National Weather Service Text Product Display

Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 301158
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
558 AM MDT WED JUL 30 2014

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 204 AM MDT WED JUL 30 2014

UPPER RIDGE OVER THE WESTERN CONUS WILL REMAIN IN PLACE THROUGH
THE PERIOD. A SERIES OF WEAK DISTURBANCES ROTATING AROUND THE
RIDGE WILL INTERACT WITH MID-HIGH LEVEL MOISTURE TO PRODUCE
ISOLATED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME.

HAVE INCLUDED A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS OVER
SOUTH CENTRAL SOUTH DAKOTA DURING THE EARLY MORNING HOURS THIS MORNING
FOR A FEW SHOWERS CURRENTLY WORKING SOUTHWARD OVER CENTRAL SOUTH
DAKOTA. WEAK SYNOPTIC SCALE SUBSIDENCE WILL BE LOCATED OVER THE
FORECAST AREA THROUGH MUCH OF THE DAY TODAY...HOWEVER A WEAK
SHORTWAVE PASSING THROUGH THIS AFTERNOON WILL COMBINE WITH DIURNAL
SURFACE HEATING AND WEAK COOLING ALOFT TO CREATE A SLIGHT CHANCE
OF SHOWERS AND THUNDERSTORMS...MAINLY OVER THE SRN BLACK HILLS AND
THE ADJACENT AREAS OF SOUTHWESTERN SOUTH DAKOTA AND ALSO CLOSER TO
THE WAVE OVER PARTS OF CENTRAL SOUTH DAKOTA. A FEW SHOWERS MAY
LINGER INTO THE EARLY EVENING OVER SOUTH CENTRAL SOUTH DAKOTA.
ANOTHER WEAK SHORTWAVE WILL CREATE A SLIGHT CHANCE OF -TSRA OVER
FAR NORTHWESTERN SOUTH DAKOTA ON THURSDAY MORNING WITH THE CHANCES
SPREADING SOUTHWARD OVER THE REST OF WESTERN AND CENTRAL SOUTH
DAKOTA DURING THE DAY AS DIURNAL HEATING AND SLIGHTLY STRONGER CAA
ALOFT COMBINE TO INCREASE THE INSTABILITY. DRY AIR WILL BE FOUND
OVER NORTHEASTERN WYOMING WITH THE MINIMUM RELATIVE HUMIDITY
EXPECT TO FALL INTO THE 15 TO 20 PERCENT RANGE THERE ON THURSDAY
AFTN.

&&

.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 204 AM MDT WED JUL 30 2014

A PERSISTENT HIGH PRESSURE RIDGE OVER WESTERN NORTH AMERICA IS
FORECAST TO REMAIN IN PLACE THROUGH THE SEVEN DAY FORECAST PERIOD.
GENERALLY DRY WEATHER IS EXPECTED THROUGH THIS WEEKEND...BUT MODELS
ARE INDICATING A GRADUAL BREAKDOWN AND SEVERAL WEAK SHORT WAVES
PUSHING INTO THE NORTHERN PLAINS EARLY NEXT WEEK. THE CHANCE FOR
THUNDERSTORMS INCREASES THIS WEEKEND WITH A BETTER CHANCE DEVELOPING
BY MIDWEEK WHEN A STRONG SHORT WAVE MOVES INTO THE PLAINS.
TEMPERATURES WILL BE NEAR SEASONAL AVERAGES BEFORE COOLING A FEW
DEGREES MIDWEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 556 AM MDT WED JUL 30 2014

VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. ISOLATED -TSRA
MAY DEVELOP THIS AFTERNOON OVER SOUTH CENTRAL SD WITH LOCAL MVFR
CIGS IN THE HEAVIEST SHOWERS.

&&

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

$$

SHORT TERM...10
LONG TERM...CARPENTER
AVIATION...CARPENTER

National Weather Service Weather Forecast Office