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fxus63 kfsd 202120 

Area forecast discussion
National Weather Service Sioux Falls South Dakota
320 PM CST Wed Nov 20 2019

Short term...(this evening through thursday)
issued at 319 PM CST Wed Nov 20 2019

A developing upper level shortwave over eastern Colorado will lift to the
northeast overnight, being situated over eastern Iowa by Thursday
morning. Light rain will begin to develop by this evening as
midlevel Theta E advection increases out ahead of the wave, and may
actually have a period of drizzle, especially over the western
portions of the cwa, through mid evening with mid level dry air in
place across the region. By late evening into the overnight hours,
lift begins to increase, most notably over northwestern IA, as the
shortwave tracks through eastern NE into western Iowa. With increasing
midlevel frontogenesis, rainfall will pick up from the lower MO
river corridor into northwestern IA, where a quarter to just over
half an inch of rainfall could occur overnight. Back to the
northwest where forcing is less, only a few hundredths to around a
tenth of precipitation is expected. Colder air will begin to be
pulled in behind the system, beginning in our west just after 06z,
then slowly work eastward into Thursday morning. Not expecting long
duration snowfall in any one place, with precipitation winding down
from west to east as thermal profiles cool, so anticipate snowfall
accumulation to be less than an inch across the entire area. With
increasing cold air advection, along with a steeping surface
gradient as the surface low tracks through western Iowa overnight,
northwesterly winds will pick up, gusting to around 30 kts by
Thursday morning. Lows tonight will range from the upper 20s to
lower 30s.

After some lingering light snow east of I-29 on Thursday morning,
improving conditions will be seen by later in the day as the system
pulls away and a surface ridge begins to build eastward into the
region. Clouds will decrease by afternoon with winds slowly
diminishing. It will be a much colder day with highs only in the

Long term...(thursday night through wednesday)
issued at 319 PM CST Wed Nov 20 2019

With the departure of thursdays system, there looks to be another
relatively prolonged period of dry conditions, with no precipitation
expected for Friday through the weekend. There will be some slight
moderation in temperatures on Friday as a southerly flow returns to
the region behind the exiting high pressure, with highs into the
upper 30s to lower 40s, then into the lower to mid 40s on Saturday.
The better warming will come in on Sunday as highs climb into the
mid 40s to lower 50s.

Into next week, confidence becomes low for the period Monday through
Wednesday with a myriad of model solutions through midweek. Various
solutions suggest at least the potential for a more significant
system into the Holiday period, but if/when/where remains the big


Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 1040 am CST Wed Nov 20 2019

Gradually lowering ceilings by late afternoon, with drizzle/light
rain developing by mid evening. More significant rain will
overspread the area by late evening into the overnight hours with
ceilings falling into the MVFR/IFR range. Rain will briefly change
to light snow from west to east later tonight into Thursday
morning with reduced visibility in a heavier snow shower.
Accumulations are expected to be generally less than an inch.
Northwesterly winds will begin to ramp up tonight, gusting around
30 kts at times.


Fsd watches/warnings/advisories...
South Dakota...none.


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