843 
FXUS63 KFSD 020350 AAA
AFDFSD

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Sioux Falls SD
1050 PM CDT Tue Sep 1 2020

.SHORT TERM...(This Evening through Wednesday)
Issued at 228 PM CDT Tue Sep 1 2020

A quiet Tuesday continues across the region, as mid-lvl clouds 
slowly move eastward.  Temperatures are finally beginning to rise 
behind the clouds, but weak cold advection aloft is hampering the 
warmup slightly. 

Tonight: Clear skies are expected to begin the overnight hours, 
however we could see some increasing high clouds late. Winds may 
stay mixy enough to hold temperatures warmer than expected.

Wednesday: Subtle shortwave energy moving into the Northern Rockies 
will help induce troughing over the western Dakotas early on 
Wednesday. The resultant warm air advection aloft will push warmer 
low-lvl temperatures back eastward. However, a handful of models are 
again producing a stubborn mid-lvl cloud deck, and 925 mb 
temperatures have cooled slightly over the past two days.  This is 
likely resulting in a slight lowering of high temperatures in some 
locations.  Winds may begin to gust over 20 knots at times in the 
afternoon, with dew points mixing into the mid-40s, this will push 
RH values into the upper 20 percent range.  Wildfire danger risks 
may be elevated into the early evening, but at this point a bit shy 
of red flag conditions. 

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 228 PM CDT Tue Sep 1 2020

Wednesday Night-Thursday: Models consistent in bringing a strong 
frontal boundary through the area after midnight Wednesday. Strong 
cold advection aloft will push in quickly behind the surface front. 
Feel model guidance is under forecasting the wind gust potential behind the 
front through mid-morning Thursday, with ensemble data suggesting a 
reasonable risk for 35 to 40 mph gusts at times. Have manually 
bumped up winds.   We'll have another dry day on Thursday behind the 
boundary, highs will reach into the lower to middle 70s.  Falling 
dew points combined with gusty winds may again lead to enhanced fire 
danger risks in the afternoon. 

Friday-Saturday: Medium range models aiming to push another front 
through the area on Friday which will eventually hang up to our 
south before advancing as a warm front late Saturday.  Some concerns 
forecast temperatures may be a bit too warm on Friday, and could be 
lowered slightly. Highs on Saturday will be more dependent on how 
quickly the front can lift northeast in the afternoon. There seems 
to be more focus for PoPs in the Saturday night into Sunday morning 
timeframe as a very subtle wave in the northwest flow moves through. 
 Right now, the greatest focus would be in SW Minnesota and NC Iowa.

Sunday-Tuesday: Residual warm air will lead to another near to above 
normal day on Sunday, before the first true Fall cold front works 
into the region. Cold air will begin to ooze southward Sunday night, 
with the stronger surge of cold advection on Monday.  Rain chances 
should increase into the Monday and Tuesday timeframe.  Based on 
ensemble data, could see high temperatures struggle to climb out of 
the mid-upper 50s, with some hints at a couple overnight lows in the 
30s by Wednesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1048 PM CDT Tue Sep 1 2020

VFR conditions are expected to prevail through the period. winds 
will be light and mainly westerly through early Wednesday 
morning.

Some models hint at river valley fog developing near KSUX this 
morning, but confidence is too low to include in the TAF at this 
time. Winds will increase slightly after sunrise, turning 
southwest with gusts into the 20s possible in the afternoon.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...Dux
LONG TERM...Dux
AVIATION...BP