375
FXUS63 KUNR 180952
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
252 AM MST TUE FEB 18 2025
KEY MESSAGES
- BITTER COLD TEMPERATURES ACROSS THE AREA THROUGH THURSDAY
MORNING, ESPECIALLY THE SOUTH DAKOTA PLAINS. ALTHOUGH WINDS WILL
BE RELATIVELY LIGHT THROUGH MUCH OF THE PERIOD, WIND CHILL
VALUES WILL FALL TO -20 TO NEAR -45F AT TIMES ACROSS MUCH OF THE
FORECAST AREA, ESPECIALLY OVERNIGHT INTO THE MORNING HOURS.
- LIGHT SNOWFALL WILL CONTINUE TODAY, ESPECIALLY AFFECTING NORTHEASTERN
WYOMING, THE BLACK HILLS, AND SOUTHWESTERN INTO SOUTH CENTRAL
SOUTH DAKOTA. ADDITIONAL SNOWFALL OF UP TO AN INCH OR SO CAN BE
EXPECTED ACROSS THESE AREAS.
- A WARMING TREND WILL TAKE PLACE TOWARD THE END OF THE WEEK, AND
ESPECIALLY THE WEEKEND, WITH ABOVE AVERAGE TEMPERATURES OVER
THE WEEKEND INTO NEXT WEEK.
DISCUSSION
(TODAY THROUGH MONDAY)
ISSUED AT 252 AM MST TUE FEB 18 2025
CURRENT SURFACE ANALYSIS SHOWS ARCTIC FRONT REMAINING MOSTLY
ACROSS THE LEE OF THE ROCKIES, WITH THE SURFACE HIGH CREEPING
SOUTH ACROSS SK AND APPROACHING FAR NORTHEAST MT/NORTHERN ND.
UPPER LEVEL ANALYSIS SHOWS LOW PRESSURE NEAR THE NORTHERN GREAT
LAKES, WITH TROUGH EXTENDING WESTWARD ACROSS PORTIONS OF THE UPPER
MIDWEST INTO SOUTH CENTRAL CANADA. FAST NORTHWEST FLOW ALOFT
ACROSS OUR REGION CONTINUES TO BRING WEAK ENERGY ACROSS THE AREA,
HELPING TO PRODUCE LIGHT SNOW AND FLURRIES ACROSS A GOOD PORTION
OF NORTHEAST WY, THE BLACK HILLS AREA, AND SOUTHWEST SD. WATER
VAPOR IMAGERY SHOWS A LITTLE STRONGER DISTURBANCE APPROACHING FROM
SOUTHEAST MT, SO SNOW COVERAGE AND INTENSITY SHOULD INCREASE SOME
OVER THE NEXT FEW HOURS. BITTER COLD TEMPS IN PLACE ACROSS THE
REGION, WITH TEMPS ACROSS OUR AREA RANGING FROM THE SINGLE DIGITS
BELOW ZERO ACROSS NORTHEAST WY TO NEAR 30 BELOW ACROSS A FEW AREAS
OF FAR NORTHWEST SD WHERE SKIES ARE MOSTLY CLEAR. EAST TO
SOUTHEAST WINDS ARE GUSTING TO 10 TO 15 MPH IN SOME AREAS,
PRODUCING WIND CHILLS FROM 20 BELOW TO 45 BELOW, LOWEST OVER
NORTHWEST SD.
THE FRIGID AIRMASS ACROSS THE CENTRAL US WILL PERSIST THROUGH THE
MIDWEEK PERIOD, WITH SIGNIFICANT IMPROVEMENT NOT COMING UNTIL LATER
ON THURSDAY AND ESPECIALLY TOWARD THE END OF THE WEEK. FOR TODAY,
CONDITIONS WILL IMPROVE A BIT THROUGH THE DAYTIME HOURS, BUT TEMPS
WILL REMAIN BELOW ZERO ACROSS MOST OF WESTERN SD AND POINTS FURTHER
EAST. HIGHS WILL LIKELY EDGE INTO THE SINGLE DIGITS ABOVE ZERO OVER
AT LEAST PORTIONS OF NORTHEAST WY. WIND CHILL VALUES WILL STAY BELOW
ZERO, AND WELL BELOW ZERO FROM NORTHWEST INTO CENTRAL SD. AS ARCTIC
HIGH SLIDES INTO THE NORTHERN PLAINS LATE TODAY AND TONIGHT, WINDS
WILL BECOME VERY LIGHT AND CLOUD COVERAGE WILL GRADUALLY DECREASE
FROM NORTH TO SOUTH. TEMPS WILL LIKELY BE COLDEST TONIGHT IN MOST
AREAS. LOWS WILL DROP TO THE TEENS AND 20S BELOW ZERO, WITH SOME
-30S LIKELY IN USUAL COLDER SPOTS ACROSS NORTHWEST SD. EXTREME
COLD WARNINGS AND COLD ADVISORIES WILL BE ISSUED AGAIN LATER TODAY
FOR TONIGHT INTO WEDNESDAY MORNING ACROSS MUCH OF THE AREA.
