925
FXUS65 KBOU 251040
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
340 AM MST SAT JAN 25 2025
KEY MESSAGES
- SNOW CONTINUES ALONG AND NORTH OF I-70 TODAY, MAINLY LIGHT BUT
WITH SOME TRAVEL IMPACTS FOR THE MOUNTAINS AND EAST TO THE I-25
CORRIDOR.
- DRY WEATHER EXPECTED EARLY NEXT WEEK WITH MODERATING TEMPERATURES.
- STILL WATCHING THE POTENTIAL RETURN OF SNOW (20-30% CHANCE)
TOWARDS MIDDLE/LATE NEXT WEEK. CONFIDENCE REMAINS LOW.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 340 AM MST SAT JAN 25 2025
CURRENT RADAR AND OBSERVATIONS SHOW SNOW HAS SPREAD EAST AND SOUTH
OFF THE FOOTHILLS AND CHEYENNE RIDGE EARLY THIS MORNING AS THE
LOWER LAYERS HAVE FINALLY MOISTENED UP. RELATIVELY WEAK NNE WINDS
(~10KTS) ARE PROVIDING SOME UPSLOPE ENHANCEMENT ALONG THE FRONT
RANGE, HOWEVER, IT REMAINS FAIRLY SHALLOW AS IT RESIDES BELOW THE
700MB LEVEL. WHERE LOW CEILINGS ~600' HAVE BEEN OFF AND ON ACROSS
OUR TAF SITES, THIS HAS REMAINED FAIRLY DENSE FOG FOR OUR HIGHER
ELEVATIONS ALONG PORTIONS OF I-70 IN JEFFERSON COUNTY WHERE A
WINTER WEATHER ADVISORY IS IN EFFECT, BUT THIS HAS BEGUN A
TRANSITION TO SNOW SHOWERS AND NO DENSE FOG ADVISORY WILL BE
NEEDED. THE SPC MESOANALYSIS INDICATES A NEAR 3000' DENDRITIC
LAYER DEPTH ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA, WITH
~4000' DEPTH ALONG THE WYOMING BORDER WHERE JET SUPPORT AND
FRONTOGENESIS IS GREATEST AT THIS TIME. THIS LAYER IS EXPECTED TO
DEEPEN PRIOR TO SUNRISE (~6000 TO 9000'), ALLOWING FOR SOME
INCREASED SNOW RATIOS, AND MAKING FOR SOME FLUFFY SNOWFLAKES. WE
ARE STILL EXPECTING PERSISTENT QG ASCENT THROUGH THE MORNING WITH
OUR HEAVIEST SNOWFALL OCCURRING BETWEEN 5AM AND 11AM THIS MORNING.
CURRENT WINTER HIGHLIGHTS WILL BE ALLOWED TO CONTINUE AS THE
FORECAST LOOKS TO BE ON TRACK, WITH ONLY MINOR ADJUSTMENTS
NEEDED. THOSE WHO ARE VENTURING OUT INTO THE MOUNTAINS AND
FOOTHILLS TODAY SHOULD BE PREPARED FOR WINTER DRIVING CONDITIONS
AS ROADS ARE EXPECTED TO BE SLICK AND SNOW COVERED.
TEMPERATURES WON'T BUDGE MUCH TODAY AS 700MB TEMPERATURES STAY IN
THE -15 TO -18C RANGE. WE EXPECT A 5 TO 10F WARMUP FOR HIGH
TEMPS ACROSS THE FORECAST AREA FROM THIS MORNINGS FORECAST LOWS.
CONDITIONS ARE EXPECTED TO IMPROVE LATER THIS EVENING FROM EAST TO
WEST ACROSS THE PLAINS WHEN NE UPSLOPE FLOW SUBSIDES AND THE JET
PUSHES EAST. WITH SURFACE WINDS EXPECTED TO MAKE A SHIFT TO THE
SOUTHEAST IN THE EVENING, SNOW MAY LINGER A LITTLE LONGER FOR THE
NORTHERN FOOTHILLS AND AROUND FORT COLLINS WHERE THE SOUTHEAST
WINDS WILL REINFORCE A NEW UPSLOPE COMPONENT, ALBEIT VERY WEAK AND
SHALLOW. HAVE HELD ON TO POPS INTO EARLY SUNDAY MORNING FOR
EASTERN LARIMER COUNTY TO ACCOUNT FOR THIS. THE MOUNTAINS WILL BE
THE LAST TO SHUTOFF AS OROGRAPHICS WILL KEEP SNOW SHOWERS GOING
INTO THE MORNING.
