000
FXUS63 KUNR 170851
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
251 AM MDT THU JUL 17 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 250 AM MDT THU JUL 17 2014

CURRENT SURFACE MAP SHOWS HIGH PRESSURE ACROSS THE CENTRAL
CONUS...WITH WEAK TROF ACROSS THE NORTHERN ROCKIES. FOR
TODAY...SHORTWAVE RIDGE BUILDS ACROSS THE NORTHERN PLAINS.
FORECAST SOUNDINGS BACKING OFF ON THUNDERSTORM POTENTIAL FOR BLACK
HILLS THIS AFTERNOON...WITH MLCAPE LESS THAN 250J/KG AND MLCIN
50-100J/KG. WITH LARGE SCALE SUBSIDENCE ACROSS THE AREA...WILL
REMOVE MENTION OF THUNDERSTORMS FOR BLACK HILLS.

STRONG SHORTWAVE TROF MOVES THROUGH SOUTHERN SASKATCHEWAN ON
FRIDAY...WITH WEAKER TROF ACROSS THE DAKOTAS. SURFACE TROF SLIDES
THROUGH WESTERN SOUTH DAKOTA. DEEP MIXING WEST OF THE TROF WILL
RESULT IN WARM TEMPERATURES AND LOW RELATIVE HUMIDITY. POTENTIAL
EXISTS FOR MIXING TO ERODE CAP...ALLOWING ISOLATED THUNDERSTORMS
TO DEVELOP IN VICINITY OF SURFACE TROF.

&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 250 AM MDT THU JUL 17 2014

A WEAK BOUNDARY WILL WASH OUT OVER WESTERN SD ON SATURDAY AS SOME
SHORTWAVE ENERGY ALOFT IS PROGGED TO PASS OVER THE AREA. THIS COULD
BE ENOUGH TO TRIGGER A FEW THUNDERSTORMS OVER WESTERN SD...
ESPECIALLY THE BLACK HILLS...IN THE AFTERNOON. THERE WILL BE ENOUGH
INSTABILITY AROUND FOR STRONG STORMS IF THEY DO DEVELOP. HOT AIR
WILL BE IN PLACE OVER THE REGION...WITH HIGHS MOSTLY IN THE 90S ON
THE PLAINS...80S OVER THE BLACK HILLS.

HIGH PRESSURE ALOFT OVER THE FOUR CORNERS REGION WILL KEEP THE
MAINLY DRY AND HOT PATTERN GOING THROUGH THE EXTENDED PERIOD AS MID
LEVELS CONTINUE TO WARM. HOWEVER...WILL NOT RULE OUT ISOLATED LATE
DAY THUNDERSTORMS EARLY NEXT WEEK...ESPECIALLY OVER THE BLACK HILLS
AND NORTHERN PORTIONS OF THE CWA...AS WEAK UPPER LEVEL DISTURBANCES
AND SOME MONSOONAL MOISTURE ROTATE AROUND THE HIGH. HIGHS WILL
CONTINUE TO BE IN THE 90S ON THE PLAINS...80S IN THE BLACK HILLS.
SOME AREAS EAST OF THE BLACK HILLS WILL LIKELY SEE HIGHS AROUND 100
DEGREES EACH DAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 250 AM MDT THU JUL 17 2014

PATCHY MVFR/IFR CIGS ARE POSSIBLE ACROSS FAR SOUTHWEST SD AND
SOUTHERN PORTIONS OF NORTHEAST WY EARLY THIS MORNING.
OTHERWISE...VFR CONDITIONS CAN BE EXPECTED THROUGH THE PERIOD WITH
SOUTH TO SOUTHWEST WINDS.

&&

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

$$

SHORT TERM...7
LONG TERM...26
AVIATION...26