247 
FXUS63 KUNR 301542
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
942 AM MDT MON JUL 30 2012

.UPDATE...THE ISOLATED SHOWERS THAT WERE OVER PARTS OF NERN
WY...THE BLACK HILLS AND SWRN SD HAVE DISSIPATED. HAVE UPDATED THE
FORECAST TO REFLECT THAT. HAVE ALSO LOWERED HIGH TEMPS A COUPLE OF
DEGREES DUE TO EASTERLY WINDS NORTH OF THE SFC TROUGH.

&&

AVIATION...12Z TAFS
ISOLD/SCT TSRA ARE EXPECTED TO DEVELOP OVER NERN WYO/BLKHLS AND
SPREAD INTO THE SD PLAINS THIS AFTERNOON AND EVENING. STRONG WIND
GUSTS MAY DEVELOP INVOF SOME STORMS.

&&

.PREV DISCUSSION... /ISSUED 228 AM MDT MON JUL 30 2012/ 

DISCUSSION...HIGH PRESSURE OVER THE CENTRAL UNITED STATES WILL
CONTINUE TO CONTROL OUR WEATHER THROUGH THE FORECAST PERIOD.
PREDICTABILITY OF INDIVIDUAL SHORT-WAVE TROUGHS WILL BE LOW...BUT
THE PRESENCE OF A MOISTURE PLUME WILL FOSTER THUNDERSTORM CHANCES
EACH DAY.

EARLY MORNING OBSERVATIONS INDICATED A SHORT-WAVE TROUGH MOVING
TOWARD NORTHERN MN...WITH A WEAK SURFACE FRONT TRAILING SOUTHWEST
ACROSS SD AND THEN NORTHWEST INTO MT. A FEW WEAK SHOWERS WERE
NOTED ON THE NORTHERN EDGE OF THE MOISTURE PLUME THAT EXTENDED
ACROSS THE CWA...AND SOME LIGHTNING ALSO HAS BEEN NOTED IN THIS
AREA WHERE MUCAPE WAS 100-500 J/KG.

FOR TODAY THROUGH TUESDAY THERE WILL BE PERIODIC WEAK...SUBTLE
SHORT-WAVE TROUGHS THAT TRAVERSE THE PERIPHERY OF THE RIDGE. HIGH
POPS ARE NOT WARRANTED...BUT THERE WILL BE CONVECTIVE ACTIVITY
OVER PARTS OF THE CWA MOST OF THE TIME. MLCAPE WILL BE 500-1000
J/KG TODAY...RISING TO 750-1500 J/KG TUESDAY. VERTICAL WINDS SHEAR
WILL BE WEAK...SO UNORGANIZED STORMS WITH LIMITED SEVERE POTENTIAL
ARE EXPECTED. PULSE-TYPE SEVERE WINDS WOULD BE MOST LIKELY.

THE UPPER RIDGE WILL FLATTEN WEDNESDAY AS A MORE SUBSTANTIAL SHORT-
WAVE TROUGH MOVES ACROSS SOUTHERN SASKATCHEWAN. Q-G FORCING WILL
BE A BIT MORE FAVORABLE FOR A SMALL MCS OR TWO WEDNESDAY AFTERNOON
AND EVENING...ESPECIALLY EAST OF THE BLKHLS...WHERE A WEAK SURFACE
BOUNDARY WILL RESIDE. THE SEVERE POTENTIAL STILL LOOKS RELATIVELY
LOW.

TEMPERATURES WILL REMAIN ABOVE AVERAGE THROUGH THE PERIOD GIVEN
THE STRONG UPPER RIDGING...HOWEVER...THE MOISTURE PLUME AND AREAS
OF MIDLEVEL CLOUDS WILL LIMIT HIGH TEMPERATURES FROM REACHING
THEIR FULL POTENTIAL.

EXTENDED...MONSOONAL FLOW PATTERN WILL CONTINUE INTO THURS...WITH 
PRECIP CHANCES CONTINUING AND TEMPS REMAINING WELL ABOVE AVERAGE. ON 
FRIDAY...MODELS CONTINUE TO SWING A TROF AROUND HUDSON BAY LOW INTO 
THE NORTHERN PLAINS...AND ARE ACTUALLY STARTING TO CLOSE IT OFF OVER 
THE SRN PRAIRIE PROVINCES. WITH THIS FEATURE MOVING THROUGH THE 
REGION WILL KEEP SOME POPS IN THRU FRI NIGHT...ALONG WITH SLIGHTLY 
COOLER...THOUGH STILL ABOVE AVERAGE...TEMPERATURES. MODELS THEN 
BUILD RIDGE INTO THE WRN CONUS SHUTTING OFF THE MONSOONAL FLOW OVER 
OUR AREA. WILL HAVE TO KEEP AN EYE ON THIS TO SEE IF IT PANS 
OUT...BUT FOR NOW WILL KEEP THINGS DRY FOR NEXT WEEKEND.

&&

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

$$