Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 242313
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
513 PM MDT SUN APR 24 2016

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 229 PM MDT SUN APR 24 2016

UPPER LEVEL ANALYSIS SHOWS CLOSED LOW OVER SOUTHWESTERN SD. THE
CWA IS STILL BEING DRY-SLOTTED...WITH SHOWERS/STORMS CIRCLING
AROUND IT. AN AREA OF LOW CLOUDS CONTINUES TO COVER NORTHEASTERN
WY AND NORTHWESTERN SD. A LINE OF SHOWERS HAS POPPED UP ALONG A
CONVERGENCE ZONE/BOUNDARY OVER THE CENTRAL/SOUTHERN HILLS...AND
VISIBLE SATELLITE SHOWS CUMULUS DEVELOPING ALONG THIS BOUNDARY
INTO CENTRAL SD WHERE THE SURFACE LOW RESIDES. ANOTHER LINE OF
CUMULUS IS FORMING ON THE NORTHWESTERN SIDE OF THE LOW OVER
ZIEBACH COUNTY. WINDS ARE GENERALLY WESTERLY...AND TEMPS RANGE
FROM THE 30S ACROSS NORTHEASTERN WY TO THE MID 70S ACROSS SOUTH
CENTRAL SD.

SHOWERS WILL MOVE INTO THE AREA TONIGHT AS LOW SHIFTS EASTWARD. WEAK
INSTABILITY MAY ALLOW FOR A FEW THUNDERSTORMS ACROSS THE SD PLAINS
LATE THIS AFTERNOON AND EVENING. COLD AIR ADVECTION AND WET-BULB
EFFECTS MAY RESULT IN PRECIP FALLING AS SNOW ACROSS NORTHEASTERN
WY...NORTHWESTERN SD...AND THE BLACK HILLS TONIGHT AND INTO MONDAY
MORNING. MINIMAL ACCUMULATIONS ARE EXPECTED. LOWS TONIGHT WILL RANGE
FROM THE 30S ACROSS THE WESTERN 2/3 OF THE CWA TO THE 40S FARTHER
EAST.

LOW PRESSURE SYSTEM WILL WEAKEN INTO AN OPEN SHORTWAVE AS IT MOVES
INTO MN ON MONDAY. CHANCES FOR PRECIP WILL CONTINUE ACROSS THE
NORTHERN HALF OF THE CWA...BUT BEST UPPER ENERGY AND MID-LEVEL
MOISTURE WILL BE OVER ND. BRIEF RIDGING BETWEEN SYSTEMS WILL BRING
DRIER WEATHER TO THE SOUTHERN HALF. HIGHS MONDAY WILL RANGE FROM THE
40S ACROSS NORTHWESTERN SD...TO NEAR 60 ACROSS SOUTHWESTERN SD.

NEXT UPPER LOW MOVES OVER THE CENTRAL ROCKIES MONDAY NIGHT...WITH
RAIN/SNOW EXPANDING ACROSS NORTHEASTERN WY AND SOUTHWESTERN SD
OVERNIGHT. BY TUESDAY MORNING...SREF/ECMWF/GFS ARE SHOWING 1-4
INCHES OF SNOW ACROSS NORTHEASTERN WY AND THE BLACK HILLS...WHILE
THE NAM HAS UP TO A FOOT OF SNOW FOR THOSE AREAS. CURRENTLY HAVE UP
TO 2 INCHES IN THE FORECAST...AS MELTING WILL REDUCE
ACCUMULATION...BUT MAY NEED TO CONSIDER HIGHER AMOUNTS. LOWS WILL BE
IN THE 30S.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 229 PM MDT SUN APR 24 2016

VERY WET WEATHER WILL SET UP FOR THE DURATION OF THE LONG TERM
WITH SEMI-PROGRESSIVE SW FLOW EXPECTED. STRONG UPPER LOW WILL
EJECT SLOWLY ACRS NEB ON TUE-WED WITH INVERTED TROF EXTENDING NW
THROUGH WY/MT. SHOULD BE ENOUGH COLD AIR WORKING INTO THE SYSTEM
FOR SOME SNOW...ESPECIALLY TUESDAY NIGHT IN THE HIGHER TERRAIN OF
WY/BLKHLS AND POSSIBLY ONTO THE PLAINS OF SD. PCPN CHANCES WILL
DECREASE BUT ONLY SLIGHTLY FOR THU-FRI...WITH NEXT UPPER LOW
PROGGED TO EJECT THROUGH CO INTO NEB FOR THE WEEKEND. COULD BE
SOME RATHER LARGE PCPN TOTALS OVER THE DURATION OF THE
EXTENDED...AND TEMPS EXPECTED TO REMAIN QUITE COOL.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 512 PM MDT SUN APR 24 2016

WDSPRD MVFR/IFR CONDITIONS WILL CONTINUE ACRS NERN WY
AND NWRN SD THROUGH THE PERIOD...WITH THESE CONDITIONS SPREADING EWD
THROUGH THE REST OF WRN SD TONIGHT. SCT SHRA/TSRA WILL CONTINUE
THORUGH THIS EVENING...WITH BEST CHANCE ACROSS SOUTHWEST AND SOUTH
CENTRAL SOUTH DAKOTA.

&&

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

$$

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



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