584 
FXUS63 KFSD 060824
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
324 AM CDT Wed Oct 6 2021

.SHORT TERM...(Today and Tonight)
Issued at 323 AM CDT Wed Oct 6 2021

Latest satellite imagery reveals a stratus deck just to our east 
starting to advect over portions of NW Iowa and SW Minnesota, with 
current temperatures across the region hovering in the 50s. Though 
trends do suggest this stratus should continue to wane as we 
approach daybreak, will likely see diurnally driven cu develop in 
its place as a decent moisture layer lingers in the atmosphere. 
Thus, with more cloud cover in place have nudged afternoon highs a 
touch cooler, especially in areas east of I-29. Much like yesterday, 
winds during this time will also remain out of the south/southeast, 
with gusts as high as 20 mph possible in areas west of I-29 during 
the afternoon hours.

Should see any breezy conditions gradually subside near sunset, with 
winds forecast to remain out of the southeast during the overnight 
period. Latest HREF guidance continues to hint that fairly 
widespread fog may be possible prior to daybreak Thursday in areas 
east of I-29, however, this will largely depend on how much clearing 
we see. As of now, believe clearing will be much slower than 
guidance is suggesting, which would help to limit such development. 
So for the time being will continue to monitor trends and refine the 
forecast during the next package if adjustments are needed. 
Otherwise, expect overnight lows to remain fairly mild as 
temperatures only fall into the mid to upper 50s. 

.LONG TERM...(Thursday through Tuesday)
Issued at 323 AM CDT Wed Oct 6 2021

Expect similar conditions to prevail Thursday, with winds becoming a 
touch more southerly throughout the day. While conditions look to 
remain largely dry, can't rule out the possibility of seeing a few 
light showers and rumbles of thunder in areas east of I-29 as an 
upper level low near Missouri lifts northward toward the region. 
Much like the previous discussion alluded to, sounding profiles 
continue to show elevated skinny CAPE, suggesting that the overall 
severe threat should remain low. 

Upper level flow turns more southwesterly by Friday as a trough digs 
across the western CONUS. At the sfc, expect winds remain out of the 
south under mostly sunny skies, allowing afternoon highs to climb 
into the upper 70s to low 80s with the aid of WAA. Overnight lows 
during this time will also remain on the mild side, as temperatures 
only fall into the mid to upper 60s.

Friday night into Saturday, expect the aforementioned trough and its 
associated sfc cold front to edge closer to the region, causing rain 
chances to once again return to the forecast. While most guidance 
continues to suggest that the better moisture axis will remain just 
to our west and north, still believe we stand a fairly good chance 
for seeing light showers throughout the day, especially in areas 
north of I-90. Still have a bit of time to iron out the overall 
severe threat, but certainly think the possibility for seeing 
thunderstorms does exist. One other thing to watch once confidence 
in timing and location of the wave increase will be winds. The 
northwest flow should be fairly stout if something closer to the 
GFS/Canadian pans out.

Otherwise, expect largely dry conditions to prevail for the 
remainder of the weekend, with northwest flow forecast to enhance 
CAA across the region. As a result, have afternoon highs in the 60s 
to low 70s becoming more common through early next week, with 
overnight lows falling into the 40s. Could see rain chances return 
to the forecast by Tuesday as an upper level low near the four 
corners ejects northeastward, however, there is still quite a bit of 
uncertainty concerning the overall track of this feature. 
Nonetheless, will continue to monitor trends in the coming days. 

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1041 PM CDT Tue Oct 5 2021

Stratus approaching Hwy 71 corridor from KSLB-KSPW as of 0330Z
still largely VFR with ceilings 3500-4000ft AGL, with hints of
thin moisture layer as far west as KSXK-KSHL with reports of 
cloud layer, though nothing apparent on satellite imagery. Still 
looking for ceilings to lower into MVFR range as stratus expands 
westward into northwest Iowa/southwest Minnesota overnight into 
early Wednesday, but potential for IFR ceilings seems less likely.
Diurnal heating should allow any MVFR ceilings to rise back into
the lower VFR range as any strato cu approaches I-29 corridor by 
midday, so will stick with 3500-4000ft BKN clouds for KFSD/KSUX 
during the afternoon, with western edge of this cloud shield
expected to clear with loss of heating by 07/00Z.

Could possibly see patchy fog on the western edge of the advancing
stratus tonight/early Wednesday, but latest high res models have 
been backing off on this potential with visibility trending higher
in recent runs.


&&

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

$$

SHORT TERM...SST
LONG TERM...SST
AVIATION...JH