502 
FXUS63 KFSD 160911
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
411 AM CDT Thu Jul 16 2020

.SHORT TERM...(Today and Tonight)
Issued at 409 AM CDT Thu Jul 16 2020

Current satellite imagery shows quiet conditions across the region 
with a bit of valley fog forming along and south of Sioux City. 
Visibilities are generally 1/2 to 2 miles where it is occurring, and 
given the clear skies and calm winds in place, could see a bit more 
fog develop over the next few hours. Otherwise, expect mostly sunny 
skies and S/SW winds to prevail throughout the day as sfc high 
pressure controls the region. As we head into the late 
afternoon/evening hours, a weak shortwave will lift over NE Nebraska 
and graze portions of SE South Dakota. While overall moisture 
content looks rather limited, can't completely rule out the 
possibility of seeing isolated to scattered showers along and west 
of the James River. While there is decent instability in place 
(~2000 J/Kg), the atmosphere remains largely capped and shear 
profiles remain marginal at best. Soundings also show lapse rates 
around 7 deg C/km where convection could develop, which should limit 
available energy for thunderstorms. Thus, the overall severe threat 
remains low at this time.


.LONG TERM...(Friday through Wednesday)
Issued at 409 AM CDT Thu Jul 16 2020

There will continue to be a chance of isolated to scattered 
storms into Friday morning along and east of I-29 as the 
aforementioned shortwave continues to push eastward. However, 
given the quick moving nature of this feature coupled with the 
limited moisture in place, am not expecting much in the way of 
measurable precipitation. Much like Thursday, winds throughout the
day Friday will largely remain out the of S/SW and could become a
bit breezy, with gusts up to 30 mph possible at times. Given the 
enhanced WAA across the region, expect temperatures to climb into 
the upper 80s to low 90s, with dewpoints in the low to mid 70s. As
a result, heat index values look to approach the upper 90s to low
100s. 

Another shortwave looks to graze by just north of the region Friday 
night. At this time, the best chances for seeing showers/storms will 
likely be along and north of Hwy 14. While SPC's current Day 2 
Outlook outlines both a Marginal and Slight Risk for severe storms 
across our area, this will largely depend on if storms can initiate 
this father south, as the best dynamics and forcing remains more to 
our north.

Another hot day is in store Saturday as 850 mb temperatures from the 
NAEFS push near or above the 98th percentile of climatology. Baring 
any convective contamination from Friday night's storms, heat index 
values near or above 100 for a good chunk of our area along/south of 
I-90 look to necessitate some sort of heat headline in the future. 
As we head into the evening Saturday, expect rain chances to 
gradually return as a cold front encroaches upon the region. Some 
much needed relief from the heat will come Sunday as temperatures 
behind the front only rise into the low to mid 80s. Should see these 
temps stick around for a few days as we start the new week before 
they gradually rebound back into the upper 80s by Thursday. 
Otherwise, expect occasional chances for precipitation for the 
remainder of the extended period as multiple weak shortwaves graze 
the region.


&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1031 PM CDT Wed Jul 15 2020

Patchy fog will be possible across northwest Iowa early Thursday
morning. Diurnal thunderstorms are possible in the vicinity of 
the James River after 20Z. This activity should diminish towards
02Z Friday.  


&&

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

$$

SHORT TERM...SSC 
LONG TERM...SSC 
AVIATION...BT