Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 191704
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1104 AM MDT FRI AUG 19 2016

.SHORT TERM...(Today Through Saturday Night)
Issued at 140 AM MDT Fri Aug 19 2016

Upper level analysis shows a broad trough over much of the
northern CONUS, with the next wave to affect the northern plains
currently over MT. The CWA is mostly dry between the first round
of precip and the next one moving in from the northwest. Winds are
light and variable, and temperatures are falling into the 50s.

The next upper wave will pass over the region today, bringing
another round of showers/storms, breezy northwest winds, and cooler
air. A band of heavier precip associated with the boundary will
slowly cross the CWA this morning and afternoon, pushing into
eastern SD this evening. Models show very little CAPE, and so
precipitation will be mainly showers with some isolated
thunderstorms. ECMWF and GFS have generally another tenth to half
an inch today, while the NAM has more than an inch predicted for
northwestern into central SD. Highs will be well below average,
ranging from the lower 60s across northwestern SD and northeastern
WY to the lower 70s across south central SD. Temperatures might
not even reach 60 this afternoon over parts of the Black Hills.
Lows will be mainly in the 40s, with some 30s over the Black
Hills.

High pressure will move into the region behind this system. Dry
weather and a warming trend will begin on Saturday, with highs in
the lower 70s. Northwest winds may be a bit breezy again on the
plains. Some mid-level moisture passing through northwest flow will
bring mostly cloudy skies to much of the western SD plains; however,
profiles are dry at low levels and so no precipitation is expected.
Lows Saturday night will be generally in the 40s.

.LONG TERM...(Sunday Through Thursday)
Issued at 140 AM MDT Fri Aug 19 2016

Progressive but amplified flow expected in the period.
Deep layer ridging will ensue Sun with waa continuing into Mon. Dry
wx forecast through Monday, although some indication for a weak
impulse in westerly flow Monday afternoon, which could fire a few ts
over ne WY. However, bl moisture will be highly limited. Bl moisture
does begin to increase by tues ahead of another strong northern
stream impulse, possibly supporting a shower or storm over the hills
and in scentral SD along an old sfc trough. Forecast models continue
to indicate a stronger northern stream trough tue night into wed,
which would shift a frontal boundary south of the region in a
stalling fashion. Perturbed westerly flow may then support clusters
of shra/ts invof the boundary late next week...mainly across the
southern third to possibly half. As for temps, a warming trend can
be expected through tues, with cooler temps mid next week on given
the active amplified northern stream. Monday looks to be the warmest
day with highs in the low to mid 90s forecast most areas.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Saturday)
Issued At 1103 AM MDT Fri Aug 19 2016

Large band of precipitation associated with cold front currently
pushing through Western South Dakota and Northeastern Wyoming.
Cigs/Vis have generally been in the MVFR/IFR categories within
this rain band. Gusty northwest winds have also been observed.
Drier air will work its way into western parts of our region late
this afternoon and give way to VFR cigs/vis. Expect VFR conditions
everywhere across CWA by tomorrow morning.

&&

.UNR Watches/Warnings/Advisories...
SD...None.
WY...None.
&&

$$

SHORT TERM...Pojorlie
LONG TERM...JC
AVIATION...McKemy



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