Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 181714

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1114 AM MDT Tue Oct 18 2016

.SHORT TERM...(Today Through Wednesday Night)
Issued at 243 AM MDT Tue Oct 18 2016

Upper flow is nearly zonal over the western and central CONUS,
with next decent wave to affect the CWA over the Pacific
Northwest. Showers have moved out of the CWA, and skies are
becoming mostly clear. Winds are northwesterly around 10 kts, and
temps at 2AM are in the 40s.

A generally dry day is expected. There may be a few afternoon
showers over the Hills, and a tiny bit of CAPE suggests thunder may
be possible again. A surface low over ND will produce some breezy
winds over northwestern SD, but nothing remarkable. Highs will be
in the 60s, which is near average for mid-October.

Chances for precip will increase tonight as upper wave approaches
the northern plains. Snow will be possible over the Black Hills,
with a rain/snow mix over chilly northeastern WY, and rain farther
east. No snow accumulations are expected tonight. A cold front will
begin pushing south into SD, and lows will be in the 30s to lower
40s, warmer across south central SD.

Precip will expand across much of the CWA Wednesday, along an area
of enhanced frontogenesis/lift that gradually moves from
northeastern WY to south central SD. Some hi-res models hint at the
possibility of afternoon thunderstorms again, supported by some very
weak CAPE. Under a cooler airmass following the cold front, highs
will be only in the 40s and 50s. As temperatures cool into the 30s
overnight, precipitation will change to snow in some places.
ECMWF/GFS/NAM/SREF in AWIPS all showing snow accumulations possible.
However, for the most part, models in BUFKIT show mostly rain.
Forecasting about an inch of snow in the Hills, where temps for
evening precip will be cold enough. After midnight, predicting just
a small area of precip over warmer south central SD, most of which
should be rain with minimal snow accumulations.

.LONG TERM...(Thursday Through Monday)
Issued at 243 AM MDT Tue Oct 18 2016

Confidence is high with a fairly staunch upper level ridge over
the Rockies into the northern Plains Thursday through Monday.
Temperatures will be 3-8F above normal on average with dry weather
expected. A dry cool front will move through Saturday night, but
temperatures will only drop a few degrees for Sunday. A slightly
more active weather pattern may develop for the middle of next


.AVIATION...(For the 18Z TAFS Through 18Z Wednesday)
Issued At 1112 AM MDT Tue Oct 18 2016

An isolated shower or thunderstorm is possible late this afternoon
over the Black Hills. Rain or snow showers are possible later tonight
across parts of northeastern Wyoming and southwestern South Dakota
where local MVFR ceilings are possible. Otherwise, VFR conditions
will prevail through the period.




SHORT TERM...Pojorlie
LONG TERM...Helgeson
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