722
FXUS63 KUNR 192146
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
246 PM MST THU DEC 19 2024
KEY MESSAGES
- STRONG NORTHWEST WINDS WILL CONTINUE TO DIMINISH THROUGH THIS
EVENING.
- AFTER A COLD DAY TOMORROW ACROSS NORTHWESTERN AND SOUTH CENTRAL
SOUTH DAKOTA, MILD AND MOSTLY DRY CONDITIONS ARE EXPECTED FOR
THE NEXT SEVERAL DAYS.
- THE BEST CHANCE FOR MEASURABLE PRECIPITATION THROUGH CHRISTMAS
EVE LOOKS TO BE WITH A QUICK-MOVING DISTURBANCE ON SUNDAY THAT
COULD BRING A FEW RAIN AND SNOW SHOWERS TO THE AREA.
UPDATE
ISSUED AT 241 PM MST THU DEC 19 2024
WINDS ACROSS WESTERN SD HAVE BEGUN TO DECREASE AS THE CLIPPER
SYSTEM SLIDES TO SOUTHEAST OF THE REGION. THEREFORE, AM LETTING
THE WIND HEADLINES EXPIRE. NORTHWEST WINDS WILL REMAIN BREEZY
THROUGH THE LATE AFTERNOON WITH SOME GUSTS OF 45 MPH OR GREATER.
WINDS WILL CONTINUE TO DIMINISH THROUGH THE EVENING HOURS.
DISCUSSION
(THIS EVENING THROUGH THURSDAY)
ISSUED AT 143 PM MST THU DEC 19 2024
IT'S A BIT WINDY OVER WESTERN SOUTH DAKOTA THIS AFTERNOON. THE
CLIPPER SYSTEM HAS PUSHED TO THE SOUTHEAST, LEAVING 6- 7 MB 3-HR
PRESSURE RISES IN ITS WAKE. JUST OFF THE SURFACE, A REGION OF
STRONG 850-700 MB WINDS (50-70KT) HAS SET UP OVER THE CWA. THIS
HAS SUPPORTED THE STRONG AND GUSTY WINDS IMPACTING WESTERN SD THIS
MORNING AND AFTERNOON. GUSTS HAVE FOR THE MOST PART RANGED FROM
40 TO 50 MPH THOUGH GUSTS HAVE REACHED UP TO 60+ MPH IN SEVERAL
SPOTS ACROSS THE NORTHWESTERN AND WESTERN SD PLAINS DOWN INTO
SOUTH CENTRAL SD. ARCTIC AIRMASS OVER SOUTHERN SK IS ALSO PUSHING
INTO THE NORTHERN PLAINS, WITH A FAIRLY STEEP TEMPERATURE GRADIENT
SETTING UP OVER NORTHWESTERN INTO SOUTH CENTRAL SD. TEMPERATURES
ACROSS NORTHWESTERN SD HAVE PLUMMETED TO THE SINGLE DIGITS WHILE
TEMPERATURES ACROSS SOUTHWESTERN SD INTO NORTHEASTERN WY REMAIN AT
A RELATIVELY TOASTY 40-45 DEGREES. AS THE FRONT PUSHED THROUGH
RAPID CITY, TEMPERATURES AT THE OFFICE DROPPED FROM AROUND 43
DEGREES TO 31 DEGREES (A 12 DEGREE DROP) IN A SPAN OF 30 MINUTES.
WINDS WILL DIMINISH OVER THE REGION AS THE CLIPPER SYSTEM
CONTINUES TO DIVE SOUTHEAST AND HIGH PRESSURE MOVES INTO THE
NORTHERN PLAINS. AS WINDS HAVE BEGUN TO TREND DOWNWARD -- HAVE
OPTED TO NOT EXTEND OUR EXISTING WIND HEADLINES WHICH WILL EXPIRE
AT 21-22Z. THE CORE OF THE COLDEST TEMPERATURES WILL REMAIN TO OUR
NORTHEAST WITH LOWS TONIGHT DROPPING INTO THE SINGLE DIGITS TO
JUST BELOW ZERO ACROSS NORTHWESTERN INTO SOUTH CENTRAL SD AND IN
THE TEENS TO LOW 20S ACROSS NORTHEASTERN WY INTO THE BLACK HILLS.
