884
FXUS65 KBOU 260039
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
539 PM MST SAT JAN 25 2025
KEY MESSAGES
- LIGHT SNOW THIS CONTINUES, DECREASING OVERNIGHT ON THE PLAINS,
LINGERING OVER THE MOUNTAINS INTO SUNDAY.
- 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 SUNDAY/
ISSUED AT 240 PM MST SAT JAN 25 2025
LIGHT SNOW IS CONTINUING OVER THE CWA THIS AFTERNOON FROM
THE DIVIDE EASTWARD WELL INTO THE PLAINS. THE UPSLOPE IS PRETTY
SHALLOW; ONLY THREE GATES DEEP ON THE KFTG VAD WIND PROFILER AT THIS
TIME. THERE IS A NARROW BAND OF LIGHT SNOW STRETCHING WEST TO
EAST FROM SOUTHERN JACKSON COUNTY INTO SOUTHERN LOGAN COUNTY. THE
SNOWFALL RATES ARE PRETTY LOW, 1/4 INCH PER HOUR AT BEST.
MODELS HAVE FAIRLY STRONG WEST-SOUTHWESTERLY FLOW ALOFT TONIGHT,
THEN MORE DUE WESTERLY ON SUNDAY. THERE IS WEAK UPWARD SYNOPTIC
SCALE ENERGY FOR THE CWA TONIGHT, THEN WEAK SUBSIDENCE ON SUNDAY.
THE LOW LEVEL PRESSURE GRADIENT AND WIND FIELDS KEEP THE WINDS
WEAK TONIGHT AND SUNDAY WITH NORMAL DIURNAL PATTERNS TO PREVAIL
BEFORE SUNRISE SUNDAY MORNING.
AS FAR AS ADDITIONAL SNOWFALL GOES, MODELS DO KEEP LIGHT SNOW GOING
THROUGH THIS EVENING, THEN SLOWLY DECREASE AND END IT OVERNIGHT
OVER THE PLAINS. IT HANGS OF LONGER IN THE MOUNTAINS ON SUNDAY,
MAINLY WITH 20-50% POPS MUCH OF THE DAY FOR LIGHT SNOW SHOWERS. I
WILL LEAVE THE HIGHLIGHTS GOING, AS IS, FOR THIS UPDATE.
FOR LOW TEMPERATURES TONIGHT, THE PLAINS LOOK TO BE ABOUT, 15
DEGREES BELOW SEASONAL NORMALS, WITH MOST AREAS DROPPING INTO THE
SINGLE DIGITS FOR OVERNIGHT LOWS. THE HIGH MOUNTAIN VALLEYS WILL
NOT GET EXTREME COLD TONIGHT WITH ALL THE CLOUD COVER EXPECTED.
FOR HIGHS ON SUNDAY, THE PLAINS LOOK TO STAY IN 20S.
LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/
ISSUED AT 131 PM MST SAT JAN 25 2025
CLOUDS WILL BE CLEARING OUT SUNDAY NIGHT, SO LOWERED THE
TEMPERATURES FOR OVERNIGHT LOWS AS THE CLEARER SKIES AND FRESH SNOW
WILL MAKE THE MOUNTAIN VALLEYS COLDER THAN WHAT GUIDANCE SAYS.
STARTING MONDAY, QUIET WEATHER IS EXPECTED FOR MOST OF THE WEEK DUE
TO OUR REGION BEING IN BETWEEN TWO SYSTEMS. A CLOSED UPPER LEVEL LOW
WILL BE SITUATED OVER CALIFORNIA AND AN UPPER LEVEL TROUGH WILL BE
TO OUR NORTHEAST, LEAVING OUR REGION UNDER WEAK FLOW ALOFT (AKA A
COL). HIGH TEMPERATURES WILL BOUNCE BACK TO SEASONAL NORMALS THIS
WEEK.
BY THE END OF WEEK, BETWEEN THURSDAY NIGHT AND SATURDAY, THE UPPER
LEVEL LOW IN OUR SOUTHWEST WILL FINALLY TRAVERSE EAST. ENSEMBLES ARE
STILL NOT IN AGREEMENT ON THE TIMING, ALTHOUGH MOST ARE TRENDING
SLOWER. RECENT MODEL GUIDANCE ALSO DISAGREE ON THE AVAILABLE
MOISTURE FOR PRECIPITATION WITH THIS SYSTEM. CMC AND ECMWF BOTH HAVE
TRENDED DOWN ON MOISTURE WITH MINIMAL SNOW FALLING IN THE PLAINS,
BUT THE GEFS HAS TRENDED UPWARD IN MOISTURE. IF I WERE TO WISHCAST
(AS THE MIDNIGHT SHIFT LIKES TO DO), SOME OF THE RUNS OF THE GFS
ENSEMBLE HAS DENVER RECEIVING OVER 6" OF SNOW (10-20%). HOWEVER,
THIS IS VERY UNLIKELY TO MATERIALIZE. A COUPLE OF INCHES COULD FALL
SOMETIME FRIDAY OR SATURDAY FOR THE PLAINS. DUE TO THE WARM
TEMPERATURES, THERE COULD ALSO BE A MIX OF RAIN AND SNOW SHOWERS.
REGARDLESS, THIS SYSTEM WILL HAVE TO BE MONITORED AND MOST LIKELY
THE FORECAST WILL CHANGE. BECAUSE OF THE UNCERTAINTY, WE WILL STICK
TO STAYING WITH NBM GUIDANCE UNTIL WE CAN GET CONSISTENCY IN THE
MODELS.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 529 PM MST SAT JAN 25 2025
SNOW IS GENERALLY DECREASING IN COVERAGE AND INTENSITY THIS
EVENING. THAT TREND SHOULD CONTINUE ALTHOUGH THERE COULD BE SOME
BRIEF PERIODS OF SNOW THAT TAKES VISIBILITY DOWN TO 3 SM AT KBJC
AND KAPA. STRATUS IS EXPECTED TO CONTINUE TONIGHT AND WILL LOWER
BY 09-12Z. THERE MAY ALSO BE SOME BR THAT DEVELOPS WITH VISIBILITY
AROUND 3-4 SM BUT FOG IS NOT EXPECTED. WINDS WILL BE LIGHT TONIGHT
AND TOMORROW SO THE LOW STRATUS WILL NOT GO ANYWHERE FAST. WITH
MINIMAL MIXING AND AN INVERSION OVERHEAD, THE STRATUS MAY STAY
UNTIL AROUND 20-21Z TOMORROW ALTHOUGH IT COULD STAY AS LONG AS
00Z. VFR CONDITIONS RETURN TOMORROW AFTERNOON THROUGH THE NIGHT.
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...RJK
LONG TERM....BARJENBRUCH/IDEKER
AVIATION...DANIELSON
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