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000
FXUS63 KUNR 211956
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
156 PM MDT TUE MAY 21 2013

.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 151 PM MDT TUE MAY 21 2013

19Z UPPER LEVEL ANALYSIS SHOWS A LOW OVER EASTERN
SOUTH DAKOTA...RIDGING OVER THE ROCKIES...AND ANOTHER LOW MOVING IN
FROM THE PACIFIC. CLOUDS BLANKET THE DAKOTAS...AND SHOWERS ARE
ROTATING COUNTERCLOCKWISE AROUND THE LOW. SHOWERS HAVE DIMINISHED
QUITE A BIT DURING THE MORNING...AND WILL CONTINUE TO DO SO
THROUGHOUT THE EVENING AS THE LOW PUSHES EASTWARD. WINDS WILL ALSO
CONTINUE TO DECREASE.

LOWS TONIGHT WILL BE IN THE LOWER 30S TO LOWER 40S. SHOWERS ARE
POSSIBLE OVERNIGHT MAINLY OVER SOUTH DAKOTA...WITH DECREASING
CHANCES TOWARDS MORNING. A FEW LIGHT SNOW SHOWERS ARE POSSIBLE AGAIN
OVER THE BLACK HILLS.

THERE IS A SLIGHT CHANCE OF LINGERING SHOWERS WEDNESDAY MORNING
BEFORE HIGH PRESSURE AND DRY AIR MOVE INTO THE REGION. CLOUDS WILL
BEGIN TO DISSIPATE...AND TEMPS WILL WARM INTO THE MID 50S AND MID
60S. THE HILLS MAY SEE SOME AFTERNOON SHOWERS...AS LIFTED INDICES
THERE BECOME NEGATIVE. LOWS WEDNESDAY NIGHT WILL BE MAINLY IN THE
40S...WITH 30S IN THE BLACK HILLS.

&&

.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 151 PM MDT TUE MAY 21 2013


UPPER LEVEL RIDGE PEAKS OVER THE NORTHERN PLAINS THURSDAY BRINGING
DRY AND WARMER WEATHER TO THE CWA. LOW PRESSURE WILL DEVELOP OVER
WESTERN WY AS DEEP UPPER LEVEL TROUGH/LOW OVER THE NORTHWEST US
SPINS AND SOUTHWEST FLOW DEVELOPS ON BACK SIDE OF UPPER LEVEL RIDGE.
GRADIENT WILL SUPPORT BREEZY/WINDY AREAS...ESPECIALLY OVER NORTHEAST
WY/WESTERN SD. HAVE REMOVED POPS GIVEN DRIER AIR AND SUBSIDENCE
UNDER RISING HEIGHT REGIME. TEMPERATURES WILL BE SLIGHTLY BELOW
GUIDANCE GIVEN RECENT WET WEATHER.

UPPER LEVEL RIDGE SLOWLY MOVES INTO THE MIDWEST FRIDAY THROUGH
TUESDAY. SOUTHWEST FLOW ALOFT DEVELOPS OVER THE AREA WITH A SERIES
OF SHORTWAVES MOVING THROUGH. QUASI-STATIONARY LEE TROUGH DEVELOPS
FROM MT INTO SOUTHEAST WY/WESTERN NE. PERSISTENT SOUTHEASTERLY FLOW
AHEAD OF THE SURFACE TROUGH WILL BRING INCREASINGLY MOIST TD/S INTO
THE CWA WHICH WILL RESULT IN A DAILY CHANCE FOR TSRA...ALONG A
POTENTIAL ACTIVE SEVERE WEATHER PATTERN...ESPECIALLY SUNDAY INTO
EARLY NEXT WEEK BASED ON PATTERN RECOGNITION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1102 AM MDT TUE MAY 21 2013

SCATTERED/NUMEROUS SHRA WILL CONTINUE ACROSS MUCH OF THE AREA
THIS AFTERNOON...WITH MVFR/IFR CONDITIONS PERSISTING. ONE
EXCEPTION WILL BE VFR CONDITIONS AT KGCC/PORTIONS NORTHEAST WY THIS
AFTERNOON. SHRA WILL DECREASE IN COVERAGE THIS AFTERNOON AND
ESPECIALLY THIS EVENING FROM WEST TO EAST AS LOW PRESSURE PUSHES
AWAY FROM THE REGION. GUSTY NORTHWESTERLY WINDS WILL SLOWLY
DIMINISH. MVFR/IFR CIGS WILL REMAIN OR REDEVELOP ACROSS THE CWA
TONIGHT AS BOUNDARY LAYER COOLS.


&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...HELGESON
AVIATION...HELGESON