795
FXUS63 KUNR 260450
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
950 PM MST THU DEC 25 2025
KEY MESSAGES
- GUSTY WEST/SOUTHWEST WINDS THROUGH SATURDAY MORNING, THEN GUSTY
NORTHWEST WINDS BEHIND AN ARCTIC COLD FRONT SATURDAY
NIGHT/SUNDAY ALONG WITH PATCHY LIGHT SNOW
- UNSEASONABLY WARM TEMPERATURES CONTINUE THROUGH SATURDAY
AFTERNOON
DISCUSSION
(THIS EVENING THROUGH THURSDAY)
ISSUED AT 208 PM MST THU DEC 25 2025
21Z SURFACE ANALYSIS HAD LOW JUST NORTHEAST OF THE BLACK HILLS
WITH WARM FRONT FROM SOUTHWEST ND TO NORTHEAST NE. TIGHT PRESSURE
GRADIENT OVER THE BLACK HILLS STARTING RELAX WITH PEAK WIND GUSTS
DECLINING, SO HAVE ALLOWED WIND HEADLINES TO EXPIRE FOR THE BLACK
HILLS FOOTHILLS. RECORD-BREAKING TEMPERATURES THIS AFTERNOON
BEHIND THE WARM FRONT WITH 50S/60S/AROUND 70F. 18Z KUNR SOUNDING
SUPPORTED LOWER 70S, BUT THICKER CLOUD COVER PUT A LID ON HIGHS
FOR SOME. EXTENSIVE MID/HIGH CLOUDS OVER MUCH OF THE CWA AHEAD OF
A WEAK SHORTWAVE NOTED OVER WY/CO PER WATER VAPOUR LOOP. KUDX
RADAR SHOWING SOME RETURNS AHEAD OF WAVE, BUT MOST NOT REACHING
THE GROUND. PER 0.5KM VISIBLE LOOP, SOME BUMPINESS STARTING TO
EMERGE OVER THE BLACK HILLS INTO WY, SO HAVE INTRODUCED LOW POPS
TO ACCOUNT. WIDENING THE VIEW, UPPER LOW SPINS OFF THE WEST COAST
WITH ENTRENCHED SOUTHWEST FLOW FROM THE SOUTHWEST CONUS INTO THE
UPPER MIDWEST. THESE FEATURES THE MAIN CONCERN AGAIN THIS
AFTERNOON.
ENSEMBLE GUIDANCE IN GOOD AGREEMENT WITH MAIN SYNOPTIC FEATURES
THROUGH THE WEEKEND. SOUTHWEST FLOW ALOFT WILL PERSIST INTO
SATURDAY MORNING AS AN UPPER TROUGH/SHORTWAVE STARTS TO MOVE
ACROSS SOUTHERN CANADA INTO THE NORTHERN PLAINS. IT WILL SUSTAIN A
STRONG LOW LEVEL THERMAL RIDGE OVER THE CWA AHEAD OF AN ARCTIC
COLD FRONT THAT WILL PASS THROUGH LATE SATURDAY/SATURDAY NIGHT.
ISALLOBARIC FORCING BEHIND FRONT MODERATE WITH >50% CHANCE >45MPH
WIND GUSTS INTO SUNDAY MORNING PER ROBUST COLD AIR
ADVECTION/SUBSIDENCE. UPPER TROUGH/SHORTWAVE WILL BE MOISTURE-
STARVED, BUT SYNOPTIC FORCING COMBINED WITH RAPIDLY CONVERGING
T/TD LOWER TROPOSPHERIC THERMAL PROFILES WILL BE SUFFICIENT FOR
PATCHY LIGHT SNOW. NOT EXPECTING MUCH WITH THE BEST CHANCE FOR
ACCUMULATION OVER NORTHEASTERN WY/SOUTHWEST SD. TEMPERATURES WILL
BE NEAR GUIDANCE, EXCEPT A BIT LOWER OVER NORTHEAST REACHES OF THE
CWA CLOSEST TO SNOW COVER OVER ND/EASTERN SD.
NEXT WEEK, ENSEMBLE TEMPERATURES SPREADS INCREASE QUITE A BIT WITH
LOW LEVEL BAROCLINIC ZONE/COLD FRONT SNAKING IN/NEAR THE CWA. A LOW
CONFIDENCE TEMPERATURE FORECAST WITH THE MAIN QUESTION BEING HOW
MUCH ABOVE NORMAL WILL IT BE. HAVEN'T STRAYED FROM GUIDANCE AS A
RESULT. MOISTURE WILL BE SCANT.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 948 PM MST THU DEC 25 2025
VFR CONDITIONS WILL PERSIST THROUGH THE FORECAST PERIOD. BREEZY WEST
TO SOUTHWEST WINDS WILL CONTINUE ACROSS PORTIONS OF NORTHEASTERN
WY INTO THE BLACK HILLS WITH GUSTS OF 30-35 KT. LLWS WILL DEVELOP
ACROSS PORTIONS OF NORTHEASTERN WY AND SOUTHWESTERN SD AND
PERSIST INTO THE MORNING HOURS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HELGESON
AVIATION...WONG
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