472
FXUS65 KGJT 182324
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
424 PM MST SAT JAN 18 2025
KEY MESSAGES
- A PATTERN CHANGE IS UPON US AS AN ARCTIC FRONT HAS TRAVERSED
THE AREA BRINGING SNOW AND VERY COLD TEMPERATURES.
- A STRONG ARCTIC OUTBREAK IS EXPECTED TO CLOSE OUT THE WEEKEND
INTO EARLY NEXT WEEK ACROSS THE CENTRAL CONUS. THE COLDEST AIR
SHOULD REMAIN EAST OF THE DIVIDE BUT TEMPERATURES ON THIS SIDE
ARE FORECAST TO BE WELL-BELOW NORMAL. OVERNIGHT LOWS HAVE A
HIGH PROBABILITY OF DROPPING WELL-BELOW ZERO IN MANY MOUNTAIN
AND HIGH VALLEY/BASIN AREAS.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 359 PM MST SAT JAN 18 2025
INSTABILITY AIDED BY A MID-LEVEL SHORT WAVE TROUGH MOVING
SOUTHEASTWARD ACROSS THE SOUTHERN HALF OF THE FORECAST AREA HAS
KEPT SNOWFALL GOING OVER EAST-CENTRAL UTAH, WEST-CENTRAL
COLORADO AND THE SAN JUAN MOUNTAINS THIS AFTERNOON. MEANWHILE,
TEMPERATURES WERE STRUGGLING TO COME ANYWHERE NEAR NORMAL IN
COLD ADVECTIVE ENVIRONMENT.
SNOWFALL WILL LARGELY DISSIPATE THIS EVENING AS THE SHORT WAVE
TROUGH MENTIONED PREVIOUSLY PUSHES SOUTHEAST OF THE AREA AND 500
MB TEMPERATURES MODERATE CAUSING LAPSE RATES TO EASE. A FEW
LIGHT SNOW SHOWERS MAY PERSIST OVER THE ELKHEAD AND PARK
MOUNTAINS OVERNIGHT, THOUGH ANY ADDITIONAL ACCUMULATIONS WILL BE
LIGHT AND LOCALIZED. SINCE SNOW RATES DECREASE RAPIDLY LATE THIS
AFTERNOON, WILL ALLOW CURRENT WINTER WEATHER ADVISORIES TO
EXPIRE AT 00Z/SUN. SIMILARLY, WINDS WILL FALL OFF BEHIND THE
TROUGH SO THE WIND ADVISORIES FOR SOUTHWEST COLORADO WILL ALSO
BE ALLOWED TO FALL OFF AT 00Z. SUBSIDENCE WILL BRING CLEARING TO
MUCH OF THE REGION TONIGHT, THOUGH STRATUS WILL LINGER ON
NORTHWEST FACING SLOPES WELL INTO THE NIGHT. AS A RESULT,
TEMPERATURES ARE EXPECTED TO PLUMMET AFTER SUNSET WITH MANY
AREAS DROPPING BELOW FREEZING BY SUNRISE SUNDAY. DUE TO THE
LIKELIHOOD OF TEMPERATURES IN THE UPPER 20S AND LOWER 30S BELOW
ZERO IN THE UPPER YAMPA RIVER BASIN AND THE GUNNISON VALLEY
TONIGHT, A COLD WEATHER ADVISORY REMAINS IN EFFECT FOR THOSE
AREAS LATE TONIGHT THROUGH SUNDAY MORNING.
AFTER A BRIEF BREAK IN THE ACTION SUNDAY MORNING, SHOWERS WILL
REDEVELOP DURING THE AFTERNOON AS ANOTHER MID-LEVEL SHORT WAVE
TROUGH DIVES OUT OF THE NORTHERN ROCKIES. THE DISTURBANCE THEN
PUSHES SOUTH-SOUTHEASTWARD ACROSS THE FORECAST AREA ON SUNDAY
NIGHT. IN RESPONSE, SNOW SHOWERS BECOME LIKELY OVER THE NORTHERN
COLORADO MOUNTAINS SUNDAY AFTERNOON, EXPANDING SOUTHWARD INTO
THE CENTRAL COLORADO MOUNTAINS SUNDAY WITH MORE SCATTERED
SHOWER ACTIVITY OVER ADJACENT VALLEYS AND HIGHER TERRAIN TO THE
SOUTH. THOUGH SNOW RATIOS WILL BE HIGH, THE COLD AIRMASS WON'T
BE CARRYING MUCH MOISTURE SO ACCUMULATIONS ARE EXPECTED TO BE
FAIRLY LIGHT. SUSPECT THAT AS INPUT FROM SHORT RANGE MODELS
FACTORS IN WITH SUBSEQUENT RUNS WE'LL SEE AMOUNTS GO UP, BUT
PRETTY COMFORTABLE IN SAYING THAT ADVISORY LEVEL SNOW IS
UNLIKELY FOR NOW. AFTERNOON HIGHS WILL STRUGGLE TO RECOVER SO
HIGHS WILL CONTINUE TO RUN WELL BELOW NORMAL ON SUNDAY.
