521
FXUS65 KBOU 302039
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
139 PM MST SUN NOV 30 2025
KEY MESSAGES
- DETERIORATING MOUNTAIN TRAVEL CONDITIONS ENTERING SUNDAY NIGHT
AS HIGH COUNTRY SNOW INCREASES.
- LIGHT SNOW SUNDAY EVENING FOR THE URBAN CORRIDOR/PLAINS. HIGHLY
LOCALIZED 1-3" ACCUMULATIONS UNDER HEAVIEST BANDS, MAINLY SOUTH
OF I-70.
- REMAINING VERY COLD THROUGH MONDAY.
- INCREASING CONFIDENCE IN RETURN OF SNOW TO MOST AREAS WEDNESDAY,
INCLUDING HIGHEST POTENTIAL FOR LOWER ELEVATION TRAVEL IMPACTS
SO FAR THIS SEASON.
DISCUSSION /THROUGH SUNDAY/
ISSUED AT 1234 PM MST SUN NOV 30 2025
SNOWFALL HAS DEVELOPED ON SCHEDULE IN OUR HIGH COUNTRY AND WILL
CONTINUE TO INCREASE IN THE AFTERNOON UNDER A DEEPENING MOISTURE
COLUMN. UPSTREAM OBSERVATIONS SO WIDESPREAD PRECIPITATION ACROSS
THE WESTERN SLOPE, AND WE CAN EXPECT TRAVEL CONDITIONS IN OUR
MOUNTAINS TO DETERIORATE STEADILY IN THE COMING HOURS AS THIS
MIGRATES EASTWARD. THE OVERALL PICTURE THROUGH TONIGHT REMAINS
RELATIVELY UNCHANGED, WITH SOME BANDED SNOW SHOWERS EXPECTED TO
SPILL INTO THE URBAN CORRIDOR AS EARLY AS 4-5PM, BUT MOSTLY INTO
THE EVENING HOURS. THE BETTER POTENTIAL FOR THESE BANDS WILL BE
ROUGHLY SOUTH OF I-70 AS DESCRIBED IN PREVIOUS DISCUSSIONS, OWING
TO THE MORE FAVORABLE JET STREAK POSITION ALOFT AND DEEPEST
MOISTURE. MOST OF THE LOWER ELEVATIONS WILL RECEIVE LESS THAN 1",
BUT LOCALIZED NARROW CORRIDORS MAY ACCUMULATE 2 OR EVEN 3" UNDER
THE HEAVIEST/MOST PERSISTENT BANDS, ENOUGH FOR SOME ENHANCED
TRAVEL IMPACTS, AND MAY EXTEND INTO PORTIONS OF OUR SOUTHERN AND
EASTERN PLAINS. SNOWFALL ASIDE, TEMPERATURES HAVE BEEN NOTABLY
SLOW TO CLIMB, WITH MOST OF THE LOWER ELEVATIONS BARELY REACHING
INTO THE LOWER 20'S AS OF THIS WRITING. THIS TREND WILL CARRY OVER
INTO THE OVERNIGHT PERIOD, WITH ANOTHER COLD NIGHT AHEAD BRINGING
LOWS INTO THE SINGLE DIGITS TO LOW TEENS FOR MOST AREAS.
TUESDAY'S WARMING WILL BE MODEST AS THE TROUGH AXIS PUSHES EAST,
AND HAVE TRENDED HIGHS DOWNWARD SLIGHTLY KEEPING TEMPERATURES
FIRMLY IN THE 30'S ACROSS THE PLAINS/I-25 CORRIDOR, AND 20'S FOR
MOST MOUNTAIN COMMUNITIES. IT WILL BE AN OTHERWISE DRY DAY PAST
SUNRISE, WITH A DISTINCT LULL IN MOUNTAIN SNOW AND CLEARING SKIES
ACROSS THE REGION.
STRENGTHENING WESTERLY FLOW AHEAD OF A DEVELOPING TROUGH TO OUR
WEST WILL REIGNITE THE POTENTIAL FOR MOUNTAIN SNOW SHOWERS ON
TUESDAY, WITH RECENT RUNS A LITTLE MORE BULLISH ON ACCUMULATING
SNOW POTENTIAL, PARTICULARLY FOR THE PARK AND MEDICINE BOW RANGES.
AMOUNTS SHOULD NONETHELESS BE RATHER MINOR GIVEN STILL LIMITED
MOISTURE.
CONFIDENCE IN THE ARRIVAL OF ANOTHER STORM SYSTEM ON WEDNESDAY HAS
CONTINUED TO INCREASE WITH THE LATEST GUIDANCE, WHICH FAVORS A
SHEARING SHORTWAVE DESCENDING INTO AZ/NM BEFORE LIFTING NE INTO
THE PLAINS COME THURSDAY. THIS PATH EASILY GENERATES THE HIGHEST
POTENTIAL FOR WINTER WEATHER TRAVEL IMPACTS TO THE LOWER
ELEVATIONS YET THIS SEASON, EVEN IF QUESTIONS REMAIN REGARDING
ACCUMULATION AMOUNTS. THERE'S MODERATE CONSENSUS IN A PERIOD OF
MODEST NORTHEASTERLY UPSLOPE FLOW DURING THE DAY WEDNESDAY, WHICH
WOULD PROMOTE QUITE HIGH (~75-80%) PRECIPITATION PROBABILITIES FOR
OUR FOOTHILLS, DENVER METRO AND PALMER DIVIDE IN PARTICULAR.
