733  
FXUS65 KGJT 131207  
AFDGJT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
507 AM MST THU FEB 13 2025  
   
KEY MESSAGES  
 
- AN ATMOSPHERIC RIVER WILL BRING PRECIPITATION INCLUDING SIGNIFICANT  
MOUNTAIN SNOW LATER TODAY THROUGH SATURDAY EVENING.  
 
- MODERATE TO HEAVY SNOW IS EXPECTED FOR MOST MOUNTAIN RANGES.  
TRAVEL MAY BE SIGNIFICANTLY IMPACTED TONIGHT AND TOMORROW  
ESPECIALLY ON MOUNTAIN PASSES.  
 
- SNOW LEVELS WILL VARY AROUND 5000 TO 7000 FEET, WHICH IS WHERE  
CONFIDENCE IN SNOW AMOUNTS IS LOW TO MEDIUM.  
 
- A SERIES OF STORMS IN NORTHWEST FLOW WILL BRING ADDITIONAL  
SNOWFALL TO THE AREA LATER THIS WEEKEND INTO EARLY NEXT WEEK.  
 
 
   
SHORT TERM /THROUGH FRIDAY/  
 
ISSUED AT 256 AM MST THU FEB 13 2025  
 
THE HIGHLY ANTICIPATED LOW PRESSURE SYSTEM IS CURRENTLY MAKING  
LANDFALL ALONG THE CALIFORNIA COAST. FLOW AHEAD OF THE SYSTEM HAS  
SHIFTED TO THE SOUTHWEST, WHICH WILL USHER IN WARMER TEMPERATURES  
AND EVENTUALLY MOISTURE. IN FACT, HIGHS WILL BE ABOUT 10 DEGREES  
WARMER THAN YESTERDAY DESPITE THE INCREASING CLOUDS. AS THE LOW  
PRESSURE MOVES INLAND TODAY IT WILL WEAKEN INTO AN ELONGATED TROUGH  
WITH A STRONG JET AT THE BASE. MOISTURE STEADILY INCREASES THROUGH  
OUT THE DAY WITH PEAK ADVECTION TAKING PLACE TONIGHT. PWAT VALUES  
ARE STILL ON TRACK TO REACH 200-300 PERCENT OF NORMAL, WHICH IS  
RATHER IMPRESSIVE. RAIN AND SNOW SHOWERS WILL DEVELOP AND SPREAD  
FROM WEST TO EAST LATE THIS AFTERNOON AND EARLY EVENING WITH A BULK  
OF THE PRECIPITATION OVERNIGHT.  
 
AS PREVIOUSLY MENTIONED THE TEMPERATURES MAKE THIS A COMPLICATED  
FORECAST. THERE IS SUBSTANTIAL DRY AIR AT THE SURFACE, WHICH  
MEANS WET BULB TEMPERATURES SUPPORT SNOW FOR MOST LOCATIONS.  
ALTHOUGH, SOME VALLEYS ARE GETTING INTO THE MID-UPPER 40S TODAY,  
SO THAT WOULD IMPLY RAIN. IN REALITY, THOSE LOCATIONS MAY NOT  
EVEN SEE PRECIPITATION REACH THE GROUND EARLY IN THIS STORM. AS  
PRECIPITATION SATURATES THE LOWER LEVELS IT WILL COOL THE  
ENVIRONMENT AND ALLOW SNOW WITH EXCEPTION OF PORTIONS OF  
SOUTHEAST UTAH. THE TRICKY PART IS THAT OVERNIGHT WARM ADVECTION  
WILL BE FIGHTING AGAINST THIS COOLING. THEREFORE SOME PLACES  
MAY START OUT AS SNOW THEN CHANGE OVER TO RAIN, WHICH LOOKS TO  
BE AROUND 5-6KFT. THE MOUNTAINS WILL NOT STRUGGLE WITH THIS  
PROBLEM AND SATURATE QUICKLY, SO MODERATE TO HEAVY SNOW IS  
EXPECTED SOON AFTER IT STARTS. THE MOISTURE WILL SPREAD ACROSS  
THE ENTIRE FORECAST AREA, BUT THE HIGHEST VALUES WILL BE IN AND  
AROUND THE SOUTHERN TWO THIRDS. THIS IS ALSO WHERE THE NOSE OF  
THE JET PASSES OVER, SO THERE COULD BE SOME ADDED FORCING TO GO  
ALONG WITH THE OROGRAPHICS. THE MOST IMPACTED CORRIDOR OUTSIDE  
OF THE MOUNTAINS WILL BE HIGHWAYS 160 AND 491 ESPECIALLY TONIGHT.  
 
TOMORROW WIDESPREAD MOUNTAIN SNOW WILL CONTINUE AS THE BROAD TROUGH  
PASSES OVER THE REGION. BY THE AFTERNOON THOUGH THE RATES MAY  
ACTUALLY DECREASE DUE TO THE MOSITURE ON THE DOWN TICK. SOME OF THE  
VALLEYS MAY ALSO SEE PRECIPITATION STOP OR LIGHTEN UP. ALSO, MODELS  
SHOW TEMPERATURES INCREASING THROUGH OUT THE DAY, WHICH MAY ALLOW  
FOR A CHANGE OVER FROM SNOW TO RAIN. ALL OF THE WATCH HAS BEEN  
UPGRADED TO EITHER WARNINGS AND ADVISORIES. ALSO, SOME OTHER ZONES  
HAVE BEEN ADDED TO SUITE OF HAZARDS.  
 
