Area Forecast Discussion
Issued by NWS Rapid City, SD

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KUNR 261737
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1037 AM MST WED NOV 26 2014

.UPDATE...
ISSUED AT 1028 AM MST WED NOV 26 2014

UPPER LEVEL ANALYSIS HAS A TROF OVER THE UPPER MIDWEST WITH A
RIDGE OVER THE FAR SW CONUS. FAST NORTHWEST FLOW CONTINUES OVER
THE NORTHERN PLAINS IN BETWEEN THESE TWO FEATURES...WITH 150KT
JET ACROSS THE WESTERN DAKOTAS. SKIES ARE CLOUDY WITH ON AND OFF
LIGHT SNOW ACROSS MUCH OF THE FORECAST AREA. AT THE
SURFACE...ARCTIC HIGH IS LOCATED ACROSS SOUTHERN CANADA WITH WEAK
LOW/TROF ACROSS CENTRAL WYOMING. TEMPERATURES ARE IN THE 20S WITH
GENERALLY LIGHT WINDS.

SHORT TERM FORECAST IS IN DECENT SHAPE WITH LIGHT SNOW EXPECTED
ACROSS MUCH OF THE FORECAST AREA THROUGH THIS AFTERNOON. LITTLE
ACCUMULATION IS EXPECTED. WARMER AIR WILL BEGIN TO MOVE INTO
WESTERN AREAS LATE THIS AFTERNOON AND EVENING...WHICH COULD BRING
SOME VERY LIGHT FREEZING RAIN TO PORTIONS OF NORTHEAST
WYOMING...THE BLACK HILLS...INTO NORTHWEST SOUTH DAKOTA.

&&

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
ISSUED AT 249 AM MST WED NOV 26 2014

LATEST WATER VAPOR IMAGES AND UPPER ANALYSIS SHOW UPPER TROUGH
OVER THE MIDWEST WITH A RIDGE OVER THE PACIFIC COAST. FAST 150KT
JET FLOW IS DIVING INTO THE FORECAST AREA FROM THE NORTHWEST. THE
NW-SE ORIENTED BAROCLINIC ZONE OVER THE WESTERN PART OF THE CWA
WILL INTENSIFY TODAY WITH INCREASED MID-HIGH LEVEL WARM ADVECTION
ABOVE THE COLDER AIR AT THEE SURFACE. THE BAROCLINIC ZONE WILL
GRADUALLY MOVE NORTHEASTWARD TODAY AND TONIGHT. FRONTOGENETICAL
FORCING AND NEARLY SATURATED PROFILES WILL LEAD TO PERIODS OF
LIGHT SNOW OR FLURRIES OVER NERN WY AND PARTS OF FAR WESTERN SOUTH
DAKOTA TODAY. THE PRECIPITATION WILL SPREAD NEWD TONIGHT AS UPPER
HEIGHTS CONTINUE TO BUILD AND LOW-MID LEVEL WARM ADVECTION
INTENSIFIES. SREF PTYPE PROBABILITIES AND NAM VERTICAL PROFILES
SUPPORT A CHANCE OF SNOW WITH A SLIGHT CHANCE OF FZRA OVER PARTS
OF NERN WY AND NWRN SD LATE TONIGHT INTO THU MORNING. THERE WILL
BE A WIDE SPREAD OF TEMPERATURES ON THURSDAY AS THE COLDER AIR
RETREATS TO THE EAST AND WARMER AIR MOVES IN FROM THE SOUTHWEST.
HIGHS ARE EXPECTED TO RANGE FROM AROUND 30F TOWARD NORTH CENTRAL
SOUTH DAKOTA WITH HIGHS AROUND 50F OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. THE PRECIPITATION OVER FAR
NORTHWESTERN SOUTH DAKOTA IN THE MORNING WILL MOVE AWAY FROM THE
AREA BY AFTERNOON...LEAVING DRY WEATHER AND VARIABLE CLOUD COVER
FOR THURSDAY AFTN.

&&

.LONG TERM...FRIDAY THROUGH TUESDAY
ISSUED AT 249 AM MST WED NOV 26 2014

UPPER FLOW WILL BECOME MORE ZONAL FOR THE END OF THE
WEEK AS WEAK RIDGING BREAKS DOWN AHEAD OF THE NEXT PACIFIC TROUGH.
WARMER AIRMASS OVER THE REGION FRIDAY WILL BRING TEMPS WELL ABOVE
SEASONAL AVERAGES. THE NEXT TROUGH WILL CROSS THE PACIFIC NORTHWEST
SATURDAY WITH STRONG COLD FRONT CROSSING THE AREA. THERE IS SOME
DISAGREEMENT BETWEEN THE ECM/GFS WITH THE TIMING OF THE FRONT. THE
GFS HAS TRENDED WARMER DELAYING THE FRONTAL PASSAGE TILL SATURDAY
NIGHT. THE ECM CONTINUES TO SHOW THE FRONT PASSING DURING THE DAY
SATURDAY. HAVE INCREASED TEMPS SOME TO ACCOUNT FOR GFS...BUT
CONFIDENCE IS LOW AT THIS TIME. SOME LIGHT SNOW IS POSSIBLE SAT
NIGHT INTO POSSIBLY SUNDAY...BUT MINIMAL QPF IS EXPECTED. COLDER AIR
WILL KEEP TEMPS MUCH COLDER EARLY NEXT WEEK...BUT SOME MODIFYING IS
POSSIBLE TOWARD MIDWEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z THURSDAY
ISSUED AT 1001 AM MST WED NOV 26 2014

SNOW WILL CONTINUE ACROSS MUCH OF THE AREA TODAY BRINGING
WIDESPREAD MVFR/IFR CONDITIONS...AND CONTINUE THROUGH TONIGHT.
SOME LIFR CONDITIONS EXPECTED NEAR THE BLKHLS AREA.


&&

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

$$

UPDATE...15
SHORT TERM...10
LONG TERM...13
AVIATION...POJORLIE






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.