LONG TERM /SUNDAY THROUGH FRIDAY/
ISSUED AT 340 AM MST SAT JAN 25 2025
WE'LL CAP OFF THE WEEKEND DRIER, BUT WITH CONTINUED COOL/CLOUDY
CONDITIONS. GUIDANCE IS RATHER BEARISH ON TEMPERATURES FOR SUNDAY,
ESPECIALLY THOSE WHICH MAINTAIN SOME STRATUS INTO THE EARLY
AFTERNOON HOURS. HIGHS MAY STRUGGLE TO REACH THE UPPER 20S. ANY
LINGERING MOUNTAIN SNOW SHOULD QUICKLY END DURING THE DAY AS
MOISTURE QUICKLY FADES OUT OF THE REGION. OVERNIGHT LOWS WILL ALSO
BE FAIRLY CHILLY, WITH SOME SINGLE DIGIT READINGS POSSIBLE ACROSS
PORTIONS OF THE I-25 CORRIDOR.
THE START OF NEXT WEEK SHOULD BE VERY QUIET. MOST OF THE REGION
WILL BE IN A COL (WHICH IS EVIDENTLY THE DAY SHIFT'S FAVORITE
WORD), STUCK IN BETWEEN THE MEANDERING UPPER LOW TO THE SOUTHWEST,
AND THE BROADER FLOW ALOFT TO THE NORTHEAST. THIS WILL LEAD TO A
QUIESCENT FORECAST FOR A FEW DAYS, WITH HIGHS IN THE LOW TO MID
40S AND LITTLE ELSE.
AT SOME POINT LATER IN THE WEEK, THAT UPPER LEVEL LOW IS EXPECTED
TO SHIFT EAST AND EVENTUALLY EJECT INTO THE CENTRAL GREAT PLAINS,
BUT THAT'S ABOUT THE ONLY THING WE CAN SAY WITH CONFIDENCE.
CONSIDERABLE UNCERTAINTY REMAINS IN THIS PERIOD, AND THE NBM
SOLUTION (SLIGHT CHANCE POPS FOR A COUPLE DAYS) IS PROBABLY THE
BEST WAY TO HANDLE THIS FOR NOW. THIS SYSTEM IS WORTH WATCHING -
AS A FEW ENSEMBLE MEMBERS ARE VERY SNOWY FOR THE EASTERN PLAINS -
BUT A MAJORITY OF GUIDANCE KEEPS MOST OF THE QPF WELL TO OUR
SOUTH/EAST. WE'LL HOPE FOR BETTER CONSISTENCY AS WE GET THROUGH
THIS WEEKEND.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1026 PM MST FRI JAN 24 2025
THINGS ARE STARTING TO FILL IN AND CEILINGS ARE LOWERING AROUND
THE TAF SITES AT THIS TIME. KDEN IS SHOWING THE FIRST SIGNS OF
THE APPROACHING WINTER SYSTEM WITH IFR CONDITIONS QUICKLY
DEVELOPING, AND KAPA/KBJC ARE EXPECTED TO FOLLOW SUIT. SNOW IS
EXPECTED TO DEVELOP WITHIN THE NEXT TWO HOURS, WHICH WILL CAUSE
VISIBILITIES TO DECREASE, DROPPING AS LOW AS 1SM PRIOR TO SUNRISE. WE
ARE STILL EXPECTING PERIODS OF MVFR AND IFR THROUGH AROUND 21Z
SATURDAY AT ALL TAF SITES. ACCUMULATIONS OF 1 TO 3 INCHES OF SNOW
ARE STILL EXPECTED AT KDEN/KAPA AND 3 TO 6 INCHES AT KBJC.
BOU WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ030-
032-035-039.
WINTER WEATHER ADVISORY UNTIL 5 AM MST SUNDAY FOR COZ031-033.
SHORT TERM...BONNER
LONG TERM...HIRIS
AVIATION...BONNER
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