to
handle position and timing of any shortwaves.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 509 AM CST Sun Jan 14 2018

MVFR conditions will be widespread throughout most of the period
with some brief IFR conditions possible in snow and blowing snow
from about 20z through 2z this afternoon and evening. Northwest
winds will gust to 35 mph at times during the late afternoon and
nighttime.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Wind Chill Advisory from 3 AM Monday to noon CST Tuesday for
     SDZ038-050-052>054-057>061-063>071.

     Wind Chill Warning from 6 PM Monday to noon CST Tuesday for
     SDZ039-040-055-056-062.

     Wind Chill Advisory from midnight tonight to 6 PM CST Monday for
     SDZ039-040-055-056-062.

MN...Wind Chill Warning from 6 PM Monday to noon CST Tuesday for
     MNZ071-072-080-081-089-090-097-098.

     Wind Chill Advisory from midnight tonight to 6 PM CST Monday for
     MNZ071-072-080-081-089-090-097-098.

IA...Wind Chill Advisory from 3 AM Monday to noon CST Tuesday for
     IAZ012>014-020>022-031-032.

     Wind Chill Warning from 6 PM Monday to noon CST Tuesday for
     IAZ001>003.

     Wind Chill Advisory from midnight tonight to 6 PM CST Monday for
     IAZ001>003.

NE...Wind Chill Advisory from 3 AM Monday to noon CST Tuesday for
     NEZ013-014.

&&

$$

SHORT TERM...VandenBoogart
LONG TERM...VandenBoogart
AVIATION...08



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