000
FXUS63 KUNR 060514
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1014 PM MST THU DEC 5 2013

.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 219 PM MST THU DEC 5 2013

WATER VAPOR IMAGERY SHOWS SHOWS AN UPPER LOW ACROSS CENTRAL CANADA
WITH CYCLONIC FLOW ACROSS THE WESTERN CONUS. SURFACE ANALYSIS SHOWS
A STRONG HUDSON BAY LOW WITH NORTHWESTERLY WINDS CONTINUING ACROSS
THE NORTHERN PLAINS AND UPPER MIDWEST. HIGHS TODAY HAVE SO FAR
REACHED BETWEEN 7 BELOW AND 7 ABOVE ZERO. THE COLDEST WIND CHILLS OF
20 TO 35 BELOW ARE ACROSS NORTHWEST TO CENTRAL SOUTH DAKOTA WHERE
WINDS HAVE BEEN PERSISTING AT 20-30 MPH. THESE WINDS WILL DECREASE
EARLY THIS EVENING AS SURFACE HIGH PRESSURE APPROACHES FROM THE
NORTHWEST. NORTHWEST WINDS OF 10 MPH ARE STILL EXPECTED TONIGHT
ACROSS NORTHWEST SOUTH DAKOTA AND WEAKER WINDS ELSEWHERE. WITH TEMPS
DROPPING TO 12 BELOW TO 25 BELOW ZERO...THESE WINDS WILL PRODUCE
WIND CHILLS OF 25 BELOW TO 35 BELOW. WILL CONTINUE THE WIND CHILL
ADVISORY THROUGH TOMORROW MORNING.

CLOUDS WILL GRADUALLY INCREASE ACROSS THE AREA FRIDAY INTO FRIDAY
NIGHT AS AN UPPER WAVE APPROACHES FROM THE WEST. OVERALL A QUIET DAY
IS EXPECTED WITH FRIGID TEMPERATURES CONTINUING. HIGHS ARE EXPECTED
TO RANGE FROM 7 BELOW TO 4 ABOVE ZERO. WINDS WILL BE UNDER 10
MPH...SO WIND CHILLS BY FRIDAY AFTERNOON ARE NOT EXPECTED TO BE AS
COLD AS TODAY OR TONIGHT. LIGHT WINDS WILL CONTINUE THROUGH FRIDAY
NIGHT...SO WILL NOT EXTEND ANY WIND CHILLS HEADLINES AT THIS TIME.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 219 PM MST THU DEC 5 2013

OMEGA BLOCKING PATTERN WILL PERSIST THROUGH THE FIRST PART OF THE
PERIOD...WITH ARCTIC AIR BEING RE-ENFORCED BY ADVECTING TROUGHS.
DEEP WESTERN CONUS UPPER TROUGH WILL BEGIN TO LIFT ENE INTO THE
PLAINS BY SATURDAY...WITH ASSOCIATED LIFT AND REFLECTED LL
SOUTHERLY FLOW SUPPORTING INCREASING CHANCES FOR LIGHT SNOW
THROUGH SUNDAY. DISTURBED NW FLOW WILL REMAIN THROUGH TUES...WITH
SOME UPSLOPE SNOW POSSIBLE IN THE NORTHERN BLACK HILLS. THE FLOW
PATTERN WILL BEGIN TO SHIFT BY MID NEXT WEEK...AS THE PERSISTENT
OMEGA BLOCK BREAKS DOWN AND WNW /MAINLY ZONAL/ FLOW SETS UP OVER
THE REGION. THIS WILL SUPPORT WARMER TEMPS AS DOWNSLOPE FLOW FROM
THE ROCKIES WILL SPREAD INTO THE REGION...EVENTUALLY SCOURING OUT
THE ARCTIC AIRMASS IN PLACE.

SAT-SUN...WESTERN CONUS TROUGH WILL SHIFT EAST AND SUPPORT
INCREASING DEEP LAYER ASCENT WITH A LL WAA RESPONSE...SUPPORTING
CHANCES FOR SNOW. DRY AIRMASS IN PLACE WITH DISMAL MOISTURE
ADVECTION WILL LIMIT AVAILABLE MOISTURE...WITH COLD TEMPS CERTAINLY
LIMITING CRYSTAL SIZE. HENCE...NOT EXPECTING MUCH IN THE WAY OF
ACCUMS...WITH MOST PLACES SEEING LESS THAN ONE INCH OF LIGHT SNOW.
SCENTRAL COULD SEE AN INCH OR 2 GIVEN PROXIMITY TO BETTER LIFT AND
MOISTURE. HAVE ADJUSTED TEMPS...MANLY SIDING TOWARD THE COLDEST
GUIDANCE GIVEN LL CAA IN AN ARCTIC AIRMASS.

MON-TUE...A CLIPPER SYSTEM WILL ADVECT EAST NORTH OF THE
REGION...GRAZING THE NORTHERN CWA. AS OF RIGHT NOW...FORECAST MODELS
ARE MAINLY SUPPORTING AN UPSLOPE SNOW RESPONSE IN THE FA...WITH THE
REMAINDER OF THE FA NOT SEEING MUCH IF ANY PRECIP. HAVE RETAINED
POPS ACROSS FAR NW SD AND THE NORTHERN BLACK HILLS...WITH A MARGINAL
TO DECENT PERIOD OF UPSLOPE FORCING POSSIBLE...ALTHOUGH MOISTURE
WILL BE LIMITED.

WED-THUR...HEIGHT RISES EXPECTED IN THE PERIOD AS FLOW TRANSITIONS TO
MANLY WESTERLY. ROCKIES DOWNSLOPE AIR WILL ADVECT INTO THE
REGION...WITH WARMER TEMPS EXPECTED. HAVE REMAINED LEARY OF WARMING
THINGS UP TO QUICKLY...WITH THE FORECAST MODELS SEEMINGLY TOO
AGGRESSIVE WITH SCOURING OUT LL ARCTIC AIR...ESP ON THE SD PLAINS.
KEPT THE WARMEST READINGS CONFINED TO THE HIGHER TERRAIN /NE WY AND
THE BLACK HILLS/.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1008 PM MST THU DEC 5 2013

VFR CONDITIONS ARE EXPECTED THROUGH MIDDAY FRIDAY UNDER STRONG
ARCTIC HIGH PRESSURE. ST WILL DEVELOP LATE FRIDAY AFTERNOON OVER
WY AND THEN INTO SOUTHWESTERN SD FRIDAY EVENING. MVFR CIGS WILL
RESULT WITH -SN POSSIBLE...LOCAL IFR CIGS ARE EXPECTED OVER
NORTHEAST WY/HIGHER BLACK HILLS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL NOON MST /1 PM CST/ FRIDAY FOR SDZ001-
     002-012>014-024>032-041>044-046-047-049-072>074.

WY...WIND CHILL ADVISORY UNTIL NOON MST FRIDAY FOR WYZ054>058-071.

&&

$$

SHORT TERM...13
LONG TERM...JC
AVIATION...HELGESON