HOWEVER, THE SYSTEM WON'T LACK SPEED, WITH ITS RAPID EASTWARD
MOTION BEING A LIMITING FACTOR IN SNOWFALL POTENTIAL. ENSEMBLE QPF
SPREAD APPEARS QUITE UNIMODAL AND SYMMETRIC, GENERALLY FAVORING
0.1-0.3" OF QPF FOR THE MOUNTAINS AND I-25 CORRIDOR WITH A SMALL
HANDFUL OF BOTH DRIER AND WETTER SCENARIOS. STILL TIME TO TREND
IN EITHER DIRECTION, OF COURSE.
AS THE LOW MERGES WITH THE BROADER SYNOPTIC FLOW THURSDAY, WE LOOK
TO RETURN TO A MORE PROGRESSIVE PATTERN WITH TROUGHING TO OUR
NORTH AND RIDGING IN THE VICINITY OF THE WEST COAST. THE NUANCES
IN THE PATTERN CAN'T YET BE DISCERNED, BUT THE DOOR WILL REMAIN
OPEN FOR THE PASSAGE OF A FEW SHORTWAVES UNDER NORTHWEST FLOW THAT
WOULD SUSTAIN A FEW WINDOWS FOR PREDOMINANTLY MOUNTAIN SNOWFALL.
WITH THE BULK OF THE TROUGHING EXPECT TO REMAIN TO THE NORTH, OUR
NORTHERN MOUNTAINS WILL BE MOST FAVORABLY POSITIONED FOR SOME
ADDITIONAL HEALTHY SNOWFALL DURING THE LATTER HALF OF THE WEEK.
THIS PATTERN ALSO LENDS ITSELF TO MORE ROBUST PRESSURE GRADIENT-
DRIVEN FLOW AND HENCE STRONGER WINDS ACROSS THE REGION.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1041 AM MST SUN NOV 30 2025
CLOUDS HAVE THICKENED AHEAD OF SCHEDULE THIS MORNING, WITH EVEN A
FEW SNOWFLAKES ALREADY OBSERVED AT KDEN OVER THE PAST HOUR OR SO.
LIGHT WINDS REMAIN IN PLACE ACROSS THE TAF SITES AND ARE STILL ON
TRACK TO SEE A TRANSITION TO THE SOUTHEAST THIS AFTERNOON AS A
SURFACE CYCLONE BECOMES MORE PRONOUNCED. CURRENT SSW WINDS AT KDEN
MAY BECOME MORE VARIABLE BEFORE THE SE WINDS PREVAIL BETWEEN
18-20Z. THE SAME IS EXPECTED AT KAPA. WINDS AT KBJC ARE EXPECTED
TO SEE A N TO NW TRANSITION THROUGH THE AFTERNOON.
A FEW CHANGES WERE MADE TO THE TAFS THIS MORNING AS GUIDANCE
SUGGESTS SLIGHTLY LOWER VISIBLITIES DROPPING TO AS LOW AS 1SM
EARLY THIS EVENING, WHEN SNOW MOVES FROM WEST TO EAST ACROSS THE
TAF SITES, BEGINNING FIRST AT KBJC BETWEEN 22-23Z, FOLLOWED BY
KDEN AND KAPA SHORTLY THEREAFTER. GENERALLY LIGHT SNOW
ACCUMULATIONS ARE EXPECTED ACROSS THE TAF SITES, THOUGH THE
INGREDIENTS WILL BE IN PLACE TO SEE POTENTIAL FOR SNOW BAND
DEVELOPMENT BETWEEN THE 0-6Z TIME FRAME THAT COULD BRING SOME
LOCALIZED HEAVIER AMOUNTS (UP TO 2 INCHES; KAPA:20-25%, KBJC:20%,
KDEN:15% CHANCE).
WHILE SOME SLIGHT CLEARING IS CURRENTLY OCCURRING WITH REGARDS TO
CEILINGS, THESE SHOULD GRADUALLY BEGIN LOWERING AGAIN AROUND 20Z,
WITH MVFR CONDITIONS EXPECTED THROUGH THE OVERNIGHT HOURS, WITH
SOME BRIEF PERIODS OF IFR CONDITIONS POSSIBLE. SHOULD SEE CLEARING
CONDITIONS EARLY MONDAY MORNING (13-15Z) WHEN WINDS TURN TOWARDS
THE WSW. EXPECTING ANOTHER GRADUAL SHIFT TOWARDS THE N TO NNE FOR
KDEN/KAPA THROUGH THE AFTERNOON, WITH KBJC HOLDING ONTO WSW WINDS
THROUGH THE DAY.
BOU WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ031-033-034.
DISCUSSION...BRQ
AVIATION...9
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