525
FXUS63 KUNR 162253
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
353 PM MST SAT NOV 16 2024
KEY MESSAGES
- WIND SUBSIDES LATE THIS AFTERNOON
- SEASONAL WEATHER SUNDAY THROUGH MONDAY AFTERNOON
- COLDER, WINDY WEATHER TUESDAY AND WEDNESDAY WITH A CHANCE OF
RAIN OR SNOW MONDAY NIGHT AND TUESDAY LEADING TO MINOR IMPACTS
UPDATE
ISSUED AT 353 PM MST SAT NOV 16 2024
WITH WIND GUSTS WELL BELOW 40 MPH ACROSS NORTHWESTERN SD, OPTED TO
CANCEL THE WIND ADVISORY A COUPLE OF HOURS EARLY. STEADY WEST TO
NORTHWEST WINDS WILL PERSIST OVER MUCH OF WESTERN SD THROUGH THE
DAYLIGHT HOURS, WITH MAXIMUM GUSTS GENERALLY AROUND 35 MPH.
DISCUSSION
(THIS EVENING THROUGH SATURDAY)
ISSUED AT 159 PM MST SAT NOV 16 2024
20Z SURFACE ANALYSIS HAD LOW OVER EASTERN ND WITH COLD FRONT INTO
CENTRAL NE. TIGHT PRESSURE GRADIENT BEHIND FRONT WITH MODEST COLD
AIR ADVECTION/ISALLOBARIC FORCING RESULTING IN GUSTY NORTHWEST
WINDS (CURRENTLY PEAKING AROUND 45MPH) OVER NORTHWESTERN SD. WILL
LET WIND ADVISORY RIDE. WATER VAPOUR MATINEE DEPICTED UPPER
TROUGH FROM SK TO NORTHERN MEXICO WITH COMPACT UPPER LOW OVER
NORTHWESTERN ND. WEAK FORCING/MOISTURE ASSOCIATED WITH UPPER LOW
CREATING STRATUS/STRATOCU OVER NORTHWEST HALF OF CWA AND A BAND
OF LIGHT SNOW. MINOR ACCUMULATIONS NOTED OVER THE HIGHER TERRAIN
PER WEBCAMS. PRECIPITATION STRUGGLING TO REACH THE GROUND AND
ACCUMULATE ON THE PLAINS GIVEN MARGINAL TEMPERATURES. CONCERN THIS
FORECAST REVOLVES UPPER LOW EMERGING OUT OF NORTHERN MEXICO.
TONIGHT THROUGH MONDAY AFTERNOON, LOW AMPLITUDE UPPER RIDGE
SNEAKS ACROSS THE NORTHERN ROCKIES INTO THE PLAINS IN RESPONSE TO
UPPER TROUGH BEING CARVED OUT OVER THE NORTHWEST CONUS. LOW LEVEL
WARM AIR ADVECTION WILL PROMOTE MILD HIGHS SUNDAY AND MONDAY, BUT
NEAR GUIDANCE.
MONDAY NIGHT THROUGH WEDNESDAY, CONFIDENCE IS MEDIUM TO HIGH THAT
NORTHWEST CONUS UPPER TROUGH KICKS OUT UPPER LOW INTO SOUTHERN
PLAINS AND THEN UPPER MIDWEST. SURFACE LOW TRACKS FROM TX TO
NORTHERN WI, BEFORE IT OCCLUDES UNDER NEW UPPER LOW OVER FORMING
OVER ND. THIS PATTERN TOO FAR EAST FOR HIGH IMPACT EVENT OVER THE
CWA, BUT COLD FRONT MONDAY NIGHT ASSOCIATED WITH NORTHERN UPPER
TROUGH WILL BRING A BAND OF LIGHT SNOW TO NORTHEASTERN WY/BLACK
HILLS/FAR NORTHWEST SD. SNOW ACCUMULATIONS WILL BE LIGHT (40-70%
CHANCE <1" PER LREF WITH A 30% CHANCE OF 2" OVER THE HIGHER BEAR
LODGE MOUNTAINS). STRONG, GUSTY NORTHWEST WINDS (50% CHANCE >50MPH
GUSTS PER NBM) EXPECTED TUESDAY AND WEDNESDAY GIVEN TIGHT
GRADIENT AND LIKELY SECONDARY SURFACE TROUGH SLIDING THROUGH THE
AREA WEDNESDAY. TEMPERATURES WILL BE 5-10F BELOW NORMAL, BUT NEAR
GUIDANCE.
UPPER RIDGE POPS UP OVER THE ROCKIES FOR THE END OF THE FORECAST
WITH A RETURN TO MILD AND MOSTLY DRY WEATHER.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 353 PM MST SAT NOV 16 2024
MVFR/IFR CONDITIONS IN LOW STRATUS AND SOME LIGHT SNOW CONTINUE
ACROSS THE NORTHERN BLACK HILLS, ADJACENT FOOTHILLS, AND
NORTHWESTERN SD PLAINS. GRADUAL IMPROVEMENT FROM WEST TO EAST IS
EXPECTED OVER THE NEXT SEVERAL HOURS, WITH VFR CONDITIONS PREVAILING
AREA-WIDE BY AROUND 06Z. SOUTH/SOUTHWEST RETURN FLOW WILL BECOME
BREEZY OVER PORTIONS OF NORTHEASTERN WY AND SOUTHWESTERN TO SOUTH
CENTRAL SD AFTER 12Z.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...SHERBURN
DISCUSSION/KEY MESSAGES...HELGESON
AVIATION...SHERBURN
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