077
FXUS63 KUNR 170843
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
143 AM MST FRI JAN 17 2025
KEY MESSAGES
-STRONG COLD FRONT ARRIVES TODAY WITH GUSTY NORTHWEST WINDS AND
FALLING TEMPERATURES
-A BIT OF LIGHT SNOW/FLURRIES ON THE PLAINS WITH A FEW INCHES OF
ACCUMULATION IN THE NORTHERN BLACK HILLS THROUGH SATURDAY.
HEAVIER SNOW SHOWERS POSSIBLE TODAY IN THE WEST WITH
SIGNIFICANTLY REDUCED VISIBITLIES AT TIMES
-ARCTIC FRONT WILL BRING BITTERLY COLD TEMPERATURES OVER THE
WEEKEND INTO EARLY NEXT WEEK
DISCUSSION
(TODAY THROUGH THURSDAY)
ISSUED AT 121 AM MST FRI JAN 17 2025
WATER VAPOR SHOWS UPPER LOW OVER SOUTHERN SASK/MANITOBA WITH TROF
CARVING OUT OVER THE NORTHWEST CONUS. AT THE SURFACE, PAC COLD
FRONT ALREADY PUSHING THROUGH OUR NORTHWESTERN ZONES WITH ARCTIC
FRONT JUST NORTH OF THE US/CNDN BORDER. EARLY MORNING TEMPS
LARGELY IN THE 30S WITH DOWNSLOPE FLOW CONTINUING.
NORTHWEST WINDS WILL INCREASE QUICKLY THIS MORNING WITH 3-4MB/3HR
PRESSURE RISES AND COLD ADVECTION BEHIND THE PACIFIC FRONT,
FURTHER REINFORCED BY THE ARCTIC FRONT THIS AFTERNOON. CURRENT
WIND ADVISORY LOOKS GOOD. HIGHS WILL BE EARLY THIS MORNING, WITH
FALLING TEMPS THROUGH THE DAY, ESPECIALLY ONCE THE ARCTIC BOUNDARY
MOVES IN. LIGHT SNOW WILL SPREAD INTO OUR WESTERN THIRD TO HALF
OF ZONES BY MID TO LATE MORNING. SOME HEAVIER SNOW SHOWERS NOT OUT
OF THE QUESTION GIVEN STEEP LOW LEVEL RATES. COMBINED WITH THE
WINDS, VISIBILITIES COULD BECOME PROBLEMATIC IN ANY HEAVIER SNOW
SHOWERS.
REINFORCING SHOT OF ARCTIC AIR ARRIVES ON SATURDAY ALONG WITH SOME
ADDITIONAL LIGHT SNOW, AGAIN MOSTLY IN OUR WESTERN THIRD TO HALF
OF ZONES. A FEW INCHES LIKELY IN UPSLOPE AREAS OF THE NORTHERN
BLACK HILLS, AND MAYBE AN INCH OR SO IN NORTHEAST WY.
PROBABILITIES FOR MUCH, IF ANY, SNOW ACCUMULATION ON THE SD PLAINS
VERY LOW.
DRIER CONDITIONS ARE THEN EXPECTED BY SUNDAY AS HIGH PRESSURE
BUILDS IN FROM THE NORTH. BITTERLY COLD CONDITIONS ARE LIKELY
THROUGH MONDAY INTO MONDAY NIGHT AS 1050MB HIGHS SETTLES IN. COLD
WEATHER ADVISORIES (GENERALLY -25F AND COLDER) ARE LIKELY TO BE
NEEDED BEGINNING LATE SATURDAY, AND POSSIBLE EXTREME COLD WARNINGS
(GENERALLY -35F AND COLDER) FOR SUNDAY NIGHT AND MONDAY AS CORE
OF COLDEST AIR MOVES IN.
WARM ADVECTION WILL QUICKLY RETURN MONDAY NIGHT INTO TUESDAY AS
NEXT CLIPPER APPROACHES AND PUSHES THE ARCTIC AIR EAST OF THE
AREA. ACTIVE NORTHWEST FLOW LOOKS TO DEVELOP AFTERWARD WITH
HIGHLY VARIABLE TEMPS AND INCREASED WIND. CONFIDENCE IN TEMPS AND
WEATHER DROP OFF SHARPLY TOWARD THE END OF NEXT WEEK DUE TO HIGH
VARIABILITY IN MODEL SOLUTIONS.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1013 PM MST THU JAN 16 2025
VFR CONDITIONS ARE EXPECTED THROUGH TODAY AND TONIGHT. EARLY
FRIDAY MORNING (AFTER 05-07Z), AN ARCTIC COLD FRONT WILL BEGIN TO
SLIDE THROUGH THE REGION. CEILING/VISIBILITY WILL BECOME MVFR/IFR
ACROSS NORTHEASTERN WY FRIDAY MORNING AS LOW CLOUDS SAG INTO THE
AREA. SNOW SHOWERS ARE EXPECTED TO ACCOMPANY THE FRONT, BUT
CONFIDENCE IN TIMING/DURATION IS LOW AT THIS TIME. HIGHEST
PROBABILITY FOR MVFR/IFR CONDITIONS IN THE BLACK HILLS.
NORTHWESTERLY WINDS WILL INCREASE TO 20 TO 30 MPH WITH GUSTS UP TO
50 MPH, ESPECIALLY OVER THE WESTERN SD PLAINS, AFTER 16-18Z FRIDAY
MORNING. BEFORE THESE STRONG WINDS REACH THE SURFACE, THERE COULD
BE SOME LLWS OVER PARTS OF THE AREA TONIGHT.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WIND ADVISORY FROM 8 AM MST /9 AM CST/ THIS MORNING TO 5 PM MST
/6 PM CST/ THIS AFTERNOON FOR SDZ001-002-012>014-026-
030>032-042>044-046-047-049-072-073-077-078.
WY...NONE.
DISCUSSION/KEY MESSAGES...JOHNSON
AVIATION...SE
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