Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 190921

Area Forecast Discussion
National Weather Service Sioux Falls SD
321 AM CST Sun Nov 19 2017

.SHORT TERM...(Today and Tonight)
Issued at 319 AM CST Sun Nov 19 2017

A Pleasant late fall day is expected across the region, as surface
high pressure expands over the southern and central Plains. Skies
will be mostly sunny to partly cloudy as scattered cirrus tracks
through the area. South southwest winds will be relatively light at
less than 15 mph, leading to above average afternoon highs in the
mid 40s to mid 50s. Light southerly winds and mostly clear skies
continue into the overnight hours. Lows will reach the mid 20s to
near 30.

.LONG TERM...(Monday through Saturday)
Issued at 319 AM CST Sun Nov 19 2017

Monday will feature a taste of early fall weather with temperatures
10 to 20 degrees warmer than normal. West to southwest winds will
bring warmer air ahead of a dry cold front. Have bumped highs a few
degrees by blending between Superblend and CONSMOS. Highs could
reach the upper 50s to near 60 west of the James river. It would be
one of the warmest days of the week, but questions are how much
cloud cover will impact high temperatures as models bring mid to
high clouds through the day.

The dry cold front will drop south across the area Monday evening
into the overnight hours, resulting in a big change in temperatures.
Cooler air builds in behind the front keeping highs in the 20s and
30s. A tightening pressure gradient will keep the wind machine on
with brisk northwesterly winds mainly in the morning.

Northwesterly flow aloft will continue to bring embedded waves
across the area. One of the upper waves and associated front will
pass close of the forecast area by Wednesday. This system could
bring very light rain or snow/flurries north of I-90. There is
uncertainty in terms of location between models. The GFS and
Canadian keep the core of the system further north, while the ECMWF
brings more precipitation chances to the area. Models also indicate
some low-level moisture; therefore will keep the probability of
precipitation on the lower side.

Thanksgiving Day looks quiet and pleasant with light winds and
warmer than normal temperatures. Friday will feature even warmer
temperatures across the High Plains. Models continue indicating very
warm 925mb and 850 mb layer. Given that and warm westerly flow, have
increased highs by a few degrees using a blend of the guidance and
the ADJMEX to produce highs in the upper 50s.

The remainder of the extended bring cooler temperatures compared to
previous days. Uncertainty arises with precipitation chances through
the weekend as several shortwaves slide to the area. Left just small
PoP chances due to low confidence in timing and placement between


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1017 PM CST Sat Nov 18 2017

VFR conditions are expected through the TAF period.




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