270
FXUS63 KUNR 151705
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1005 AM MST WED JAN 15 2025
KEY MESSAGES
- WARMER TODAY AND THURSDAY
- ARCTIC AIR ARRIVES FRIDAY WITH VERY COLD/BITTERLY COLD
TEMPERATURES OVER THE WEEKEND INTO EARLY NEXT WEEK. A BIT OF
LIGHT SNOW ON THE PLAINS WITH A FEW INCHES ACCUMULATION IN THE
NORTHERN BLACK HILLS
DISCUSSION
(TODAY THROUGH TUESDAY)
ISSUED AT 1246 AM MST WED JAN 15 2025
WATER VAPOR SHOWS UPPER HIGH JUST OFFSHORE THE WEST COAST WITH
RIDGE EXTENDING EAST-NORTHEAST THROUGH THE NORTHERN ROCKIES INTO
THE NORTHERN PLAINS. AT THE SURFACE, BROAD TROF EXTENDS ACROSS THE
NORTHERN PLAINS.
DRY AND MILD TEMPS EXPECTED THROUGH THURSDAY WITH RELATIVELY FLAT
UPPER RIDGE OVERHEAD AND SOUTHWEST/WEST BOUNDARY LAYER FLOW.
WARMEST DAY WILL BE THURSDAY WITH TEMPS INTO THE 50S
EAST/SOUTHEAST OF THE BLACK HILLS (DOWNSLOPE FLOW).
NEXT UPPER TROF DIVES SOUTHEAST FROM CANADA INTO THE NORTHERN
PLAINS ON FRIDAY. ARCTIC FRONT PUSHES THROUGH EARLY IN THE DAY
WITH LIGHT SNOW DEVELOPING. MOISTURE LOOKS FAIRLY LIMITED, BUT
MAYBE A COUPLE INCHES IN THE NORTHERN BLACK HILLS. SECONDARY
ARCTIC BOUNDARY MOVES THROUGH ON SATURDAY, WITH A BIT MORE SNOW
POSSIBLE. BAROCLINIC ZONE SHOULD PUSH FAR ENOUGH TO OUR SOUTHWEST
SUNDAY AND MONDAY WITH LESS CHANCES FOR ANY APPRECIABLE SNOW.
TEMPS WILL GET PROGRESSIVELY COLDER THROUGH THE WEEKEND INTO EARLY
NEXT WEEK AS LONG WAVE TROF CONTINUES TO DIG ACROSS THE CONUS.
1050-1060MB SURFACE HIGH FINALLY BUILDS INTO THE NORTHERN
ROCKIES/NORTHERN PLAINS REGION MONDAY AND EARLY TUESDAY. TEMPS
WILL LIKELY PLUNGE WELL BELOW ZERO AT NIGHT, AND STRUGGLE TO EVEN
GET ABOVE ZERO DURING THE DAY, WITH THE MOST FRIGID TEMPS LIKELY
TO BE IN THE SUNDAY MORNING THROUGH TUESDAY MORNING TIME FRAME.
WHILE THIS WILL LIKELY NOT BE A WIDESPREAD RECORD BREAKING COLD
OUTBREAK, THE ECMWF EFI DOES SUGGEST THIS TO BE SIGNIFICANT, AND
THE CURRENT FORECAST TEMPS MAY NOT BE LOW ENOUGH. BE ON THE
LOOKOUT FOR POSSIBLE COLD/EXTREME COLD HEADLINES AS WE APPROACH
THE EVENT.
WARMER AIR SHOULD QUICKLY MOVE BACK INTO THE REGION BY THE MIDDLE
OF NEXT WEEK.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1003 AM MST WED JAN 15 2025
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. NORTHWEST
WINDS WILL BE BREEZY ACROSS THE SD PLAINS THIS AFTERNOON.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...JOHNSON
AVIATION...POJORLIE
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