Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 231722
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1022 AM MST SUN NOV 23 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 225 AM MST SUN NOV 23 2014

AT 08Z THE PACIFIC COLD FRONT HAD ALMOST COMPLETELY
MOVED OUT OF THE EASTERN EXTREMITIES OF THE FORECAST AREA.  THE
NE-SW BAND OF VERY LIGHT PRECIPITATION ACROSS WEST CENTRAL SOUTH
DAKOTA IS LIKELY THE RESULT OF MID LEVEL FRONTOGENESIS BEHIND THE
MAIN UPPER VORTICITY LOBE.  SURFACE TEMPERATURES WOULD SUPPORT THIS
BEING MOSTLY LIQUID PRECIP AT THIS TIME.  IR SATLT IMAGERY SEEMS TO
INDICATE THERE IS PROBABLY SOME VERY LIGHT PRECIPITATION OVER PARTS
OF SOUTHEASTERN MONTANA AND NORTHEAST WYOMING WHICH ISN`T SHOWING UP
ON RADAR IMAGERY BECAUSE THE TOPS ARE TOO LOW.

TODAY...THIS INSTABILITY PRECIP RESULTING FROM COLD ADVECTION ALOFT
WILL LIKELY CONTINUE THROUGH MOST OF THE DAY AND FILL IN BEHIND THE
FRONTAL PRECIP BY MID MORNING. ACCUMULATIONS SHOULD BE MINIMAL IN
THE LOWER ELEVATIONS...BUT A FEW INCHES OF NEW SNOW ARE POSSIBLE IN
THE HIGHER ELEVATIONS OF THE BLKHLS. THE MAIN WEATHER STORY WILL BE
THE STRONG NORTHERLY WINDS EXPECTED TO DEVELOP BEHIND THE UPPER
TROUGH EARLY THIS AFTERNOON. THE STRONGEST GRADIENT AND WIND SPEEDS
ARE EXPECTED BEWEEN 18Z AND 21Z OVER THE WESTERN PLAINS AND NORTH
AND NORTHEAST FOOTHILLS.

TONIGHT AND MONDAY...THE PATTERN WILL REMAIN A FAIRLY CONSTANT
NORTHWEST FLOW ALOFT WITH OCCASIONAL WEAK MID OR UPPER LEVEL
IMPULSES CROSSING THE REGION. A SLIGHT CHANCE OF MEASURABLE SNOW
WILL REMAIN IN THE FORECAST THROUGH MONDAY AND BEYOND.  MONDAY IS
EXPECTED TO BE THE COOLEST DAY OF THE WEEK WITH HIGHS ONLY REACHNG
THE LOW TO MID 30S MONDAY AFTERNOON.

&&

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 225 AM MST SUN NOV 23 2014

AN ACTIVE PATTERN ASSOCIATED WITH DEEP CYCLONIC FLOW
ALOFT WILL CONTINUE ACROSS THE NORTHERN PLAINS THROUGH MIDWEEK.
SEVERAL WEAK DISTURBANCES WITHIN NORTHWEST FLOW WILL SLIDE
THROUGH...BRINGING A GOOD DEAL OF CLOUDINESS AND CHANCES FOR SNOW
SHOWERS AT TIMES THROUGH WEDNESDAY. THE BEST CHANCES FOR SNOW WILL
GENERALLY BE ACROSS NORTHEAST WY AND THE NORTHERN BLACK HILLS AREA.

FOR THE HOLIDAY PERIOD...MODELS CONTINUE TO HAVE A VERY DIFFICULT
TIME SETTLING ON THE FORECAST FROM THANKSGIVING INTO THE HOLIDAY
WEEKEND. THE 00Z GFS HAS GONE BACK TO A WARMER SOLUTION WHILE THE
ECM IS MUCH COLDER. THE ECM IS ALSO SHOWING SNOW LINGERING THROUGH
THE DAY THURSDAY. HAVE ADDED SLIGHT CHANCE POPS TO THE WRN 2/3 OF
THE CWA TO ACCOUNT FOR THIS...BUT WILL NOT ADD ANYMORE POPS PAST 00Z
FRI.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z MONDAY
ISSUED AT 1022 AM MST SUN NOV 23 2014

STRONG NORTHWEST WINDS WILL CONTINUE THROUGH THE AFTERNOON...STRONGEST
ACROSS THE NORTHWEST AND WEST CENTRAL SD PLAINS...WHERE SOME GUSTS
TO NEAR 50 KTS ARE EXPECTED. WINDS WILL GRADUALLY DECREASE AFTER
00Z. ISOLATED TO SCATTERED SHSN/MVFR CIGS ARE MOST LIKELY ACROSS
NORTHWEST SD...THE NORTHERN BLACK HILLS...AND PORTIONS OF
NORTHEAST WY THIS AFTERNOON. LOCALIZED IFR CONDITIONS ARE EXPECTED
WITH UPSLOPE ENHANCED SHSN OVER THE NORTHERN BLACK HILLS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 8 PM MST /9 PM CST/ THIS EVENING FOR SDZ014-
     025-027-032-041-043-044-046-047-049.

     HIGH WIND WARNING UNTIL 8 PM MST THIS EVENING FOR SDZ001-002-012-
     013-026-031-072-073.

WY...NONE.
&&

$$

SHORT TERM...CARPENTER
LONG TERM...13
AVIATION...26






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