Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 261729
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1229 PM CDT Sat May 26 2018

.SHORT TERM...(Today and Tonight)
Issued at 341 AM CDT Sat May 26 2018

Welcome to Summer! Temperatures today will once again be more
typical of mid-late summer than late May, with readings expected to
reach the 90s across the region under abundant sunshine. Hints in
some of the high-res guidance of isolated storms developing late
afternoon/early evening along a weak convergence boundary in south
central South Dakota, but air mass is quite dry with subsidence as
the upper ridge builds northward into the Dakotas, so will keep the
forecast dry for now.

As low level jet increases across the High Plains tonight, could see
a few elevated storms develop in area of increasing warm advection.
However this remains focused to our northwest/north, so expect any
convection will likewise remain north of our forecast area tonight.
Temperatures remain mild, with lows in the mid 60s most areas.

.LONG TERM...(Sunday through Friday)
Issued at 341 AM CDT Sat May 26 2018

Sunday looks to be hot as the ridge hangs on for another day.
Upper trough over the Rocky Mountains will begin to break down by
Sunday, driving lee pressure falls to our west. A decent pressure
gradient will set up across the region, driving southerly winds,
which could get breezy west of the James River. The end result
will be the warmest day in some time across the region with highs
in the mid to upper 90s. Have leaned just above consensus guidance
which has been underdoing temperatures so far in our early season
heat wave.

As the aforementioned western trough continues to break down and
translate eastward through Monday and Tuesday, our warm temperatures
aloft will help us stay mostly dry until Monday night as we remain
capped off Monday afternoon. Eventually though, the combined effect
of several shortwaves cooling the mid levels will lead to showers
and thunderstorms. The most active periods appear to be late Monday
night/Tuesday morning via a shortwave and Tuesday evening as the
main wave swings through the upper Midwest. Too early to make
pronouncements about severe potential, but there will at least be
a good amount of potential instability to work with.

The remainder of the extended features a mid week respite from the
heat until ridging once again builds in by Friday. Guidance shows
occasional mid level disturbances impacting the region, so have kept
in small chances for showers and storms in a few periods. Not enough
agreement to go with higher chances at this time.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1226 PM CDT Sat May 26 2018

Clear skies, light winds, and above normal warmth is expected over
the next 24 hours. Due to the summer-like heat, density altitudes
will be higher than usual for this time of year.

&&

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

$$

SHORT TERM...JH
LONG TERM...Ferguson
AVIATION...VandenBoogart


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