919 
FXUS63 KUNR 181148
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
548 AM MDT SAT AUG 18 2012

.DISCUSSION...COMPACT SHORTWAVE MOVING THROUGH EASTERN SOUTH
DAKOTA HAS SHIFTED EAST ENOUGH TO WARRANT REMOVAL OF ISOLATED
SHOWERS/STORMS FROM SOUTH CENTRAL SOUTH DAKOTA THIS MORNING. 

&&

.PREV DISCUSSION... /ISSUED 222 AM MDT SAT AUG 18 2012/ 

DISCUSSION...UPPER LEVEL ANALYSIS HAS RIDGE OVER THE WESTERN
CONUS WITH LARGE TROF OVER THE GREAT LAKES REGION...RESULTING IN
NORTHWESTERLY FLOW OVER THE NORTHERN PLAINS. WEAK UPPER SHORT
WAVE SLIDING THROUGH THE EASTERN DAKOTAS IS PRODUCING SOME
ISOLATED SHOWERS/STORMS ACROSS CENTRAL SOUTH DAKOTA ATTM. 20Z
SURFACE ANALYSIS HAS WEAK LOW PRESSURE OVER SOUTH CENTRAL SOUTH
DAKOTA WITH HIGH PRESSURE BUILDING IN FROM THE NORTHWEST.
TEMPERATURES ARE IN THE 50S TO MID 60S WITH GENERALLY LIGHT NORTH
TO NORTHWEST WINDS.

FOR TODAY...UPPER SHORTWAVE AND ASSOCIATED WEAK CONVECTION OVER
CENTRAL SOUTH DAKOTA WILL SHIFT QUICKLY EAST THIS MORNING. A QUIET
DAY IS IN STORE TODAY WITH TEMPERATURES REMAINING SLIGHTLY BELOW
AVERAGE...IN THE 70S TO LOWER 80S UNDER SUNNY SKIES. TEMPERATURES
TONIGHT WILL FALL INTO THE 40S TO LOWER 50S.

FOR SUNDAY...SURFACE HIGH PRESSURE SLIDES EAST AS UPPER RIDGE AXIS
BUILDS OVER THE NORTHERN ROCKIES. HIGH TEMPERATURES WILL WARM
SLIGHTLY...INTO THE MID 70S TO MID 80S. SKIES REMAIN MOSTLY CLEAR
INTO SUNDAY NIGHT WITH LOWS FALLING INTO THE MID 40S TO MID 50S.

ON MONDAY...SURFACE HIGH PRESSURE SETTLES OVER MINNESOTA AS UPPER
RIDGE BUILDS INTO THE NORTHERN PLAINS. SOUTHERLY RETURN FLOW AND
BUILDING HEIGHTS WILL ALLOW TEMPERATURES TO FINALLY WARM TO NEAR
AVERAGE LEVELS...IN THE UPPER 70S TO UPPER 80S. LOWS MONDAY NIGHT
WILL MAINLY BE IN THE 50S.

EXTENDED...AN UPPER LEVEL RIDGE WILL CONTINUE TO DOMINATE THE 
WEATHER TUESDAY WITH DRY AND WARM CONDITIONS. A SHORTWAVE TROUGH 
WILL MOVE INTO THE REGION FOR WED/THU OF NEXT WEEK BRINGING
CHANCES FOR TSRA. FLOW WILL THEN BECOME WEST WITH A WEAK UPPER
LEVEL RIDGE FOR THE END OF NEXT WEEK.

AVIATION...12Z TAFS
VFR CONDITIONS ARE EXPECTED THROUGH TONIGHT.

&&

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

$$

SHORT TERM...15
LONG TERM....HELGESON
AVIATION...HELGESON