LOW LEVEL THERMAL RIDGE WILL NOSE BACK INTO SOUTHWESTERN SD AND
NORTHEASTERN WY WITH AFTERNOON HIGHS REACHING INTO THE UPPER 40S
TO 50S. NORTHWESTERN INTO SOUTH CENTRAL SD WILL REMAIN UNDER THE
INFLUENCE OF THE ARCTIC AIRMASS WITH HIGHS IN THE UPPER TEENS TO
20S. WINDS WILL PICK UP AGAIN ACROSS THE WESTERN SD PLAINS AGAIN
FRIDAY AFTERNOON AS LEE-TROUGH DEVELOPS OVER EASTERN CO INTO
SOUTHERN AB AND A TIGHT PRESSURE GRADIENT SETS UP OVER THE WESTERN
HALF OF THE STATE. WHILE WINDS WILL CERTAINLY BE BREEZY, THEY
WON'T BE AS STRONG AS THEY ARE TODAY. THE AFOREMENTIONED LEE
TROUGH AXIS MOVES EAST OF THE AREA LATE TOMORROW INTO EARLY
SATURDAY, WITH FEW SENSIBLE WEATHER IMPACTS ANTICIPATED. UPPER
LEVEL RIDGE BUILDS INTO THE WESTERN US BY SATURDAY WITH LOW LEVEL
SOUTHERLY FLOW BRINGING ABOVE AVERAGE TEMPERATURES INTO THE REGION
(HIGHS SATURDAY AFTERNOON WILL BE IN THE 50S).
SHORTWAVE TROUGH WILL CREST THE RIDGE AND SWING SOUTHWARD INTO
THE NORTHERN PLAINS LATE SATURDAY INTO SUNDAY. AHEAD OF THE TROUGH
Q- VECTOR CONVERGENCE AND BETTER MOISTURE WILL SUPPORT CHANCES
FOR LIGHT PRECIP. RECENT DETERMINISTIC RUNS HAVE PUSHED THE SYSTEM
A LITTLE FURTHER NORTH WHICH WILL KEEP THE BEST CHANCES FOR
MEASURABLE (>0.01") PRECIP OVER NORTHERN SD. LREF PROBABILITIES
HAVEN'T CHANGED TOO MUCH IN THE 12Z RUN, KEEPING ~50%
PROBABILITIES OF 24 HR QPF EXCEEDING 0.01" ALONG THE ND/SD BORDER
WITH PROBABILITIES DROPPING OFF AS YOU GO FURTHER SOUTH. A MORE
PROGRESSIVE UPPER LEVEL PATTERN SETS UP FOR EARLY NEXT WEEK WITH
DETERMINISTIC RUNS DEPICTING SOME KIND OF TROUGH FEATURE MOVING
OVER THE REGION IN THE MONDAY/TUESDAY TIME FRAME FOLLOWED BY
UPPER LEVEL RIDGING FOR CHRISTMAS DAY. THOUGH THE DETERMINISTIC
RUNS DIVERGE ON EXACT TIMING, LOCATION, AND STRENGTH OF THESE
FEATURES. IN GENERAL THOUGH -- TEMPERATURES EARLY NEXT WEEK
(THROUGH CHRISTMAS DAY) WILL BE ABOVE AVERAGE, KEEPING ANY NOTIONS
OF A WHITE CHRISTMAS FIRMLY IN OUR DREAMS.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 1028 AM MST THU DEC 19 2024
STRONG, GUSTY NORTHWEST WINDS WILL CONTINUE THROUGH 22Z OVER MOST
OF WESTERN SD. GUSTS TO 40-55KTS WILL BE COMMON THIS MORNING FROM
K2WX-KRAP/KPHP-KICR. WINDS WILL QUICKLY DIMINISH LATE THIS
AFTERNOON AND EVENING. VFR CONDITIONS ARE EXPECTED THROUGH THE
PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...WONG
DISCUSSION/KEY MESSAGES...WONG
AVIATION...10/SCHULTZ
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