Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 140408

Area Forecast Discussion
National Weather Service Sioux Falls SD
1108 PM CDT Sun May 13 2018

.SHORT TERM...(This evening through Monday)
Issued at 305 PM CDT Sun May 13 2018

The short term forecast continues to feature widespread cloudiness
and chances for showers with a few rumbles of thunder. Best chances
for showers and storms remain to our south closer to the surface
boundary but a few could still sneak into our southern and
southeastern zones, where there is enough elevated instability for
perhaps a marginally severe storm if there happens to be a storm.
Without much in the way of a pressure gradient to speak of, winds
will continue to be light. As winds go nearly calm over northwest
Iowa overnight, could get some patchy fog in that area thanks to
moisture from recent rainfall. With a repeat of last night on tap in
terms of cloud cover and wind, have held lows above consensus.

Winds will become northerly Monday, with clouds beginning to
decrease in coverage by sunset. Still, held highs just below
consensus as significant clearing will likely wait until Monday
night. While the best chances once again remain to our south and
southwest, yet another shortwave will drive a slight chance for
showers and storms across much of the CWA Monday afternoon and
evening. Progged thermodynamic profiles reveal enough elevated CAPE
for thunder but overall instability profiles are skinny, so am not
expecting severe weather, even south along Highway 20.

.LONG TERM...(Monday night through Sunday)
Issued at 305 PM CDT Sun May 13 2018

Upper low stuck over the western CONUS will begin to break down by
the middle of the week, with subtle mid level ridging expected by
Wednesday. The result will be a welcome respite from the cloudy
conditions and rain chances and high temperatures likely in the 80s.

Upper level flow becomes quite slow over the central United States
by the end of the week with divergent model solutions bringing
various shortwaves across the region. Multiple periods of chance
PoPs are warranted. More potent upper level wave looks to drive a
frontal passage Friday night into Saturday, bringing the highest
chances for showers and storms of the extended forecast with it.
This frontal passage has trended slower in recent model runs, so
timing is still too uncertain to advertise a specific period with
likely PoPs unfortunately.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1104 PM CDT Sun May 13 2018

Chaotic areas of MVFR ceilings remain at late evening across
southeast SD and into northwest IA, with VFR ceilings most other
locations. Trend in ceilings should be down into the MVFR and
some IFR conditions for most locations overnight with high degree
of low level moisture, and approach of convection toward the lower
Missouri River valley later tonight. Even with some breaks in MVFR
conditions, should get redevelopment of convective clouds heading
into the afternoon hours which will be marginally MVFR to VFR in
height, and should have a scattering of showers and thunderstorms
for KFSD/KSUX areas as weak mid-level wave moves across during the




SHORT TERM...Ferguson
LONG TERM...Ferguson
AVIATION...Chapman is the U.S. government's official web portal to all federal, state and local government web resources and services.