043
FXUS63 KUNR 172136
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
236 PM MST TUE DEC 17 2024
KEY MESSAGES
- PATCHY FREEZING FOG POSSIBLE TONIGHT ACROSS THE WESTERN SD
PLAINS
- A CLIPPER SYSTEM WILL BRING SOME CHANCES FOR LIGHT MIXED PCPN
ACROSS MAINLY NORTHWEST SD WEDNESDAY NIGHT AND POTENTIALLY
STRONG NORTHWEST WINDS ACROSS THE SOUTH DAKOTA PLAINS ON
THURSDAY.
- MOSTLY DRY CONDITIONS ARE EXPECTED LATE WEEK AND OVER THE
WEEKEND, WITH TEMPERATURES NEAR TO ABOVE AVERAGE ACROSS MOST OF
THE AREA.
DISCUSSION
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 234 PM MST TUE DEC 17 2024
UPPER AIR ANALYSIS SHOWS A LONGWAVE TROUGH CROSSING THE CENTRAL
CONUS. THE MAIN AXIS HAS SHIFTED EAST OF THE CWA, WITH SNOW ACROSS
EASTERN SD AND SOUTHERN MN. KUDX RADAR AND SURFACE OBS DO SHOW SOME
LINGERING LIGHT SNOW SHOWERS ACROSS FAR NORTHWEST SD. THIS PRECIP
WILL END LATE THIS AFTERNOON. SURFACE HIGH PRESSURE IS BUILDING IN
FROM THE NORTHWEST. QUIET WEATHER IS EXPECTED TONIGHT, WITH LIGHT
WINDS. MODELS ARE SHOWING THE POSSIBILITY FOR PATCHY FREEZING FOG
AFTER 06Z ACROSS PORTIONS OF THE WESTERN SD PLAINS, PERSISTING TO
JUST AFTER SUNRISE. QUIET WEATHER WILL CONTINUE THROUGH WEDNESDAY.
WARM AIR ADVECTION LATE TONIGHT THROUGH THE DAY TOMORROW WILL BRING
HIGHS AROUND 30 IN CENTRAL SD TO NEAR 50 ACROSS SW SD AND NE WY. A
FAST-MOVING CLIPPER SYSTEM WILL CROSS THE NORTHERN ROCKIES TOMORROW,
THEN THE DAKOTAS WEDNESDAY NIGHT. THIS WILL BRING A QUICK SHOT OF
PRECIPITATION MAINLY TO ND AND EAST RIVER, BUT IT LOOKS LIKE
NORTHWEST SD TO THE BLACK HILLS MAY GET CLIPPED. CAMS SHOW RAIN/SNOW
SHOWERS CROSSING NW SD DURING THE WEDNESDAY EVENING HOURS. WITH THE
WARMING LOW LEVELS AND GROUND TEMPERATURES BELOW FREEZING, SOME
FREEZING RAIN WILL BE POSSIBLE. QPF WILL BE VERY LIGHT, AND
TEMPERATURES ARE EXPECTED TO WARM TO NEAR OR ABOVE FREEZING BY 06Z,
SO THAT WILL ALSO LIMIT ANY POTENTIAL ICING IMPACTS. BEHIND THE
WAVE, A COLD FRONT WILL CROSS THE AREA EARLY THURSDAY MORNING.
STRONG NW WINDS WITH GUSTS TO 50-55 MPH ARE POSSIBLE MAINLY ACROSS
WESTERN TO CENTRAL SD. RIGHT NOW IT LOOKS LIKE A HIGH-END WIND
ADVISORY EVENT, BUT THERE SOME POTENTIAL FOR GUSTS TO 60 MPH OVER
FAR NW SD. WILL LET LATER SHIFTS REASSESS. STRONG UPPER RIDGING
BUILDS ACROSS THE REGION FOR THE END OF THE WEEK, BRINGING DRY AND
MILD CONDITIONS TO THE AREA.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY)
ISSUED AT 1050 AM MST TUE DEC 17 2024
MVFR/IFR CIGS WILL PERSIST ACROSS WESTERN SD THIS AFTERNOON WITH
SOME GENERAL IMPROVEMENT, AS DRIER AIR MOVES IN THIS AFTERNOON
AND EVENING. STRATUS/FOG MAY DEVELOP OVERNIGHT TONIGHT, WITH LOCAL
MVFR/IFR CONDITIONS DEVELOPING AGAIN AND PERSISTING THROUGH THE
MORNING HOURS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...13
AVIATION...13
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