109
FXUS63 KUNR 151811
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1211 PM MDT SUN MAR 15 2026
KEY MESSAGES
- MODERATE TO OCCASIONALLY HEAVY SNOW STILL EXPECTED THROUGH
SUNDAY MORNING.
- GUSTY NORTHWEST WINDS FROM 40 TO 50 MPH OVERNIGHT WILL CREATE
AREAS OF BLOWING AND DRIFTING SNOW.
- BELOW NORMAL TEMPERATURES FOR SUNDAY AND MONDAY, THEN WARM AND
DRY FOR THE REMAINDER OF THE WEEK.
UPDATE
ISSUED AT 1029 PM MDT SAT MAR 14 2026
MODERATE TO HEAVY SNOW HAS DEVELOPED ALONG BAND OF 700MB FGEN AND
IS PUSHING THROUGH THE CWA AT THIS HOUR. CURRENT RADAR IMAGERY
SHOWS THE HEAVIEST SNOW STRETCHING FROM EXTREME SOUTHWESTERN SD
NORTHEASTWARD INTO NORTHERN JACKSON/SOUTHERN HAAKON COUNTIES.
A GLANCE AT AREA WEBCAMS SHOW VISIBILITIES ALONG ROADWAYS HAVE
DECREASED TO LESS THAN A MILE IN SOME SPOTS WITH SOME SPORADIC
WHITE OUT CONDITIONS. SFC LOW CONTINUES TO DEEPEN ACROSS WESTERN
KS/NE WITH 3-HR PRESSURE RISES OF 4-5 MB ACROSS NORTHEASTERN WY
AND STRONG CAA SUPPORTING WIND GUSTS OF 30-40 MPH.
FORECAST REMAINS ON TRACK WITH LITTLE CHANGE IN EXPECTED SNOWFALL
TOTALS. HOWEVER, BANDING MAY RESULT IN LOCALLY HIGHER AMOUNTS,
ESPECIALLY ACROSS SOUTHWESTERN SD AND THE SOUTHERN BLACK HILLS.
WINDS WILL CONTINUE TO INCREASE THROUGH THE OVERNIGHT HOURS AS
THE SFC LOW CONTINUES TO DEEPEN AND TRACK TO THE EAST. 3 HR
PRESSURE RISES OF 5-7 MB WILL SUPPORT GUSTY NORTHERLY WINDS SUNDAY
MORNING WITH NBM PAINTING ~70-90% PROBS OF GUSTS EXCEEDING 45 MPH
OVER MUCH OF THE WESTERN SD PLAINS ALONG AND SOUTH OF I-90. THIS
WILL SUPPORT WIDESPREAD BLOWING SNOW ACROSS MUCH OF THE WESTERN SD
PLAINS THROUGH THE DAY SUNDAY. HAVE MADE NO CHANGES TO THE CURRENT
HEADLINES.
DISCUSSION
(THIS EVENING THROUGH SATURDAY)
ISSUED AT 1226 PM MDT SAT MAR 14 2026
UPPER LEVEL ANALYSIS SHOWS QUICK MOVING ZONAL FLOW ALOFT
CURRENTLY WITH DIGGING TROUGH LOCATED ACROSS WESTERN MT/EASTERN
ID. FAIRLY DECENT BAROCLINIC LEAF SHIELD DEVELOPING AHEAD OF THIS
TROUGH ACROSS THE ROCKIES. AT THE SURFACE, BAROCLINIC ZONE IS
DRAPED FROM NORTHWEST WY SOUTHEAST THROUGH THE NEB PANHANDLE AND
ALONG THE NEB/SD BORDER. SOUTH OF THIS BOUNDARY, TEMPS HAVE RISEN
INTO THE MID 40S TO MID 50S WHILE NORTH OF THE BOUNDARY, TEMPS ARE
STRUGGLING INTO THE MID 20S TO MID 30S.
RADAR TRENDS CONT TO SHOW INCREASING AREA OF LIGHT SNOW ACROSS NW
SD, WITH AREA WEBCAMS SHOWING AREAS OF LIGHT SNOW VERIFYING RADAR
SIGNATURES. VISIBLE SAT IMAGERY SUGGESTS THAT THERE MIGHT BE SOME
MINOR CONVECTIVE COMPONENTS ASSOCIATED WITH LIGHT SNOWFALL, WHICH
ALSO ALIGNS WELL WITH STEEPING LL LAPSE RATES AHEAD OF COLD FRONT
THAT IS SAGGING SOUTH INTO NORTHWEST SD FROM ND.
