465
FXUS63 KUNR 161647
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
947 AM MST THU JAN 16 2025
KEY MESSAGES
-MILD TODAY, THEN TURNING COLDER FRIDAY WITH STRONG NORTHWEST
WINDS
-ARCTIC AIR ARRIVES BY FRIDAY NIGHT WITH BITTERLY COLD
TEMPERATURES OVER THE WEEKEND INTO EARLY NEXT WEEK
-A BIT OF LIGHT SNOW/FLURRIES ON THE PLAINS WITH A FEW INCHES
ACCUMULATION IN THE NORTHERN BLACK HILLS FRIDAY THROUGH SATURDAY
DISCUSSION
(TODAY THROUGH WEDNESDAY)
ISSUED AT 111 AM MST THU JAN 16 2025
WATER VAPOR SHOWS RATHER FLAT UPPER RIDGE IN THE NORTHWEST FLOW OVER
THE NORTHERN ROCKIES/NORTHERN PLAINS WITH NEXT UPSTREAM TROF OVER
BC. AT THE SURFACE, INVERTED SURFACE RIDGE IS PUSHING INTO THE
WESTERN DAKOTAS WITH LEE TROF DEEPENING TO OUR WEST. VERY MILD
EARLY THIS MORNING WITH MANY AREAS IN THE 30S UNDER WESTERLY
DOWNSLOPE FLOW.
VERY MILD TEMPS EXPECTED TODAY WITH LEE TROF ADVANCING INTO THE
DAKOTAS AND THERMAL RIDGE PEAKING OVERHEAD. NBM APPEARS WAY
UNDERDONE WITH HIGHS AND HAVE RAISED TEMPS TO NEAR MOS AVERAGES.
WOULDN'T BE SURPRISED TO SEE A COUPLE LOCATIONS AROUND 60F ALONG
THE EASTERN SLOPES OF THE BLACK HILLS. CONTINUED DOWNSLOPE FLOW
AND RELATIVELY MILD TEMPS EXPECTED TONIGHT.
AFOREMENTIONED UPPER TROF OVER BC WILL CARVE THROUGH THE NORTHERN
ROCKIES/NORTHERN PLAINS FRIDAY. PACIFIC FRONT MOVES THROUGH VERY
EARLY IN THE DAY FOLLOWED BY THE ARCTIC FRONT FRIDAY
AFTERNOON/EVENING. LIGHT SNOW WILL ACCOMPANY THE FRONTS, BUT
MOISTURE SHOULD REMAIN LIMITED, WITH THE EXCEPTION OF SOME UPSLOPE
IN THE NORTHERN BLACK HILLS. WINDS ARE LIKELY TO EXCEED WIND
ADVISORY CRITERIA ON THE WESTERN SD PLAINS DURING THE DAY FRIDAY,
SO BE ON THE LOOKOUT FOR HEADLINES EITHER THIS AFTERNOON OR
TONIGHT.
SECONDARY TROF MOVES THROUGH SATURDAY WITH A REINFORCING SHOT OF
ARCTIC AIR. ADDITIONAL LIGHT SNOW/FLURRIES AGAIN LIKELY,
ESPECIALLY FOR THE NORTHERN BLACK HILLS. WITH GUSTY NORTHWEST
WINDS CONTINUING INTO SATURDAY NIGHT, WE'LL LIKELY BEGIN TO GET
INTO COLD WEATHER ADVISORY RANGE (GENERALLY -25F AND COLDER).
BITTERLY COLD AIR WILL CONTINUE SUNDAY INTO TUESDAY MORNING AS
1050+MB SURFACE HIGH BUILDS SLOWLY SOUTH INTO THE NORTHERN
PLAINS. WIDESPREAD COLD WEATHER ADVISORY CRITERIA LIKELY TO
CONTINUE, AND POSSIBLY INTO EXTREME COLD WARNING RANGE (GENERALLY
-35F AND COLDER) ON MONDAY. ECMWF EFI IS SUGGESTING TOWARDS THE
LOWER END OF CLIMATOLOGY FOR MONDAY.
PACIFIC AIR LOOKS TO RUSH BACK IN ON TUESDAY WITH HIGHS FOR MID
WEEK NEAR CLIMATOLOGICAL AVERAGES, ALONG WITH INCREASING CHANCES
FOR LIGHT SNOW.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY)
ISSUED AT 942 AM MST THU JAN 16 2025
VFR CONDITIONS ARE EXPECTED THROUGH TODAY AND TONIGHT. EARLY
FRIDAY MORNING, 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 AND LIGHT SNOW MOVE
INTO THE AREA.
NORTHWESTERLY WINDS WILL INCREASE TO 20 TO 30 MPH WITH GUSTS UP TO
50 MPH, ESPECIALLY OVER THE WESTERN SD PLAINS, ON FRIDAY MORNING.
BEFORE THESE STRONG WINDS REACH THE SURFACE, THERE COULD BE SOME
LLWS OVER PARTS OF THE AREA LATE TONIGHT.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...JOHNSON
AVIATION...POJORLIE
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