WEDNESDAY NIGHT LOWS WILL LIKELY BE A LITTLE HIGHER THAN TONIGHT,
ESPECIALLY ACROSS NORTHEAST WY AND THE BLACK HILLS, AS THE HIGH
STARTS TO MOVE EAST OF THE AREA. HOWEVER, WINDS WILL START TO
INCREASE A BIT AND WIND CHILL VALUES COULD ACTUALLY BE A BIT LOWER,
ESPECIALLY TOWARD CENTRAL SD.
AS FAR AS THE LINGERING SNOWFALL IS CONCERNED, ADDITIONAL LIGHT SNOW
WILL CONTINUE THIS MORNING, AND START TO SPREAD A LITTLE FURTHER
EAST ACROSS PORTIONS OF NORTHWEST INTO SOUTH CENTRAL SD.
PROBABILITIES FOR AN ADDITIONAL INCH OR MORE OF SNOWFALL TODAY ARE
HIGHEST FROM THE BLACK HILLS TO SOUTHWEST AND MUCH OF SOUTH CENTRAL
SD (40 TO OVER 80 PERCENT) AS THE NEXT DISTURBANCE MOVES ACROSS THIS
MORNING AND EARLY AFTERNOON. MOST AREAS FROM NORTHEAST WY TO SOUTH
CENTRAL SD WILL SEE UP TO AN INCH OR POSSIBLY TWO INCHES OF
ADDITIONAL ACCUMULATION TODAY. CONDITIONS WILL FINALLY START TO
IMPROVE FROM NORTHWEST TO SOUTHEAST THIS AFTERNOON AND EVENING AS
THE SURFACE HIGH APPROACHES FROM THE NORTH.
WARMING TREND IS STILL ON SCHEDULE FOR LATE THIS WEEK, AND
ESPECIALLY BY THE WEEKEND. A STORM SYSTEM, OFF THE WEST COAST NOW,
WILL SLIDE SOUTHWEST AND SOUTH OF OUR AREA LATE WEEK. THIS WILL
ALLOW A DEVELOPING RIDGE BEHIND IT TO MOVE ACROSS THE WESTERN US AND
EVENTUALLY OVER THE PLAINS LATER THIS WEEKEND AND EARLY NEXT WEEK.
TEMPERATURES MAY BE A BIT SLOWER TO REBOUND LATE WEEK WITH SNOW
COVER IN PLACE, BUT SHOULD BE ABOVE AVERAGE IN MOST AREAS BY
SATURDAY. HIGHS IN THE 50S, AND EVEN SOME 60S, LOOK LIKELY IN MOST
AREAS BY EARLY NEXT WEEK.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 951 PM MST MON FEB 17 2025
WIDESPREAD MVFR/AREAS IFR CONDITIONS DUE TO LIGHT SNOW/LOW STRATUS
WILL CONTINUE THROUGH THE DAY ON TUESDAY, WITH GRADUAL IMPROVEMENT
EXPECTED TUESDAY EVENING. PERIODIC LIFR CONDITIONS MAY OCCUR,
ESPECIALLY IN/NEAR THE BLACK HILLS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...EXTREME COLD WARNING UNTIL 11 AM MST WEDNESDAY FOR SDZ001-002-
014-078.
EXTREME COLD WARNING UNTIL 11 AM MST /NOON CST/ THIS MORNING FOR
SDZ012-013-025-031-032-043-046-047-049-072-073-077.
COLD WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR SDZ024-
026>030-041-042-044-074>076.
WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR
SDZ026>030-041-042-044-074>076.
WY...EXTREME COLD WARNING UNTIL 11 AM MST THIS MORNING FOR WYZ060.
COLD WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR
WYZ054>059.
WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR WYZ058-
059.
DISCUSSION/KEY MESSAGES...26
AVIATION...10
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