FOR THE OVERNIGHT HOURS INTO SUNDAY, 700HPA LOW CLOSES OFF AND
DROPS SOUTHEAST THROUGH THE UPPER MIDWEST AS AN AREA OF LOW
PRESSURE FORMS ON THE SOUTHERN BAROCLINIC BOUNDARY, STRENGTHENS
AND MOVES EAST. FOLLOWING THE COLD FRONT, VERY STRONG PRESSURE
RISES FOLLOW WHICH WILL AID IN STRENGTHENING THE NORTHWEST WINDS.
3-HRLY PRESSURE RISES FROM 7-9MB ARE SHOWN IN THE 15/06Z TO 15/12Z
TIME FRAME. ENSEMBLES ARE SHOWING PROBABILITIES OF WIND GUSTS > 45
MPH BY 12Z SUNDAY IN THE 35%'ISH RANGE, WHILE PROBABILITIES OF
WIND GUSTS > 50 MPH IN THE 20%'ISH RANGE FOR PARTS OF THE BH
FOOTHILLS AND SECTIONS OF THE WESTERN SD PLAINS. WHILE SNOW TOTALS
STILL APPEAR TO BE TRENDING DOWN SLIGHTLY, THE STRONG WINDS WILL
STILL CREATE VSBY ISSUES WITH BLOWING AND DRIFTING SNOW. ENDED UP
INCREASING OVERNIGHT WINDS A BIT TOWARD THE NBM 75 PERCENTILE
RANGE. IT SEEMS LATELY THAT ACTUAL WINDS HAVE OVERPERFORMED WHAT
THE ACTUAL MODELS HAVE ADVERTISED. WITH THE STRONG CAA ALSO TAKING
PLACE, SNOW RATIOS WILL ALSO INCREASE TO 15-20 TO 1, LEADING TO
SOME FLUFFIER SNOW, WHICH WILL BE EASIER TO PICK UP AND BLOW
AROUND. UPSLOPE SNOW CONDITIONS ARE STILL IN STORE FOR THE
NORTHERN BH AND FOOTHILLS, AND LOCALIZED HEAVY AMOUNTS ARE
CERTAINLY POSSIBLE. OVERALL, WHILE SNOWFALL TOTALS CONT TO TREND
DOWN SLIGHTLY, WITH THE STRONG WINDS, FORECASTED WIND CHILLS BY
SUNDAY MORNING, AND VSBY IMPACTS DUE TO BLOWING AND DRIFTING SNOW,
THIS STILL HAS THE POTENTIAL TO BE A VERY IMPACTFUL STORM.
IT WILL DRY OUT SUNDAY AFTERNOON, AND REMAIN GENERALLY DRY FOR THE
REMAINDER OF THE WEEK. SUB-SEASONAL NORMAL TEMPERATURES ARE
EXPECTED FOR SUNDAY NIGHT AND MONDAY WITH OVERNIGHT LOWS SUNDAY
NIGHT FALLING INTO THE SINGLE DIGITS. BUILDING 500HPA RIDGE
THROUGH THE REST OF THE WEEK WILL BRING WARMING CONDITIONS
BEGINNING TUESDAY AND CARRYING THROUGH THE REST OF THE WEEK.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1211 PM MDT SUN MAR 15 2026
STRONG NORTHWEST WINDS CONTINUE TO PRODUCE AREAS OF BLOWING SNOW
AND IFR VSBYS IN THE WAKE OF THIS MORNING'S WINTER STORM, WITH
SOME LOW CLOUDS HOLDING ON AT KGCC AND A FEW DIMINISHING SNOW
SHOWERS STILL OUT AND ABOUT AS WELL. MODEL GUIDANCE HAS BEEN
RELATIVELY USELESS IN ACCURATELY CAPTURING TRENDS THIS MORNING, SO
FORECAST CONFIDENCE ON EXACT TIMING FOR IMPROVEMENT ON ANY OF
THESE ELEMENTS IS RELATIVELY LOW. WINDS ARE FORECAST TO GRADUALLY
DECREASE OVER THE NEXT SEVERAL HOURS AND THEN DROP OFF
DEFINITIVELY BY SUNSET, THUS ALL TERMINALS SHOULD RETURN TO VFR
CONDITIONS AT LEAST BY 00-01Z/6-7PM, IF NOT SOONER. WILL CONTINUE
TO MONITOR SFC OBS AND AMEND AS NEEDED. VERY LIGHT WINDS AND JUST
A FEW HIGH-LEVEL PASSING CLOUDS ARE EXPECTED TONIGHT AS QUIETER
WEATHER SETTLES IN.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...WONG
DISCUSSION/KEY MESSAGES...HINTZ
AVIATION...KSMITH
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