FXUS63 KUNR 030922
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
222 AM MST THU DEC 3 2009

.DISCUSSION...CURRENT WATER VAPOR SATELLITE IMAGERY SHOWS UPPER 
TROF DIGGING OVER THE NORTHERN PLAINS WITH THE TROUGH AXIS JUST 
EAST OF THE BIGHORN MOUNTAINS. EMBEDDED SHORTWAVES ROTATING THROUGH 
THE TROF COMBINED WITH STEEP LAPSE RATES WILL ALLOW THE LIGHT SNOW 
SHOWERS TO CONTINUE THROUGH MOST OF THE DAY TODAY. WON/T SEE MUCH IN 
THE WAY OF ACCUMULATION...BUT MIGHT SEE ANOTHER INCH OR TWO IN THE 
HIGHER ELEVATIONS OF THE BLACK HILLS. 

CURRENT SURFACE ANALYSIS HAS TEMPERATURES RANGING FROM ZERO TO THE 
UPPER TEENS. DON/T EXPECT TEMPERATURES TO CHANGE MUCH FOR HIGHS 
TODAY FROM THE CURRENT READINGS DUE TO COLD AIR ADVECTION AND CLOUD 
COVER. THE BRISK NORTHWEST WINDS WILL CONTINUE THROUGH THE DAY. WILL 
SEE SOME LINGERING FLURRIES TONIGHT...BUT FOR THE MOST PART THINGS 
WILL SETTLE DOWN AS THE UPPER LOW AND TROF MOVES EAST. 

MODELS ARE IN FAIRLY GOOD AGREEMENT WITH A SERIES OF SHORTWAVES 
EMBEDDED IN THE FLOW PASSING THROUGH THE AREA FOR THE ENTIRE SHORT 
TERM PERIOD. MAIN DIFFERENCE BETWEEN THEM IS IN THE MOISTURE 
AVAILABLE TO PRODUCE SNOW. MOISTURE WILL BE LIMITED WITH THESE 
SHORTWAVES...HOWEVER I WILL LEAN MORE TOWARD THE WETTER GFS SOLUTION 
AND INCLUDE THE POSSIBILITY OF SOME LIGHT SNOW AGAIN ON SATURDAY AND 
SATURDAY NIGHT. MODELS ARE VERY CLOSE WITH TEMPERATURES...SO WILL 
NOT DEVIATE MUCH FROM GUIDANCE TEMPS. 

EXTENDED...CYCLONIC FLOW ALOFT WILL REMAIN ACROSS THE AREA BRINGING 
UNSETTLED WEATHER FOR THE FIRST HALF OF NEXT WEEK. HAVE CONTINUED 
WITH DAILY LOW POPS FOR SNOW...WITH THE HIGHEST POPS ON SUNDAY AS AN 
UPPER LOW SWINGS THROUGH. IT STILL APPEARS AS THOUGH ACCUMULATIONS 
WILL REMAIN LIGHT. TEMPERATURES WILL BE VERY COLD WITH HIGHS IN THE 
TEENS ACROSS MOST AREAS AND LOWS GENERALLY BETWEEN ZERO AND 10 
ABOVE. MODELS ARE HINTING AT A SLIGHT WARM UP BY MIDWEEK BUT WITH 
TEMPERATURES STILL WELL BELOW SEASONAL AVERAGES.

&&

.AVIATION...MAINLY MVFR CONDITIONS WITH ISOLATED TO SCATTERED SNOW 
SHOWERS ARE EXPECTED TODAY. SOME AREAS OF IFR ARE EXPECTED AS 
WELL...ESPECIALLY ACROSS NORTHEASTERN WYOMING...NORTHWEST SOUTH 
DAKOTA...AND OVER THE BLACK HILLS.

&&

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

$$