592
FXUS63 KUNR 150955
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
255 AM MST SUN DEC 15 2024
KEY MESSAGES
- UPPER LEVEL TROUGH WILL CONTINUE TO BRING GOOD CHANCES FOR LIGHT RAIN,
LIGHT FREEZING RAIN, AND SNOW TODAY INTO THIS EVENING FROM
NORTHEAST WY TO THE NORTHERN BLACK HILLS AND NORTHWEST SD, WITH
A TRAILING COOL FRONT BRINGING GUSTY WEST TO NORTHWEST WINDS
LATER TODAY INTO MONDAY.
- A WEAK DISTURBANCE WILL BRING CHANCES FOR LIGHT SNOW LATE MONDAY NIGHT
INTO TUESDAY. OTHERWISE, MOSTLY DRY CONDITIONS ARE EXPECTED
THROUGH THE WEEK, WITH TEMPERATURES NEAR TO ABOVE AVERAGE.
DISCUSSION
(TODAY THROUGH SATURDAY)
ISSUED AT 255 AM MST SUN DEC 15 2024
CURRENT SURFACE ANALYSIS SHOWS WHAT IS LEFT OF THE ARCTIC
BOUNDARY IS LOCATED ACROSS FAR EASTERN MT, THE BLACK HILLS AREA,
AND WESTERN NE. A PACIFIC COLD FRONT IS MOVING QUICKLY ACROSS THE
ROCKIES. UPPER LEVEL ANALYSIS SHOWS TROUGH OVER THE PACIFIC NW
INTO THE ROCKIES, WITH INCREASING SOUTHWESTERLY FLOW ACROSS THE
NORTHERN PLAINS. INITIAL DISTURBANCE HAS BEEN MOVING ACROSS THE
AREA DURING THE LATE EVENING AND OVERNIGHT HOURS WITH A FEW AREAS
OF LIGHT RAIN ACROSS NORTHEAST WY AND THE BLACK HILLS, AND SOME
LIGHT FREEZING RAIN FROM FAR NORTHEAST WY TO NORTHWEST SD. TEMPS
RANGE FROM THE 30S AND LOWER 40S ACROSS NORTHEAST WY, THE BLACK
HILLS, AND FAR SOUTHWEST SD TO THE UPPER TEENS AND 20S OVER MUCH
OF THE SD PLAINS. WEST TO SOUTHWEST WINDS HAVE INCREASED ACROSS A
GOOD PORTION OF NORTHEAST WY AND PARTS OF THE BLACK HILLS.
PCPN WITH THE INITIAL WAVE IS MOVING NORTHEAST OUT OF NORTHWEST SD
AND DISSIPATING. THE NEXT WAVE SHOULD THEN MOVE QUICKLY INTO
NORTHWESTERN/WESTERN PORTIONS OF THE CWA AROUND OR AFTER 12Z. SOME
AREAS OF LIGHT RAIN, SNOW, AND LIGHT FREEZING RAIN WILL DEVELOP
ACROSS FAR NORTHEAST WY INTO THE NORTHERN BLACK HILLS AND NORTHWEST
SD THROUGH THE MORNING HOURS. FREEZING RAIN POTENTIAL SHOULD MOSTLY
BE LIMITED TO EXTREME NORTHEAST WY AND NORTHWEST SD THIS MORNING.
