Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 101717

Area Forecast Discussion
National Weather Service Sioux Falls SD
1217 PM CDT Thu Aug 10 2017

.SHORT TERM...(Today and Tonight)
Issued at 301 AM CDT Thu Aug 10 2017

Cold front continues to pivot through the area tonight. This front
is being driven southward by a well developed upper trough over the
eastern Dakotas. Further south, lingering mid-level banded moisture
will produce clouds along or south of the Missouri river into mid-
morning.  Fairly quiet conditions are likely across the forecast
area in the short term, but will need to watch a couple items.

Clouds will begin to pivot southward through the day today, and it`s
possible that we`ll see instability showers develop, by mid-day. For
now, will advertise as sprinkles, but it`s possible PoPs may need to
be increased, especially in the northern portions of the CWA.
Temperatures will remain below normal today.

Clouds will take their time clearing tonight, and that may lead to a
slowly than normal diurnal curve. With light winds and clearing
skies, low 50s seem attainable.

.LONG TERM...(Friday through Wednesday)
Issued at 301 AM CDT Thu Aug 10 2017

Relatively quiet weather prevails through Friday night as surface
high pressure located over central Dakotas builds over the region.
Light east to northeast surface winds will maintain the region dry
with unseasonably temperatures.

Unsettled weather returns this weekend and looks to persist through
Monday. A strong upper trough currently located over the
International Border and Northern Plains will make its way southward
into the High Plains. While the main trough slowly moves east-
southeast, several impulses of energy embedded within the flow aloft
will begin to bring spotty showers and storms starting Friday night.
Decent forcing will be in place thanks to the upper-level jet, and
strong isentropic lifting on the 305K layer. Model soundings also
suggest deep saturation, mostly over southeast South Dakota and
southwest Minnesota through Sunday morning. That said, off and on
showers and storm chances are expected to increase Friday night west
of the James River, and then spread eastward through Sunday. Better
precipitation chances look to fall Saturday night.  At this time,
the instability and deep layer shear are weak, therefore severe
weather threat is low. In terms of temperatures, well below normal
highs are expected on Saturday with temperatures in the lower to mid
70s. Sunday looks warmer, but still cooler than normal.

Upper-level flow pattern changes next week with a weak upper ridge
building over the region from the Pacific Northwest. Some models
prog several weak disturbances over the area bringing
skittish/spotty chances of precipitation each day. With that said,
left only low precipitation chances for the second half of the


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1216 PM CDT Thu Aug 10 2017

ceilings will gradually lift to VFR with continued daytime
heating. Isolated showers will be possible over east central SD
into southwest MN this afternoon. VFR conditions are expected
tonight into Friday.




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