Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 191712
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1112 AM MDT Sat Oct 19 2019

.DISCUSSION...(Today Through Friday)
Issued at 252 AM MDT Sat Oct 19 2019

Current surface analysis shows cold front well south and east of
the region, with high pressure over the Rockies. Upper level
analysis shows weak shortwave trough passing mostly to the north
of the area, with fast zonal flow westward to a stronger trough
off the Pacific NW coast. Skies are mostly clear with temps in the
30s and lower 40s. Winds have diminished overnight, mostly light
from the west to northwest.

The first half of the weekend will be seasonably nice, with clear to
partly cloudy skies and highs today in the mid 50s to mid 60s, 50s
over the Black Hills. Clouds will increase from the west late today
and this evening as trough over the Pacific NW moves quickly across
the Rockies tonight. A cold front and area of low pressure at the
surface will move quickly east-southeast across the northern
Rockies, arriving in our area later tonight and Sunday morning.
Chances for pcpn will increase from west to east overnight and
Sunday morning. Medium range models still not in real good agreement
on how the trough evolves as it moves into the Plains on Sunday. GFS
and NAM are strongest and furthest north with the system, bringing
some areas of heavier pcpn to the forecast area, while EC and
Canadian are weaker and faster, bringing mostly lighter pcpn to most
of the area before the system winds up further east across the upper
midwest. Temps still look warm enough over many areas for mainly
rainfall. However, temps will become cold enough over the Black
Hills and much of northeast WY for snowfall, with several inches
possible over the favored higher elevation upslope areas of the
northern Black Hills as north-northwest winds increase. Strong winds
can be expected across a good portion of the forecast area Sunday
into Sunday night as low pressure intensifies to the east of the
region. The strongest winds look to be in the Rapid City area and
especially the adjacent plains to the east, where gusts to 60 mph
look possible. Will issue a high wind watch for the Pennington
County plains and southern Meade County plains.

The first part of next week looks relatively quiet with near or
slightly below average temps, though breezy as northwesterly flow
aloft persists. The next system during midweek looks to be
relatively weak at this point with some light rain and snow
possible, but it will bring colder air into the region for the
latter part of the week.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1105 AM MDT Sat Oct 19 2019

VFR conditions will continue until around 09Z on Sunday morning.
After 09Z, areas of IFR conditions will develop due to rain and
snow over northeastern Wyoming, the Black Hills and far western
South Dakota. Wind gusts of 35-40kts will develop around 12Z on
Sunday morning.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Watch from Sunday afternoon through Sunday evening for
     SDZ031-073.

WY...None.
&&

$$

DISCUSSION...26
AVIATION...10


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