795 
FXUS63 KFSD 132355
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
655 PM CDT Mon Jul 13 2020

.SHORT TERM...(This Evening through Tuesday)
Issued at 342 PM CDT Mon Jul 13 2020

Warm and muggy airmass across the plains with stout southerly winds 
drawing moisture north. Cold front associated with low pressure 
along the US/Canadian border extending into central South Dakota. 
Ahead of the front, unstable atmosphere with ~2500 J/kg of ML CAPE 
above a very capped environment.  As cold front works east this 
evening, expect cap to be weakened, but thunderstorm chances will 
likely have to wait until convection associated with a short wave 
moving from western Nebraska approaches after 03Z Tuesday.  Given 
the storms will mainly be post frontal, expect storms to be elevated 
in nature. 1-6 km bulk shear values are in the 30-35 knot range, so 
expect convection to try to display organizational elements at times 
with strong winds and hail being the primary severe weather threats. 
 
Rain chances continue through the overnight into Tuesday. With 
precipitable water values near 1.5" along and behind the threat, 
potential for training storms which may result in localized flash 
flooding.  WPC has outlined much of the area in slight risk for 
excessive rainfall overnight.  

On Tuesday, expect the chance for showers and thunderstorms to 
continue.  Limited instability should keep severe weather threat 
confined to northwest Iowa where 1000-1500 J/kg of elevated CAPE is 
possible in the morning hours.  With cloudy conditions and cooler 
air moving in aloft, expect surface temperatures to remain in the 
60s to lower 70s. 

.LONG TERM...(Tuesday Night through Monday)
Issued at 342 PM CDT Mon Jul 13 2020

The remainder of the week, a warming trend is expected with 
temperatures warming into the upper 80s and 90s by Friday. Could see 
the chance of elevated nocturnal thunderstorms Friday morning as 
building warm air interacts with nose of low level jet across the 
plains. Widespread 90s are expected on Saturday, and with dew points 
in the lower 70s, heat index values of 95 to 105 may require a heat 
advisory across at least part of the area. 

A cool front is expected to move through the region Saturday night, 
but given the atmosphere is capped, am not expecting precipitation. 

Upper ridge across the area begins to break down Sunday into early 
next week as strong area of low pressure moves across central Canada 
into the western Great Lakes.  This will create increased chances of 
precipitation as short waves rotate around the upper low.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 650 PM CDT Mon Jul 13 2020

Winds will shift from southerly to northerly during the evening
and overnight hours as a frontal feature slowly moves across the 
area from west to east. With this front will come some potential
for scattered strong thunderstorms during the early AM hours. 
Storms that form overnight will be elevated, but still have 
potential for hail and gusty winds. A more widespread area of 
showers and garden-variety thunderstorms is likely from sunrise 
through the late morning associated with a larger passing weather 
system. These exit the area by mid-afternoon, with light north 
winds in their wake.

&&

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

$$

SHORT TERM...BT
LONG TERM...BT
AVIATION...VandenBoogart