Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 292046
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
246 PM MDT SUN MAY 29 2016

.SHORT TERM...(This Evening Through Monday Night)
Issued at 225 PM MDT Sun May 29 2016

20Z sfc analysis shows high pressure over the eastern two-thirds
of the dakotas and nebraska with weak low pressure to the east of
the Rockies. Upper analysis shows a few wiggles in mainly zonal
flow aloft over the northern plains.

Diurnal heating and sfc dewpoints ranging from 40-50F have
increased the MUCAPE to 500-1500J/KG over parts of northeastern WY
and western SD. Scattered thunderstorms have develop over nwrn SD,
far nern WY and the Black Hills this afternoon. 0-6km bulk shear
is around 15-20m/s indicating that isolated strong to severe
storms are possible during the rest of the aftn and into the early
evening with large hail the main threat. An upper low will drop
southward out of Alberta and into nwrn Montana later tonight
causing a sfc low to develop over south central MT/north central
WY. A low level jet will develop to the east of the sfc low
increasing low and mid level Theta-e advection and thunderstorm
chances mainly over central South Dakota later tonight.

On Monday, the upper low will dip into eastern Montana as it
strengthens. The surface low will also deepen slightly as it
moves from western into central South Dakota. A relatively weak frontal
boundary will connect with the low later in the day with notable
return flow to the east of the boundary. Dew points in the 50s
pool east of the boundary creating 1-2KJ/kg MLCAPE by afternoon.
0-6km bulk shear will increase to 15-20m/s. The wild card is any
ongoing convection from Sunday night and it`s effect on surface
features. If sustained heating occurs ahead of the low, suspect
severe thunderstorms will develop by afternoon and then shift
southeastward Monday evening. Large hail and damaging winds will
be possible. As the surface low pushes east of the forecast area,
models advertise substantial frontal push, pressure rises, and a
short period of gusty northwest winds on monday night.

.LONG TERM...(Tuesday Through Sunday)
Issued at 225 PM MDT Sun May 29 2016

As the upper low passes through the Dakotas, chances
for showers/storms continue on Tuesday, mainly across northwestern
SD, the Black Hills, and portions of northeastern WY. Cooler
temperatures in the 60s, along with breezy northwest winds, are
expected for Tuesday into Wednesday. Other than some isolated
showers/storms over the Hills, the second half of the week looks
dry.  A warming trend is also expected, with temperatures climbing
into the 80s by Friday.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 225 PM MDT Sun May 29 2016

Scattered showers and thunderstorms will redevelop this
afternoon and early evening, then diminish after sunset. Local MVFR
conditions will be possible with the precipitation.

&&

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

$$

SHORT TERM...10
LONG TERM...13
AVIATION...13



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