502 
FXUS63 KFSD 050725
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
225 AM CDT Thu Sep 5 2019

.SHORT TERM...(Today and Tonight)
Issued at 225 AM CDT Thu Sep 5 2019

A warm and more humid day is ahead, with warm/moist surge ahead of 
cool front which will push across the forecast area today. Warmest 
air aloft will be found above 850mb per forecast soundings, and this 
likely will not be tapped. However, even mixing to 925-900mb should 
yield highs in the mid 80s to lower 90s. This along with pooling dew 
points in the mid-upper 60s will result in heat indices in the mid 
to upper 90s for some areas south of Highway 18 this afternoon. The 
aforementioned warm and dry layer above 850mb should prevent any 
convective activity as the front moves through, with widespread 
sunshine expected after early morning mid-level clouds exit the 
southeast parts of the forecast area. 

Front exits our eastern counties this evening, with dew points 
falling back into the mid-upper 50s most areas by late tonight. 
This along with clear skies and decreasing winds should lead to 
overnight lows also in the mid-upper 50s. Could again see some 
patchy light fog develop late tonight, mainly valley areas, but 
possibly a bit more coverage in northwest Iowa where low level 
moisture will not scour out until late evening.


.LONG TERM...(Friday through Wednesday)
Issued at 225 AM CDT Thu Sep 5 2019

A more comfortable day on Friday, with dew points back in the 50s 
and temperatures near early-September normal highs in the mid 70s to 
lower 80s. Increased rain chances still on tap for late Friday night 
into Saturday, as deep isentropic lift moves across the region ahead 
of broad upper wave sliding out of the northern Rockies. Should not 
be a total washout Saturday, as forecast soundings show lingering 
dry layer below 700mb across the area through the morning. Focus in 
the afternoon appears to shift north, near mid level front extending 
from central ND, through northeast SD/southwest MN by mid afternoon, 
which should allow southern parts of our area to dry out a bit.
 
Elongated wave lingers across the northern Plains through Sunday, 
which will keep clouds and shower chances across the area through 
the latter half of the weekend as well. Instability rather weak 
through the weekend, so thunder chances will be minimal. With the
persistent clouds/rain chances, temperatures Sunday will again be
on the cool side, from the mid 60s-lower 70s most areas.

Shortwave ridge moves across the region Sunday night, followed 
quickly by more robust trough pushing into the High Plains by late 
Monday. Severe potential looks rather low in our area at this time. 
Deep layer shear of 35-45kt could support a few organized storms, 
but instability remains on the weak side, except through parts of 
the Missouri River Valley late in the day. 

This wave slides off to the northeast Monday night, and rising 
heights aloft should limit precipitation chances, and allow near to 
slightly above normal temperatures to build back into the region for 
the end of this forecast period.


&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1029 PM CDT Wed Sep 4 2019

VFR conditions expected through the TAF period. There will be a
period of low level wind shear at KSUX early Thursday morning.


&&

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

$$

SHORT TERM...JH
LONG TERM...JH
AVIATION...JM