271 
FXUS63 KFSD 031648
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1148 AM CDT Sat Aug 3 2019

.SHORT TERM...(Today and Tonight)
Issued at 407 AM CDT Sat Aug 3 2019

A band of heavy rain has developed overnight extending from Yankton 
county northward into Hutchinson county, with radar estimates of 2- 
4 inches of rainfall around the Yankton area. With strong moisture 
transport into the western portion of our CWA, low level 
convergence, and model soundings continuing to indicate a deep warm 
cloud layer, any convection that develops will have the potential to 
produce heavy rainfall through at least mid to late morning, with 
the greatest threat remaining over the lower James River 
Valley/central MO River Valley. Hi-res CAMs have been playing catch 
up through most of the night, generally having QPF output too far 
west in comparison to reality, though all continue to point to a 
threat of scattered convection even into the afternoon for areas 
mainly west of Interstate 29. There will continue to be decent 
forcing through the early part of the day as the mid level shortwave 
continues to drift to the east, and upper level divergence is 
supplied by a jet max streaming from southwestern SD into eastern 
NE. By afternoon, forcing begins to weaken, so shower/isolated 
thunderstorm activity is expected to wane. Presently forecasting 
high temperatures in the upper 70s to lower 80s, though if cloud 
cover is more persistent than anticipated it will be a little cooler 
than that.

Most models indicate drying by tonight, although some of the CAMs 
and the NAM would leave a threat of isolated convection lingering 
even into part of the overnight period. At this point, kept the 
forecast dry with forcing drifting away, but it may be something 
that will have to be updated in future forecasts. Lows tonight will 
again be in the 60s.

.LONG TERM...(Sunday through Friday)
Issued at 407 AM CDT Sat Aug 3 2019

Sunday looks to be a better day as upper level ridging in the 
western CONUS nudges a bit eastward. With a southeasterly low level 
flow taking on a more south/southwesterly direction, temperatures 
should warm into the mid and upper 80s.

The quiet weather will be short-lived however, as a cold front 
dropping through the region will bring a return of thunderstorm 
chances on Monday. Depending on the timing of the frontal passage, 
convective parameters would support the threat for a few severe 
storms on Monday afternoon and evening.

The remainder of next week looks to have temperatures at or just 
below normal in a northwesterly upper level flow across the region. 
Hard to pin down timing for convective chances, with no significant 
systems expected, though there could be a periodic low chance of 
thunderstorms through the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1139 AM CDT Sat Aug 3 2019

Morning rain has diminished although isolated to scattered showers
will likely continue into the evening hours. At this time, the
better chances for this activity look to be west of KFSD/KSUX and
south of KHON although can't rule out some of this precipitation
making its way into the terminals at times. MVFR ceilings will 
also continue for areas west of I-29 into the afternoon.

Some uncertainty exists overnight with how much lingering
precipitation will be around. This will be important as a moist
boundary layer and lighter winds could lead to some lower
ceilings or fog potential late tonight into early Sunday if
enough clearing develops, with areas near/west of the James River
the highest threat area. Will leave mention minimal at this time 
given uncertainty. 

&&

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

$$

SHORT TERM...JM
LONG TERM...JM
AVIATION...Kalin