 
   
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/  
 
ISSUED AT 256 AM MST THU FEB 13 2025  
 
BY FRIDAY NIGHT SNOWFALL RATES DECREASE AS THE MOST ELEVATED  
MOISTURE FROM THE ATMOSPHERIC RIVER EXITS OUR AREA, AND UPPER-LEVEL  
SUPPORT WEAKENS. HOWEVER, LINGERING PWAT ANOMALIES OF AROUND 120-  
150% OF NORMAL, A PASSING LONGWAVE TROUGH, AND OROGRAPHIC LIFT FROM  
FLOW TRANSITIONING TO WEST TO NORTHWESTERLY WILL ALLOW FOR LIGHTER  
WIDESPREAD PRECIPITATION THROUGH SATURDAY. SNOWFALL IS EXPECTED IN  
AREAS OF HIGHER TERRAIN, BUT THERE IS UNCERTAINTY IN DETERMINING THE  
FORM OF PRECIPITATION VALLEYS WILL RECEIVE FRIDAY NIGHT. FLOW SHIFTS  
FROM WESTERLY TO NORTHWESTERLY FRIDAY NIGHT INTO SATURDAY MORNING,  
DROPPING TEMPERATURES AS COLDER AIR ADVECTS INTO THE REGION. THIS  
COULD ALLOW FOR A TRANSITION FROM RAIN TO A WINTRY MIX OR SNOW IN  
THE LOWER VALLEYS OVERNIGHT. WINTER STORM WARNINGS HAVE NOW BEEN  
ISSUED AS 1 TO 2 FEET OF SNOW IS EXPECTED ACROSS MOST MOUNTAIN  
RANGES, WITH LOCALLY HIGHER AMOUNTS POSSIBLE. HAZARDOUS TRAVEL  
CONDITIONS ARE ANTICIPATED THROUGH AT LEAST SATURDAY EVENING, SO BE  
SURE TO USE CAUTION IF TRAVELING.  
 
A BRIEF PAUSE IN SNOWFALL IS EXPECTED AFTER THE CONCLUSION OF THIS  
WINTER STORM LATE SATURDAY NIGHT, BUT LIGHT SNOW RETURNS TO THE  
NORTHERN MOUNTAINS DURING THE DAY SUNDAY. PWAT ANOMALIES AROUND 150%  
OF NORMAL AND NORTHWESTERLY FLOW WILL ALLOW FOR OROGRAPHICALLY  
FORCED SNOWFALL. ON MONDAY A WEAK PASSING DISTURBANCE COUPLED WITH  
SLIGHTLY ELEVATED ATMOSPHERIC MOISTURE SHOULD ALLOW FOR LIGHT  
SNOWFALL TO SPREAD ACROSS OUR REGIONS OF HIGHER TERRAIN THROUGH  
TUESDAY. THIS SECOND EVENT SEEMS TO BE LESS IMPACTFUL THAN THE STORM  
ENDING SATURDAY, BUT COULD STILL BRING SIGNIFICANT SNOWFALL,  
ESPECIALLY IN OUR NORTHERN AND CENTRAL MOUNTAINS.  
 
TEMPERATURES GENERALLY STAY NEAR NORMAL DURING THE FORECAST PERIOD,  
BUT SHOULD DROP SLIGHTLY OVER THE WEEKEND AS FLOW SHIFTS TO HAVE  
MORE OF A NORTHERLY COMPONENT. EARLY NEXT WEEK FLOW IS ANTICIPATED  
TO BRIEFLY TRANSITION TO ZONAL, WHICH SHOULD RAISE TEMPERATURES A  
BIT TO NEAR OR ABOVE NORMAL.  
 
 
   
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/  
 
ISSUED AT 451 AM MST THU FEB 13 2025  
 
THE TAF PERIOD BEGINS WITH QUIET WEATHER AND RELATIVELY CLEAR  
SKIES. AS THE DAY PROGRESSES SCT TO OVC CLOUD COVERAGE WILL  
MOVE IN FROM THE WEST. WIDESPREAD SNOWFALL BEGINS THIS  
AFTERNOON, IMPACTING MOST TAF SITES. CEILINGS AND VISBILITIES  
WILL DROP WITH THIS STORM, LIKELY IMPACTING FLIGHT CONDITIONS  
AND DROPPING CEILINGS BELOW ILS BREAKPOINTS FOR PROLONGED  
PERIODS. SNOW FROM THIS STORM IS ANTICIPATED TO CONTINUE THROUGH  
SATURDAY.  
 
 
   
GJT WATCHES/WARNINGS/ADVISORIES  
 
CO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST  
SATURDAY FOR COZ003-014.  
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST  
SATURDAY FOR COZ004-009-010-012-013-017>019.  
WINTER STORM WARNING FROM 6 AM FRIDAY TO 6 PM MST SATURDAY FOR  
COZ005.  
WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON MST FRIDAY  
FOR COZ021>023.  
UT...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST  
SATURDAY FOR UTZ023-025.  
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST  
SATURDAY FOR UTZ028.  
 
 
 
 
 
SHORT TERM...KJS  
LONG TERM...GF  
AVIATION...TGJT  
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