HAVE EXTENDED THE WINTER WX ADVISORY TO COVER MUCH OF MEADE COUNTY
WITH THE POTENTIAL FOR LIGHT FREEZING RAIN LATER THIS MORNING. THE
PACIFIC COLD FRONT MOVING ACROSS THE FORECAST AREA DURING THE DAY
WILL BRING INCREASING WEST TO NORTHWEST WINDS AND COLDER AIR ALOFT
TO HELP SWITCH MIXED PCPN OVER TO MAINLY SNOW ACROSS NORTHEAST WY
AND THE BLACK HILLS BY THE AFTERNOON, AND EVENTUALLY ACROSS
NORTHWEST SD LATER TODAY. SNOWFALL POTENTIAL CONTINUES TO TREND
DOWNWARD FOR MOST AREAS, WITH MOSTLY 1 TO 3 INCHES IN THE FORECAST
ACROSS THE NORTHERN BLACK HILLS/BEAR LODGE MTS THIS AFTERNOON AND
EVENING, AN INCH OR LESS ELSEWHERE FROM FAR NORTHEAST WY INTO
NORTHWEST SD. PRECIPITATION WILL TAPER OFF THIS EVENING INTO THE
OVERNIGHT. FURTHER TO THE SOUTH AND EAST ACROSS THE FORECAST AREA,
LITTLE OR NO PCPN IS EXPECTED WITH THIS SYSTEM. WILL KEEP WIND
ADVISORY FOR EXTREME SOUTHWEST SD TODAY, AS WESTERLY WINDS GUST TO
40 TO 50 MPH. WINDS LOOK TO BE NEAR LOW END ADVISORY CRITERIA ACROSS
SOME OF THE SD PLAINS TONIGHT, ESPECIALLY NORTHWEST INTO WEST
CENTRAL SD. WILL LET LATER SHIFTS DETERMINE IF AN ADVISORY WILL BE
NEEDED. WINDS SHOULD TAPER OFF INTO MONDAY AS THE UPPER TROUGH MOVES
NORTHEAST AWAY FROM THE REGION.
THE UPCOMING WEEK LOOKS TO BE MOSTLY DRY WITH NEAR TO ABOVE AVERAGE
TEMPERATURES ON MOST DAYS. ANOTHER SHORTWAVE TROUGH MOVES QUICKLY
ACROSS THE AREA LATE MONDAY NIGHT AND TUESDAY. THIS ONE WILL BE
WEAKER, WITH SOME CHANCES FOR LIGHT SNOW ACROSS MUCH OF THE AREA.
ANY ACCUMULATIONS LOOK TO BE MINOR, WITH CHANCES FOR AN INCH OR MORE
AT LESS THAN 20 PERCENT ACROSS THE AREA. THE WARMEST CONDITIONS OF
THE WORK WEEK ARE EXPECTED TO BE TOWARD THE LATTER PART OF THE WEEK,
THURSDAY AND FRIDAY, WITH HIGHS IN THE 30S AND 40S.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1038 PM MST SAT DEC 14 2024
MVFR TO LOCALIZED LIFR CONDITIONS IN LOW STRATUS AND BR/FG WILL
CONTINUE FROM FAR SOUTH CENTRAL SD THROUGH PORTIONS OF
NORTHWESTERN SD UNTIL AROUND 12Z. AFTER 12Z, AREAS OF MVFR/IFR
CIGS AND POTENTIALLY VSBYS WILL ACCOMPANY DEVELOPING RA/SN ACROSS
NORTHEASTERN WY, WITH THIS ACTIVITY SHIFTING INTO NORTHWESTERN SD
THRU THE MORNING AND INTO THE AFTERNOON.
STRONG WEST/SOUTHWEST WINDS AND GUSTS OVER PORTIONS OF THE REGION
WILL TRANSITION TO NORTHWEST WINDS BEHIND A COLD FRONT AFTER 18Z.
SOME GUSTS 40-50 KT CANNOT BE RULED OUT, PARTICULARLY ACROSS THE
NORTHEASTERN WY PLAINS, NORTHWESTERN SD, AND FAR SOUTHWESTERN SD.
FROM NOW THROUGH 12Z, LOW-LEVEL WIND SHEAR WILL BE POSSIBLE OVER
MUCH OF THE SOUTHERN HALF OF THE AREA, INCLUDING AT KRAP, AS 40-55
KT FLOW DEVELOPS IN THE 2-4 KFT ABOVE GROUND LAYER.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR SDZ001-
002-012-013-073-078.
WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR SDZ041.
WY...WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR WYZ056-
060.
DISCUSSION/KEY MESSAGES...26
AVIATION...SHERBURN
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