Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 191714

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1114 AM MDT Sun Mar 19 2017

.SHORT TERM...(Today Through Monday Night)
Issued at 202 AM MDT Sun Mar 19 2017

Main upper trough will continue to shift east across southern
Canada, supporting a weak cold front south into the FA today, in
a stalling fashion. Northern areas will see cooler temps, while
southern areas will see highs in the upper 70s. CAA has trended
weaker with this system today, supporting slightly warmer temps
most areas than previous forecasts. Weak FGEN across the far NW
may support a shower there this morning, with diurnal heating
possibly supporting a few shra/sprinkles over the northern Black
Hills this afternoon. Very dry sub-cloud layer will highly limit
shra chances. Slightly better chances for shra are on track for
the northern third tonight as a secondary impulse advects through
the region, best chances over far NW SD. This impulse will re-
invigorated CAA and help shift the frontal boundary further south
Monday, supporting much cooler weather across the FA. A stronger
upper trough will affect the region Monday night, with rain and
snow likely over most of the area. Some light accums will be
possible as enough cold air will be in place. Current progs
suggest 1-2 inches possible. However warm near sfc layer will
fight accums on other than grassy sfc`s.

.LONG TERM...(Tuesday Through Saturday)
Issued at 202 AM MDT Sun Mar 19 2017

Progressive amplifying flow can be expected the remainder of the
week, supporting unsettled conds. Long wave trough will affect the
region Thur-Fri with another system next Sunday. Still many
details to be worked out with these systems, namely track, trough
fracturing, and CAA/thermal fields. Near seasonal to slightly
above seasonal temps expected mid week on, with breezy conds.


.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 1112 AM MDT Sun Mar 19 2017

VFR conditions will continue through tonight. A cold front will
settle into the area this afternoon with winds veering through
the period. There is a slight chance of high based showers over
northeastern Wyoming, the Black Hills and northwestern South
Dakota this afternoon, spreading a bit further south tonight. An
additional wave may bring a few more showers Monday morning with
local MVFR conditions.


Issued At 202 AM MDT Sun Mar 19 2017

Warm dry westerly flow will support near critical fire weather
conditions this afternoon from southern Campbell county WY to Fall
River county SD. RH is expected to drop to 15-20 percent there.
Winds will become sustained at 15 to 25 mph, with higher gusts
possible. Given narrow window for critical fire weather conds and
a settling cold front, have held off on any headlines. Extreme
grassland will cover concerns in SW SD.




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