OVERNIGHT LOWS WILL CONTINUE TO BE COLD, BUT DUE TO CLOUD COVER
AND TROUGH PASSAGE SUNDAY NIGHT, EXPECT MONDAY MORNING LOWS WILL
BE LESS COLD. THAT SAID, FELT COLD WEATHER ADVISORY IN THE
GUNNISON BASIN STILL WARRANTED.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 359 PM MST SAT JAN 18 2025
THE LONG TERM BEGINS WITH A CHANCE OF SNOW ON MONDAY AND VERY COLD
TEMPERATURES. THE FORCING FOR SNOWFALL COMES FROM A PASSING
SHORTWAVE TROUGH, AND OROGRAPHIC LIFT FROM NORTHWESTERLY FLOW. AS
A RESULT OF THE OROGRAPHICS, THE NORTHERN MOUNTAINS ARE FAVORED TO
RECEIVE THE HIGHEST SNOWFALL AMOUNTS. HOWEVER, THESE HIGHEST
FORECASTED AMOUNTS ARE RELATIVELY UNIMPRESSIVE, CURRENTLY FORECASTED
TO BE JUST A FEW INCHES AT MOST. THE LIMITED SNOW TOTALS RESULT FROM
A LACK OF ATMOSPHERIC MOISTURE AVAILABLE. THE MAXIMUM PWAT ANOMALIES
FALL AT 60-70% OF NORMAL SUNDAY NIGHT INTO MONDAY, AND DROP TO BELOW
20% OF NORMAL MONDAY NIGHT. BY MONDAY EVENING ANY SNOW FROM THIS
EVENT IS EXPECTED TO COME TO AN END AS DRY AIR MOVES IN, AND THE
SHORTWAVE TROUGH PASSES OUT OF OUR REGION. THE DRY WEATHER THAT
BEGINS MONDAY NIGHT IS GENERALLY EXPECTED TO PERSIST THROUGH THE
LONG TERM.
THE MAIN CONCERN OF THE LONG TERM IS WELL BELOW NORMAL TEMPERATURES.
A VERY COLD ARCTIC AIRMASS IS ANTICIPATED TO IMPACT OUR AREA OVER
THE COMING DAYS. STRONG COLD AIR ADVECTION ON MONDAY WILL ALLOW FOR
TEMPERATURES TO BE 10 TO 25 DEGREES BELOW NORMAL ACROSS THE CWA ON
MONDAY AND TUESDAY. THE AREAS OF GREATEST CONCERN ARE THE UPPER
YAMPA RIVER BASIN AND GUNNISON VALLEY WHERE OVERNIGHT LOWS MONDAY
INTO TUESDAY COULD DROP TO 35 BELOW AND 40 BELOW RESPECTIVELY. AN
EXTREME COLD WATCH IS IN PLACE FOR THESE TWO LOCATIONS MONDAY
EVENING THROUGH TUESDAY MORNING. BY WEDNESDAY TEMPERATURES BEGIN TO
CLIMB BACK TOWARDS NORMAL, BUT MOST OF OUR AREA WON'T RETURN TO NEAR
NORMAL UNTIL FRIDAY.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 422 PM MST SAT JAN 18 2025
GUSTY NORTHERLY TO NORTHWESTERLY WINDS WILL CONTINUE THROUGH
THE NEXT 3-6 HOURS ACROSS THE REGION, BEFORE DIMINISHING AND
BECOMING LIGHT AND TERRAIN DRIVEN. LIGHT SNOW SHOWERS WILL
LINGER THROUGH SUNSET BEFORE CLEARING OVERNIGHT TONIGHT. CLEAR
SKIES TONIGHT WILL GIVE WAY TO INCREASING MID LEVEL CLOUDS
TOMORROW AFTERNOON. VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT
24 HOURS.
GJT WATCHES/WARNINGS/ADVISORIES
CO...WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR
COZ004-010-013-018.
COLD WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM MST SUNDAY
FOR COZ005.
EXTREME COLD WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR COZ005-014.
COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 11 AM MST
SUNDAY FOR COZ014.
COLD WEATHER ADVISORY FROM 10 PM SUNDAY TO 11 AM MST MONDAY
FOR COZ014.
WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ021-022.
UT...NONE.
SHORT TERM...NL
LONG TERM...GF
AVIATION...TGJT
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