296
FXUS63 KUNR 161716
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1016 AM MST SUN FEB 16 2025
KEY MESSAGES
- RECORD TO NEAR-RECORD COLD TEMPERATURES POSSIBLE FOR MANY AREAS MONDAY
THROUGH WEDNESDAY NIGHT, ESPECIALLY THE SOUTH DAKOTA PLAINS.
ALTHOUGH WINDS WILL BE RELATIVELY LIGHT THROUGH MUCH OF THE
PERIOD, WIND CHILL VALUES WILL FALL TO -20 TO AROUND -40F AT
TIMES ACROSS MUCH OF THE FORECAST AREA DURING THIS TIME.
- A PERIOD OF PROLONGED, LIGHT-TO-MODERATE SNOWFALL IS EXPECTED
THIS EVENING INTO TUESDAY, ESPECIALLY AFFECTING NORTHEASTERN
WYOMING, THE BLACK HILLS, AND SOUTHWESTERN SOUTH DAKOTA.
SNOWFALL AMOUNTS OF 2 TO 6 INCHES, WITH LOCALLY HIGHER AMOUNTS,
WILL BE POSSIBLE IN THESE AREAS OVER THE 2-DAY PERIOD.
- LINGERING LIGHT SNOW WILL COME TO AN END DURING THE MIDWEEK PERIOD.
THEREAFTER, A WARMING TREND WILL TAKE PLACE TOWARD THE END OF
THE WEEK, AND ESPECIALLY NEXT WEEKEND.
UPDATE
ISSUED AT 602 AM MST SUN FEB 16 2025
HAVE UPDATED TO ADD MOSTLY SCATTERED FLURRIES TO THE FORECAST THIS
MORNING FOR MUCH OF NORTHEAST WY AND THE BLACK HILLS AREA. LITTLE
OR NO ACCUMULATION IS EXPECTED THIS MORNING.
DISCUSSION
(TODAY THROUGH SATURDAY)
ISSUED AT 238 AM MST SUN FEB 16 2025
CURRENT SURFACE ANALYSIS SHOWS CANADIAN HIGH PRESSURE OVER
EASTERN MT/WESTERN ND, WITH ARCTIC BOUNDARY ALONG THE LEE OF THE
ROCKIES. UPPER LEVEL ANALYSIS SHOWS LOW OVER CENTRAL MANITOBA,
WITH LARGE TROUGH COVERING MUCH OF THE ROCKIES, PLAINS, AND
WESTERN GREAT LAKES. SHORTWAVE RIDGE IS LOCATED ALONG THE WEST
COAST. SKIES ARE CLEAR TO MOSTLY CLOUDY, WITH THE MOST CLOUDS FROM
NORTHEAST WY TO SOUTHWEST SD. A FEW LIGHT SNOW SHOWERS OR
FLURRIES COULD BE REACHING INTO FAR WESTERN PARTS OF NORTHEAST WY
EARLY THIS MORNING. TEMPS RANGE FROM THE SINGLE DIGITS OVER MUCH
OF NORTHEAST WY TO THE TEENS BELOW ZERO OVER PORTIONS OF NORTHWEST
INTO CENTRAL SD. WIND CHILL VALUES MOSTLY RANGE FROM THE SINGLE
DIGITS BELOW TO NEAR 30 BELOW ZERO, LOWEST ACROSS FAR NORTHWEST
SD. WINDS ARE MOSTLY LIGHT FROM THE WEST TO NORTHWEST.
TODAY WILL BE A MAINLY DRY BUT COLD DAY, AS MAIN ENERGY STAYS WEST
OF THE AREA FOR NOW. HIGHS WILL RANGE FROM MOSTLY SINGLE DIGITS
NORTH AND EAST OF THE BLACK HILLS, TO THE MID TO UPPER TEENS ACROSS
SOUTHERN PARTS OF NORTHEAST WY TO FAR SOUTHWEST SD. SKIES WILL BE
VARIABLY CLOUDY IN THE MORNING, BECOMING MOSTLY CLOUDY DURING THE
AFTERNOON. A REINFORCING SHOT OF COLDER ARCTIC AIR STARTS TO SLOWLY
SINK SOUTH ACROSS THE AREA TONIGHT AND MONDAY, THEN LINGERS THROUGH
MIDWEEK. TEMPS ARE EXPECTED TO STAY MAINLY BELOW ZERO FOR AN
EXTENDED PERIOD ACROSS MOST AREAS NORTH AND EAST OF THE BLACK HILLS
FROM TONIGHT THROUGH AT LEAST WEDNESDAY MORNING AND LIKELY INTO
THURSDAY FOR SOME AREAS. THE COLDEST AIR IS EXPECTED TO BE MOSTLY IN
THE MONDAY NIGHT TO WEDNESDAY TIMEFRAME. AS FAR AS COLD WEATHER
HEADLINES ARE CONCERNED, HAVE UPGRADED THE EXTREME COLD WATCH TO A
WARNING ACROSS FAR NORTHWEST SD FOR TONIGHT THROUGH WEDNESDAY. HAVE
DECIDED TO ISSUE A COLD WEATHER ADVISORY FOR THE REST OF NORTHWEST
INTO WEST CENTRAL AND SOUTH CENTRAL SD FOR LATER TONIGHT INTO MONDAY
MORNING. ADDITIONAL COLD WEATHER HEADLINES THROUGH THE FIRST HALF OF
THE WEEK MAY BE ISSUED MORE ON A DAY TO DAY BASIS RIGHT NOW WITH
SOME VARIABILITY IN WIND CHILL VALUES THROUGH THE PERIOD.
