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068
FXUS63 KUNR 162330
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
530 PM MDT Wed Aug 16 2017

.DISCUSSION...This Evening Through Wednesday
Issued at 255 PM MDT Wed Aug 16 2017

Current surface analysis shows low pressure now over western IA,
with showers exiting south central SD. Upper level analysis shows
upper trough from eastern SD to western KS. Skies range from clear
across much of northeast WY to cloudy over south central SD.
Temps range from the upper 60s over south central SD to the upper
70s across parts of northeast WY and northwest SD. Winds are
mostly north to northwest at 10 to 20 mph across the plains.

A warmer and drier airmass will move over the area for the rest of
the week and most of the weekend as near zonal flow develops over
the region. The best chance for showers and storms through this
period will be Thursday afternoon and evening as a shortwave and
surface trough quickly cross the area. With drier airmass across the
area, instability will be relatively weak, with the threat for
severe storms looking to be minimal. However, some gusty winds will
be possible with any stronger storms. Temperatures over the next few
days will be near to above average after temperatures mostly below
average for the last 2+ weeks.

A more active flow is likely to return by the end of the weekend and
early next week. Chances for showers and thunderstorms are forecast
to increase late Sunday and continue into Sunday night as a
shortwave disturbance crosses the area. Another disturbance with
more showers and thunderstorms is progged right now for Monday
afternoon and evening, with some cloud cover possible across at
least parts of the area Monday morning/midday. Model differences are
fairly large at this point, so level of certainty is rather low.

A ridge is expected to build over the Rockies during the middle part
of next week, with at least some slight chances for showers and
storms. Temperatures look to be near average levels for early to mid
week.

&&

.AVIATION...For the 00Z TAFS Through 00Z Thursday Evening
Issued At 524 PM MDT Wed Aug 16 2017

MVFR clouds over south central SD will decrease this evening, with
mostly clr skies across the area overnight. VFR sct-bkn clouds
with sct tstms will develop Thursday as a trof crosses the area.
Northwest winds across the western SD plains will decrease early
this evening, becoming southeast Thursday morning while winds will
switch to the northwest over northeastern WY.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WY...None.
&&

$$

DISCUSSION...26
AVIATION...55