Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 181124

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
524 AM MDT Wed Jul 18 2018

.DISCUSSION...(Today Through Tuesday)
Issued at 254 AM MDT Wed Jul 18 2018

The upper disturbance associated with the precipitation currently
occurring over parts of western and central SD will shift
eastward this morning as another shortwave trough drops into the
region from the northwest and slowly crosses the forecast area
today. Abundant low level moisture and diurnal heating is expected
to push SBCAPE to around 2500J/KG over parts of south central SD
this afternoon with a narrow band of enhanced CAPE extending
northward along the eastern slopes of the Black Hills into far NE
WY/SE MT. Dryer air is expected over much of northeastern Wyoming
as subsidence develops to the west of the shortwave trough
crossing the area. The combination of surface based instability,
some weak CAA and cyclonic flow aloft is expected to develop some
showers and thunderstorms today with shear profiles indicating the
strongest storms expected over parts of south central SD this
afternoon. May also see a few stronger storms develop over the
Black Hills. Any showers and thunderstorms should end during the
evening as large scale subsidence overspreads the region.

Mainly dry weather with seasonable temperatures is then expected
from Thursday into Saturday with another chance of showers and
thunderstorms late Saturday aftn into Saturday night as a
shortwave trough crosses the northern plains. Slight cooler
temperatures are expected on Monday and Tuesday with low chances
for showers or thunderstorms.


.AVIATION...(For the 12Z TAFS Through 12Z Thursday Morning)
Issued At 521 AM MDT Wed Jul 18 2018

TSRA with MVFR/local IFR conditions are expected again across the
SD plains late this morning through the afternoon. Strong storms
will be possible. Additionally, heavy rainfall will be possible
with any storms. VFR conditions are expected across northeast WY
into the Black Hills area, and by this evening across the SD




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