BEYOND THE BITTER COLD TEMPS FOR THE NEXT SEVERAL DAYS, SOME
SNOWFALL CAN BE EXPECTED OVER THE NEXT FEW DAYS AS WELL. THE MOST
IMPACTFUL SNOWFALL LOOKS TO BE ACROSS SOUTHERN PORTIONS OF NORTHEAST
WY TO SOUTHWEST SD FROM TONIGHT INTO TUESDAY, AS A SERIES OF WEAK
DISTURBANCES ALOFT IN NORTHWESTERLY FLOW INTERACT WITH TIGHTER
BAROCLINIC ZONE IN PLACE ACROSS THIS REGION. MOST OF THE SNOWFALL IS
LIKELY TO BE LIGHT, BUT FOR A PROLONGED PERIOD OF TIME. A PERIOD OR
TWO OF MORE ENHANCED HEAVIER SNOWFALL WILL LIKELY DEVELOP ACROSS AT
LEAST FAR SOUTHWEST SD, ESPECIALLY LATER TONIGHT INTO MONDAY NIGHT.
LREF CHANCES FOR 3 INCHES OR MORE OF SNOWFALL ARE HIGHEST FROM THE
NEWCASTLE AREA INTO FAR SOUTHWEST SD, 50 TO 90 PERCENT, WITH CHANCES
TAPERING OFF RATHER SHARPLY OUTSIDE THESE AREAS. HAVE DECIDED TO
ISSUE A WINTER WEATHER ADVISORY FOR PORTIONS OF NORTHEAST WY AND
MUCH OF SOUTHWEST SD FOR 2 TO 6 INCHES OF SNOW FROM SUNDAY NIGHT
THROUGH EARLY TUESDAY. HIGHEST AMOUNTS SHOULD GENERALLY BE ACROSS
FAR SOUTHWEST SD.
BITTER COLD TEMPS WILL LINGER MIDWEEK. THE COLDEST AIR WILL BEGIN TO
SCOUR OUT OF THE AREA ON THURSDAY, ESPECIALLY THE HIGHER ELEVATIONS
OF THE FORECAST AREA. WILL START TO SEE REAL IMPROVEMENT FRIDAY AND
ESPECIALLY OVER THE WEEKEND. HIGHS WILL LIKELY BE BACK ABOVE AVERAGE
IN MANY AREAS FOR THE WEEKEND, WITH SOME 50S POSSIBLE BY SUNDAY.
THERE WILL BE SOME LINGERING CHANCES FOR LIGHT SNOW AND FLURRIES
MIDWEEK, BUT A MAINLY DRY PATTERN SHOULD DEVELOP FOR THE END OF THE
WEEK AND THE WEEKEND.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1014 AM MST SUN FEB 16 2025
VFR CONDITIONS FORECAST THROUGH THE AFTERNOON INTO EARLY EVENING
HOURS. A SYSTEM WILL MOVE INTO THE REGION TONIGHT, WITH A
PROLONGED PERIOD OF LIGHT SNOW BEGINNING FROM NORTHEAST WY INTO
WESTERN SD THROUGH MONDAY. EXPECT IFR TO LOCAL LIFR CONDS IN
LIGHT SNOW AND LOW CLOUDS; EXPECTED DEVELOPMENT AFTER 01-03Z
TONIGHT AND WILL PERSIST THROUGH THE FORECAST PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...EXTREME COLD WARNING FROM 8 PM THIS EVENING TO 11 AM MST
WEDNESDAY FOR SDZ001-002-014-078.
COLD WEATHER ADVISORY FROM 11 PM MST /MIDNIGHT CST/ THIS EVENING
TO 11 AM MST /NOON CST/ MONDAY FOR SDZ012-013-025-031-032-
043-046-047-049-072-073-077.
WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 AM MST
TUESDAY FOR SDZ026-028-030-042-044-074.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 5 AM MST
TUESDAY FOR SDZ027-029-041-075-076.
WY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 5 AM MST
TUESDAY FOR WYZ058-059.
UPDATE...26
DISCUSSION/KEY MESSAGES...26
AVIATION...SE
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