050
FXUS63 KUNR 291019
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
315 AM MST SUN NOV 29 2009
DISCUSSION
10Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE FROM THE
NORTHERN ROCKIES ACROSS WYOMING AND INTO THE NEBRASKA PANHANDLE.
UPPER LEVEL ANALYSIS SHOWS AN UPPER TROUGH MOVING FROM THE DAKOTAS
INTO MINNESOTA WITH A HIGH AMPLITUDE UPPER RIDGE BUILDING OVER THE
PACIFIC NORTHWEST. KUDX RADAR IS CURRENTLY SHOWING SOME WEAK RETURNS
OVER WESTERN SOUTH DAKOTA...MAINLY VIRGA...THOUGH AN ISOLATED
FLURRY MAY BE REACHING THE GROUND.
THE AREA OF CLOUDS WILL SLIDE OFF TO THE SOUTHEAST TODAY...FOLLOWED
BY MOSTLY SUNNY SKIES AND HIGHS IN THE 40S ON THE PLAINS. BREEZY
CONDITIONS EXPECTED ON THE PLAINS OF WRN SD THIS AFTN.
MILDER AIR WILL MOVE INTO THE AREA LATER TONIGHT AND MONDAY AS THE
UPPER RIDGE BUILDS IN FROM THE WEST. HIGHS ON MONDAY WILL
REACH INTO THE 50S AT MOST LOCATIONS UNDER MOSTLY SUNNY SKIES.
THE UPPER RIDGE AXIS WILL SHIFT EAST ON TUESDAY AS A COLD FRONT
PUSHES THROUGH AT THE SURFACE. THERE WILL BE A SLIGHT CHANCE OF SNOW
SHOWERS. VERY WINDY CONDITIONS ARE EXPECTED BEHIND THE COLD FRONT ON
THE PLAINS OF WESTERN SOUTH DAKOTA ON TUESDAY.
EXTENDED...A HIGH AMPLITUDE TROUGH CENTERED ACROSS THE GREAT LAKES
EXTENDING SOUTH THROUGH THE MISSISSIPPI VALLEY WILL BRING MUCH
COLDER AIR TO THE CENTER OF THE COUNTRY...EXTENDING AS FAR WEST AS
THE CWA. MODELS SHOW DRY AIR FROM HIGH PRESSURE DROPPING SOUTHEAST
FROM MONTANA/CENTRAL CANADA. GIVEN THIS DRY AIR...HAVE STARTED
DECREASING AREAL COVERAGE OF MINIMAL POPS ALREADY IN THE FORECAST
WEDNESDAY...AND HAVE REMOVED POPS WED NIGHT/THU. BELOW SEASONABLE
TEMPS ARE EXPECTED THROUGH THURSDAY. AFTER A SLIGHT WARMUP
FRIDAY...THE NEXT COLD FRONT AND UPPER TROUGH WILL AFFECT THE AREA
THROUGH THE WEEKEND BRINGING COLDER TEMPERATURES AND CHANCES FOR
PRECIPITATION.
AVIATION
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
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