000
FXUS63 KUNR 292004
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
204 PM MDT FRI AUG 29 2008
.DISCUSSION...CURRENT WATER VAPOR IMAGERY SHOWS FLAT RIDGE OVER THE
NORTHERN ROCKIES...WORKING INTO THE DAKOTAS. CLEAR SKIES AND COOL
TEMPERATURES WILL BE FOUND ACROSS THE AREA TONIGHT. SATURDAY WILL BE
A HOT AND DRY WINDY DAY ACROSS MUCH OF THE CWA. RED FLAG CONDITIONS
ARE EXPECTED OVER NORTHEAST WYOMING AND THE WESTERN SOUTH DAKOTA
PLAINS ON SATURDAY. THE NAM IS INDICATING 850 MB TEMPS AROUND 30 C
BY 00Z OVER MUCH OF WESTERN SOUTH DAKOTA AND NORTHEAST WYOMING WITH
SURFACE DEW POINTS DROPPING INTO THE 20S OVER NORTHEAST WYOMING AND
LOWER 40S OVER WESTERN SOUTH DAKOTA. HIGH TEMPERATURES WILL CLIMB
INTO THE 90S ACROSS MOST OF THE CWA WITH A FEW LOCATIONS APPROACHING
100. STRONG SOUTH WINDS WILL DEVELOP SATURDAY AFTERNOON ACROSS SOUTH
CENTRAL SOUTH DAKOTA. A WIND ADVISORY WILL PROBABLY BE NEEDED OVER
SOUTH CENTRAL SOUTH DAKOTA ON SATURDAY AFTERNOON. WINDS ARE
FORECAST TO BE OUT OF THE SOUTH AT 20 TO 30 MPH WITH GUSTS TO
AROUND 45 MPH. TROUGH WILL DIG INTO THE PACIFIC NORTHWEST SATURDAY
AFTERNOON INTO SATURDAY EVENING. A FRONTAL BOUNDARY IS EXPECTED TO
SET UP ACROSS THE WESTERN DAKOTAS AND NORTHEAST WYOMING LATE
SUNDAY AFTERNOON AS THE TROUGH DIGS INTO THE CENTRAL ROCKIES.
GUSTY SOUTH WINDS WILL AGAIN DEVELOP OVER SOUTH CENTRAL SOUTH
DAKOTA. AT THIS TIME IT APPEARS THAT A WIND ADVISORY MAY ONCE
AGAIN BE NEEDED OVER SOUTH CENTRAL SOUTH DAKOTA SUNDAY AFTERNOON.
THE FIRST SHORTWAVE IMPULSE IS EXPECTED TO EJECT OUT OF THE
CENTRAL ROCKIES AND IMPACT THE CWA SUNDAY AFTERNOON. THIS IMPULSE
WILL BRING A SLIGHT CHANCE OF THUNDERSTORMS TO WESTERN PORTIONS OF
THE CWA AS THE FRONTAL BOUNDARY REMAINS STALLED OVER FAR WESTERN
SOUTH DAKOTA. THE FRONT WILL BEGAN TO SLIDE EASTWARD ON SUNDAY
NIGHT AS ANOTHER SHORTWAVE MOVES OVER THE AREA. THIS WAVE WILL
BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO MUCH OF THE CWA
EXTENDED...UPPER TROF DEEPENS OVER THE SOUTHWESTERN US AND MOVES
INTO THE PLAINS EARLY NEXT WEEK. LATEST MODELS HAVE TROF FARTHER
SOUTH AND MOVING MORE TO THE NORTH-NORTHEAST...STAYING FARTHER WEST
THAN PREVIOUS RUNS. LARGE BAND OF PRECIPITATION ON SOUTHWESTERLY
FLOW AHEAD OF THE TROF WILL STREAM OVER THE AREA...BUT LOCATION OF
SIGNIFICANT PRECIPITATION AND DRY SLOT A LITTLE UNCERTAIN UNTIL
TRACK OF THE LOW IS MORE CONSISTENT. A COLD FRONT AHEAD OF THE LOW
WILL MOVE VERY SLOWLY ACROSS WESTERN SD...WITH A PUSH OF COLDER AIR
BEHIND IT. PRECIPITATION WILL BE SHOWERS BEHIND THE FRONT...BUT
ENOUGH INSTABILITY AHEAD OF THE FRONT FOR THUNDERSTORMS OVER CENTRAL
SD THROUGH MONDAY EVENING. AS UPPER LOW LIFTS OVER THE DAKOTAS
TUES...PRECIPITATION SHIELD MOVES NORTHWARD WITH SHOWERS LINGERING
OVER NORTHWESTERN SD TUE EVENING. ANOTHER UPPER TROF DIPS ACROSS THE
AREA THURSDAY WITH A CHANCE OF THUNDERSTORMS. TEMPERATURES WILL
COOL MONDAY DRASTICALLY BEHIND THE FRONT...AS MUCH AS 15 TO 25
DEGREES FROM SUN...THEN RETURN TO SEASONAL NORMALS MIDWEEK.
&&
.AVIATION...CLEAR SKIES WILL CONTINUE THROUGH MIDDAY SATURDAY.
SOUTHERLY WINDS WILL INCREASE OVER NERN WY OVERNIGHT...AND ACROSS
WESTERN SD SAT MORNING.
&&
.FIRE WEATHER...HOT TEMPERATURES AND LOW HUMIDITIES EXPECTED ACROSS
THE AREA SATURDAY AND SUNDAY. HIGHS WILL BE IN THE MID-UPPER 90S
ACROSS NORTHEAST WYOMING/WESTERN SOUTH DAKOTA WHILE MINIMUM RELATIVE
HUMIDITY RANGING FROM 10 PERCENT ACROSS NORTHEASTERN WYOMING TO 20
PERCENT ACROSS WESTERN SOUTH DAKOTA. AS SURFACE LOW DEVELOPS TO THE
WEST...GUSTY WINDS WILL INCREASE WITH STRONGEST WINDS ON THE PLAINS
EAST/NORTH OF THE BLACK HILLS. WITH FUELS CRITICAL...HAVE ISSUED RED
FLAG WARNING LATE SATURDAY MORNING THROUGH SATURDAY EVENING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING FROM 10 AM TO 10 PM MDT SATURDAY FOR BADLANDS
AREA-NORTHWESTERN SOUTH DAKOTA PLAINS-SOUTHWESTERN SOUTH
DAKOTA.
WY...RED FLAG WARNING FROM 10 AM TO 10 PM MDT SATURDAY FOR LOWER
ELEVATIONS OF CROOK AND WESTON COUNTIES-NORTHERN CAMPBELL-
SOUTHERN CAMPBELL.
&&
$$
