000
FXUS63 KUNR 170011
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
611 PM MDT SUN JUN 16 2013

.UPDATE...
ISSUED AT 543 PM MDT SUN JUN 16 2013

COMPACT SHORTWAVE AND ASSOCIATED THUNDERSTORMS OVER NE CONTINUE TO
SHIFT SE AWAY FROM THE AREA. LINGERING OUTFLOW BUBBLE IN PLACE HAS
SUPPORTED A FEW SHOWERS ALONG ITS EDGE EARLIER WITH PEAK HEATING.
HOWEVER...STABILIZING BL WILL BRING THIS ACTIVITY TO AN END.
ATTENTION TURNS TOWARD ANOTHER MID LEVEL SHORTWAVE PROPAGATING
EAST ACROSS SOUTHERN MT AND WY. FORECAST MODELS SUPPORT POTENTIAL
THUNDERSTORM DEVELOPMENT LATE TONIGHT OVER THE WESTERN FA WITH
INCREASING SOUTHERLY FLOW AT THE BASE OF STEEP MID-LEVEL LAPSE
RATES. FAIRLY MOIST LAYER EXPECTED TO REMAIN IN PLACE JUST ABOVE
THE BL GIVEN VEERING LL FLOW THIS EVENING. IN ADDITION...RESIDUAL
OUTFLOW BUBBLE MAY PROVIDE AN ADDITIONAL FORCING MECHANISM AS LL
FLOW VEERS/INCREASES ALOFT LATER TONIGHT. CERTAINLY A POTENTIALLY
UNSTABLE AIRMASS ALOFT GIVEN ONGOING UPSTREAM HIGH BASED
CONVECTION...ESP WHEN COUPLED WITH LINGERING LL MOISTURE.
HENCE...HAVE ADDED A LOW POP FOR THUNDERSTORMS NE WY AND FAR
WESTERN SD AFTER 06Z. ALL ELSE IN GOOD SHAPE.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 210 PM MDT SUN JUN 16 2013

UPPER LEVEL ANALYSIS HAS WEAK RIDGE OVER THE ROCKIES WITH UPPER
TROF SHIFTING EAST ACROSS SOUTHERN CANADA. FAIRLY FAST ZONAL FLOW
IN PLACE ACROSS THE NORTHERN PLAINS. EARLY MORNING CONVECTION HAS
PERSISTED ACROSS FAR SOUTHERN SOUTH DAKOTA...WITH NEW STORMS
DEVELOPING OFF THE BLACK HILLS AND MOVING SOUTHEAST. AT THE
SURFACE...WEAK COLD FRONT CONTINUES TO SETTLE SOUTH ACROSS THE
AREA...HELPING TO SHIFT CONVECTION INTO NEBRASKA. TEMPERATURES ARE
IN THE 70S...WITH SOME 60S ACROSS SOUTH CENTRAL SOUTH DAKOTA.

FOR TONIGHT...LINGERING CHANCES FOR SHOWERS AND STORMS WILL SHIFT
FURTHER SOUTH AND EAST TOWARD SOUTH CENTRAL SD BY EARLY EVENING
AND SHOULD MOVE OUT/DISSIPATE BY LATE EVENING AS FRONT SLIDES
SOUTH OF THE CWA. LOW TEMPERATURES WILL FALL INTO THE 40S AND 50S.

ON MONDAY...THE BETTER CHANCES FOR PCPN WILL SHIFT TO NORTHEASTERN
WY AND PORTIONS OF SOUTHWESTERN SD. WEAK HIGH PRESSURE MOVES ACROSS
THE NORTHERN PLAINS DURING THE DAY AND SOUTHEASTERLY WINDS INCREASE
OVER WESTERN AREAS...BRINGING INCREASING LOW LEVEL MOISTURE. WEAK
SHORTWAVE ENERGY WILL PASS OVER THE BUILDING RIDGE AND WILL LIKELY
BE ENOUGH TO GET AT LEAST ISOLATED SHOWERS AND STORMS GOING...
ESPECIALLY OVER THE BLACK HILLS AND THE HIGHER TERRAIN IN EASTERN
WY. THE THREAT FOR SEVERE STORMS IS NOT AS HIGH AS TODAY...BUT A
STRONGER STORM OR TWO CERTAINLY LOOKS POSSIBLE IN THE AFTERNOON.
HIGHS WILL MOSTLY BE IN THE 70S.

PRECIP CHANCES SLIDE SOUTHEAST MONDAY NIGHT AS UPPER RIDGE BUILDS
INTO THE PLAINS. A FAIRLY QUIET NIGHT IN STORE WITH LOWS FALLING
INTO THE 40S AND 50S.

&&

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 210 PM MDT SUN JUN 16 2013

UPPER RIDGE WILL BUILD INTO THE NRN PLAINS BY MID WEEK AS
UPPER LOW DIGS INTO THE PAC NW. MODELS ARE SUGGESTING A PRETTY
SIGNIFICANT WAVE MOVING THROUGH THE RIDGE LATE TUESDAY/TUESDAY
NIGHT AND MAY BRING A GOOD CHANCE OF TSTMS TO THE AREA. WEAKER
WAVES WILL THEN MOVE THROUGH THE RIDGE AND PROVIDE NEARLY DAILY
CHANCES FOR TSTMS THROUGH MID WEEK. UPPER RIDGE AXIS SHIFTS EAST
OF THE REGION LATE IN THE WEEK AS UPPER LOW MOVES INTO THE NRN
ROCKIES...WITH SOUTHWEST FLOW ALOFT BRINGING BETTER CHANCES FOR
TSTMS BACK TO THE REGION. TEMPS WILL BE NEAR TO SLIGHTLY ABOVE
AVERAGE EXPECTED THROUGH THE PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 543 PM MDT SUN JUN 16 2013

THE NEXT ADVANCING SHORTWAVE WILL PROPAGATE EAST IN THE PERIOD AND
SUPPORT INCREASING CHANCES FOR SHRA AND TS OVER NE WY AND FAR
WESTERN SD. THUNDERSTORMS WILL BE POSSIBLE JUST AFTER 06Z TONIGHT
THERE. HOWEVER...BEST CHANCES WILL BE MONDAY AFTERNOON.
OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THE PERIOD /SAVE IN
AND NEAR TS/ WITH VEERING LL FLOW.

&&

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

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...JOHNSON
AVIATION...JC