Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 232340
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
540 PM MDT SAT APR 23 2016

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 225 PM MDT SAT APR 23 2016

UPPER LEVEL ANALYSIS SHOWS LOW SPINNING OVER NORTHERN UTAH...PUSHING
CIRRUS INTO THE NORTHERN PLAINS WHERE A WEAK RIDGE RESIDES. RADAR
IS NOT PICKING UP ON ANY SHOWERS ACROSS THE CWA ATTM...ALTHOUGH
SATELLITE DEPICTS SOME CUMULUS POPPING UP OVER THE ROCKIES. AT THE
SURFACE...LOW PRESSURE IS OVER NORTHEASTERN WY...WITH WARM FRONT
STRETCHED ACROSS NORTHWEST/CENTRAL SD. WINDS ARE BREEZY FROM
VARYING DIRECTIONS...AND TEMPS ARE RISING INTO THE 70S AND LOWER
80S.

AS UPPER LOW MOVES OVER WY LATE THIS AFTERNOON AND EVENING...SHOWERS
AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AND MOVE INTO THE CWA. NAM
IS STILL SHOWING HIGHER MLCAPE VALUES OF 2-3 KJ/KG AS COMPARED TO
THE ECM/GFS VALUES AROUND 1-1.5 KJ/KG BY 00Z ACROSS MUCH OF WESTERN
SD. WITH 0-6KM SHEAR AROUND 30 KTS...THERE IS A MARGINAL RISK OF
SOME STRONG TO SEVERE THUNDERSTORMS. HOWEVER...MOISTURE IS LIMITED
AND BY THE TIME BETTER MOISTURE MOVES INTO THE REGION
OVERNIGHT...INSTABILITY WILL HAVE DIMINISHED. LOWS WILL BE MAINLY IN
THE 40S...WITH SOME 50S ACROSS CENTRAL SD. WITH 30S IN THE BLACK
HILLS...MAY BE SOME LIGHT SNOW THERE OVERNIGHT.

ON SUNDAY...700MB LOW MOVES INTO WESTERN SD...AND PRECIP AND COOLER
AIR WILL WRAP AROUND INTO NORTHWESTERN SD AND NORTHEASTERN WY.
COOLING AFTERNOON TEMPERATURES ACROSS NORTHEASTERN WY AND THE BLACK
HILLS MAY RESULT IN SOME SNOWFALL...WITH MINIMAL ACCUMULATIONS AS
SOME MELTING IS EXPECTED. WEAK INSTABILITY MAY ALLOW FOR A FEW
THUNDERSTORMS TO DEVELOP ACROSS THE SD PLAINS. MEANWHILE...A DRY
SLOT WILL FORM OVER SOUTH CENTRAL SD AT LEAST THROUGH THE MORNING.
PRECIP WILL SHIFT EASTWARD WITH THE LOW DURING THE AFTERNOON AND
OVERNIGHT. BEHIND THE SURFACE LOW...NORTHWESTERLY WINDS WILL BECOME
BREEZY. WITH CLOUDS/RAIN/SNOW ACROSS THE NORTHWESTERN THIRD OF THE
CWA...AND SUNNY SKIES WITH SOUTHWEST WINDS ACROSS SOUTH CENTRAL
SD...A WIDE RANGE OF HIGHS ARE FORECAST FOR SUNDAY...AND MODELS ARE
HAVING SOME DIFFICULTY. CURRENTLY EXPECTING LOWER 40S ACROSS
NORTHEASTERN WY AND THE BLACK HILLS...TO MID 70S ACROSS SOUTH
CENTRAL SD. LOWS WILL DIP INTO THE 30S ACROSS MUCH OF THE CWA
OVERNIGHT...WITH RAIN MIXING WITH OR CHANGING TO SNOW...BUT STILL
WITH MINIMAL ACCUMULATIONS. OVERALL BY THE END OF THE
WEEKEND...AROUND AN INCH OF QPF IS EXPECTED ACROSS NORTHWESTERN SD
INTO THE NORTHERN HILLS AND NORTHEASTERN WY...DECREASING SOUTH AND
EASTWARD WITH A RATHER SHARP CUTOFF TO ONLY A TENTH OF AN INCH OR SO
ACROSS SOUTH CENTRAL SD. DEPENDING ON WHERE THE DRY SLOT SETS
UP...MORE OR LESS PRECIP THAN FORECAST MAY FALL ACROSS THE AREA.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 225 PM MDT SAT APR 23 2016

FAIRLY PROGRESSIVE MOIST SW FLOW EXPECTED INTO NEXT WEEKEND WITH
A SERIES OF UPPER LOWS PUSHING THROUGH THE REGION. WHILE WDSPRD
RAIN CAN BE EXPECTED FOR MUCH OF NEXT WEEK...EACH LOW WILL SHIFT A
LITTLE FURTHER SOUTH AS IT CROSSES INTO THE PLAINS AND WILL BRING
PROGRESSIVELY COOLER TEMPS THROUGH AT LEAST THE MIDDLE OF NEXT
WEEK. THIS COULD BRING LOWERING SNOW LEVELS IN THE TERRAIN OF NERN
WY AND THE BLKHLS...AND POSSIBLY ONTO THE PLAINS AT TIMES IN WRN
SD. CERTAINLY NEEDS TO BE MONITORED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 539 PM MDT SAT APR 23 2016

A FEW THUNDERSTORMS ARE POSSIBLE THIS EVENING ACROSS NORTHEAST
WYOMING INTO FAR WESTERN SOUTH DAKOTA...WITH INCREASING COVERAGE
OF SHRA/TS OVERNIGHT. MVFR/LCL IFR CONDITIONS WITH THE
THUNDERSTORMS. MVFR CIGS WILL SHIFT SE INTO THE AREA SUNDAY
MORNING BEHIND A COLD FRONT.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...JOHNSON
AVIATION...77



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