Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 180934
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
334 AM MDT MON JUL 18 2016

.SHORT TERM...(Today Through Tuesday Night)
Issued at 310 AM MDT Mon Jul 18 2016

Water vapor shows upper ridge amplifying into the nrn
rockies. Short wave trof ahead of the ridge is moving through the
nrn plains with isold convection ongoing from just east of the
Blkhls into scntrl SD. Most of this activity should move out of
the cwfa early this mrng.

Today...Upper ridge shifts ewd into the nrn plains with thermal
profiles suggesting temps will rise into the 90s across much of
the cwfa. Short wave moving into the ridge later in the day will
result in sct convection developing from nern WY through the
Blkhls into swrn SD...with activity spreading ewd this evening
generally south of I-90 in wrn SD. Modest deep layer shear
suggests a few stronger to svr storms with large hail and damaging
wind gusts the main threats.

Tuesday...Thermal ridge builds ewd into the cwfa with temps
pushing well into the 90s to lower 100s. Dewpoints in cntrl SD may
be high enough where a heat advisory may be needed that area.
Forcing limited with only a slight chance of tstms in the Blkhls.

.LONG TERM...(Wednesday Through Sunday)
Issued at 310 AM MDT Mon Jul 18 2016

Upper level ridge of high pressure will be well established
across the central CONUS by mid-week, with very hot and mainly dry
conditions expected. Medium range guidance has 850mb temps
climbing above 30C over the CWA for Wednesday and Thursday. Many
locations across the plains will likely see triple digit heat both
days. The upper ridge breaks down slightly by the weekend as a
weak impulse crosses the northern Rockies. This may bring a slight
chance of afternoon and evening showers and thunderstorms to parts
of the forecast area, along with slightly cooler temperatures.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Tuesday Morning)
Issued At 310 AM MDT Mon Jul 18 2016

Isolated showers and thunderstorms will dissipate across south
central SD by early morning. Local MVFR visibility possible with
the precipitation. Low level wind shear expected to persist
through 14Z across northeast Wyoming and far western SD. Scattered
thunderstorms expected again across the area this afternoon and
evening, mainly from the Black Hills into south central South
Dakota.

&&

.FIRE WEATHER...
Issued At 310 AM MDT Mon Jul 18 2016

A dry line will push into far wrn Campbell County late this aftn
and will allow relative humidities to drop to around 15 percent.
Southwest winds could become breezy behind the dry line and may
push conditions to near red flag criteria for a short period of
time. These conditions will be monitored closely.

Temperatures will reach well into the 90s with a few areas around
100 on Tuesday. Very dry air will result in relative humidities
at or below 15 percent across much of nern WY and parts of far wrn
SD...but winds will not be particularly strong. Expect very hot
conditions through the week.

&&

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

$$

SHORT TERM...Johnson
LONG TERM...15
AVIATION...15
FIRE WEATHER...Johnson


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