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000
FXUS63 KUNR 171120
AFDUNR

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

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
ISSUED AT 258 AM MDT THU APR 17 2014

WATER VAPOR IMAGERY SHOWS CYCLONIC FLOW ACROSS THE CENTRAL THIRD OF
THE CONUS WITH A SERIES OF WEAK EMBEDDED SHORTWAVES CROSSING ERN MT
INTO THE DAKOTAS. SURFACE ANALYSIS SHOWS COLD HIGH PRESSURE OVER
THE NORTHERN PLAINS WITH RETURN FLOW WITH RETURN FLOW SETTING UP
OVER THE CWA INTO ERN MT. KUDX RADAR SHOWS FLURRIES/LIGHT SNOW
CROSSING NW SD INTO NE WY.

BROAD UPPER TROUGH WILL CROSS THE REGION TODAY WITH WRN CONUS
RIDGING MOVING INTO THE AREA LATER TODAY. A SERIES OF WEAK WAVES
WILL CROSS THE AREA CONTINUING SLIGHT CHANCE POPS OVER THE CWA.
PRECIP THAT DOES FALL WILL BE SNOW THIS MORNING...BECOMING RAIN IN
THE AFTERNOON AS TEMPS RISE INTO THE UPPER 40S TO UPPER 50S. DRIER
AIR WILL MOVE IN BY THIS EVENING ENDING POPS AND DECREASING CLOUDS.

A STRONG WAVE/DEVELOPING UPPER LOW WILL CROSS THE NRN ROCKIES
FRIDAY...WITH UPPER FLOW BECOMING ACTIVE FROM THE SW. SURFACE LOW
WILL DEVELOP SOMEWHERE FROM NE WY TO NW SD. SW WIND WILL CONTINUE
WARMING TREND WITH HIGHS REACHING THE MID 60S TO UPPER 70S. AS
SURFACE LOW SLIDES INTO ND...A COLD FRONT WILL ADVANCE ACROSS THE
CWA FRIDAY NIGHT. UNSTABLE ATMOSPHERE AHEAD OF THE FRONT WILL ALLOW
FOR ISOLATED CONVECTION TO DEVELOP IN THE AFTERNOON...WITH
INCREASING CHANCES AS THE FRONT PUSHES THROUGH. 00Z NAM SHOWS
SB/MLCAPE APPROACHING 500-1000 J/KG. SHEAR WILL BE RELATIVELY
WEAK...BUT ENOUGH FOR A STORM OR TWO TO BECOME STRONG. THE FRONT
WILL MAKE IT TO SCNTRL SD AFTER 06Z AND CLEAR THE CWA LATE FRIDAY
NIGHT.


&&

.LONG TERM...SATURDAY THROUGH WEDNESDAY
ISSUED AT 258 AM MDT THU APR 17 2014

MODELS ARE IN GOOD AGREEMENT WITH UPPER LEVEL/THERMAL RIDGE
IMPACTING THE CWA FOR SATURDAY THROUGH TUESDAY. THE RIDGE WILL
BREAKDOWN FOR THE MIDDLE OF NEXT WEEK BRINGING POPS TO THE REGION
STARTING TUESDAY AND PERSISTING THROUGH PERHAPS THURSDAY. MOST
GUIDANCE SHOWS A NOTABLE UPPER LEVEL TROUGH MOVING THROUGH THE
MIDDLE/END OF NEXT WEEK...BUT DIFFER WITH TIMING/DISPOSITION OF
SHORTWAVES/UPPER LOWS. THEY DO ALL TEND TO SHOW THE MAIN SYSTEM
WRAPPING UP NORTH OF THE CWA WHICH WOULD KEEP US ON THE WARMER
SIDE...BRINGING APRIL SHOWERS FOR MAY FLOWERS. STAY TUNED.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 518 AM MDT THU APR 17 2014

AREAS MVFR CIGS ARE EXPECTED THIS MORNING OVER NORTHEAST
WYOMING/WESTERN SD. A FEW -SHSN ARE POSSIBLE WITH LOCAL IFR VSBYS
THROUGH EARLY THIS MORNING. LOCAL LIFR/IFR CIGS/VSBYS ARE EXPECTED
OVER THE BLACK HILLS DUE TO AREAS OF BR/FG AND CLOUDS INTERSECTING
TERRAIN. CONDITIONS WILL IMPROVE TO VFR THIS AFTERNOON...LASTING
THROUGH TONIGHT.

&&

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

$$

SHORT TERM...13
LONG TERM...HELGESON
AVIATION...HELGESON