154 
FXUS63 KFSD 070914
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
314 AM CST Sun Nov 7 2021

.SHORT TERM...(Today and Tonight)
Issued at 313 AM CST Sun Nov 7 2021

A somewhat tricky temperature forecast for today with current 
satellite image indicating a rather thick and widespread cirrus 
shield across the region very early this morning. All model RH time 
sections indicate these clouds pulling out of the area by 18Z, so we 
should still be able to reach our full warming potential with an 
upper level ridge overhead. One other caveat is that the NAM wants 
to develop stratus northward into the Interstate 29 corridor and 
eastward during the afternoon - which would definitely affect 
temperatures. This is not supported by other models nor SREF probs, 
so discarded this solution. Banking on a best case scenario, with 
925 and 850 mb temperatures above the 90th percentile with respect 
to climatology, we are looking at highs in the upper 60s to mid 70s. 
Winds will not be that strong today, though breezier conditions will 
exist east of Interstate 29 where winds at the top of the mixed 
layer are a little stronger.

By this evening and into tonight, a surface trough/frontal boundary 
will slide through the area. This will bring winds around from the 
north/northwest and begin to usher in cooler air. With that, looking 
at lows in the upper 30s to lower 40s.


.LONG TERM...(Monday through Saturday)
Issued at 313 AM CST Sun Nov 7 2021

With continuing cold air advection, Monday will be much cooler - 
though still just above normal for this time of year - with highs in 
the 50s. As mentioned in the previous discussion, decent midlevel 
frontogenesis develops across western and northern SD on Monday, 
though at this time models keep any precipitation out of our area. 
The ECMWF continues to be an outlier with respect to bringing light 
precipitation to the area later on Monday night into early Tuesday 
with a weak shortwave, though discarded that solution with little 
support from other models. Otherwise, Tuesday looks dry with surface 
ridging building into the area. Highs will again be in the 50s.

Still seeing some model differences with respect to the 
Wednesday/Thursday system, though both the GFS and ECMWF are 
beginning to come together on northern and southern stream energy 
within a deepening upper level trough over the central CONUS phasing 
to the east of our area. While the specifics still need to be worked 
out, the general theme at this point is for rain to develop over our 
area sometime on Wednesday, pulling eastward by Thursday, then 
perhaps receiving a little bit of light snow on the backside of the 
system on Thursday night. Again, it is worth repeating that there 
remains much uncertainty, as evidenced by the wide spread of QPF 
solutions within the GEFS plumes for that time period - with some 
clustering on the lower end of QPF amounts. With a rapidly deepening 
surface low progged to our east on Thursday into Friday, it looks 
like a windy period for the end of the week. Both deterministic 
models and ensembles support much cooler temperatures for Friday and 
Saturday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1026 PM CDT Sat Nov 6 2021

VFR conditions are expected through the night and into Sunday.
Cirrus will remain rather thick through the morning hours, with
winds slowly increasing from the south. 

There remains an outside chance of a bit of valley fog overnight,
but probabilities remain low in most of the evening guidance given
the cloud cover. 


&&

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

$$

SHORT TERM...JM
LONG TERM...JM
AVIATION...Dux