706  
FXUS65 KBOU 181723  
AFDBOU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DENVER/BOULDER CO  
1123 AM MDT FRI OCT 18 2024  
   
KEY MESSAGES
 
 
 
- MUCH COOLER TEMPERATURES TODAY AND SATURDAY.  
 
- PRECIPITATION IS LIKELY THIS EVENING INTO SATURDAY MORNING, WITH  
SNOW IN THE HIGHER MOUNTAINS AND RAIN BELOW 9,000 FT.  
 
- CHANCE OF RAIN (20-50%) SATURDAY AFTERNOON INTO SUNDAY...WITH  
SNOW IN THE MOUNTAINS. BEST CHANCES SOUTH OF I-70.  
 
- A FEW INCHES OF SNOW EXPECTED IN MOST OF THE MOUNTAINS, WITH  
HEAVIER TOTALS SOUTH OF I-70.  
 
- DRY AND WARMER FOR ALL THE FORECAST AREA MONDAY THROUGH  
THURSDAY.  
 

 
   
UPDATE
 
 
ISSUED AT 951 AM MDT FRI OCT 18 2024  
 
ONLY MINOR UPDATES TO TODAY'S FORECAST WERE NEEDED. THE AIR  
BEHIND THE FRONT IS COLD AS EXPECTED, AND TEMPERATURES ARE FALLING  
BEHIND WHAT WE HAD IN THE FORECAST SO FAR. THUS, HAVE DROPPED  
MAXT ACROSS THE PLAINS/I-25 CORRIDOR A FEW DEGREES TO MATCH  
EXPECTED TRENDS. CAMS REALLY GET THINGS GOING PRECIP-WISE LATER  
THIS AFTERNOON ACROSS THE HIGH COUNTRY, THEN SPREAD THE PRECIP  
NORTHEAST ACROSS THE PLAINS AND I-25 CORRIDOR AFTER 4 PM.  
CONVECTION IS THE PRIMARY DRIVER OF THE PRECIPITATION SO IT WILL  
PROBABLY BE HIT OR MISS, BUT SOME AREAS COULD SEE A FEW TENTHS OF  
RAIN UNDER THE BEST SHOWERS THIS AFTERNOON. SNOW LEVELS LOOK TO  
REMAIN HIGH THROUGH THIS EVENING, REMAINING ABOVE 9 KFT THROUGH 6  
PM, THEN DROPPING TO AROUND 8 KFT BY MIDNIGHT. SNOW ACROSS THE  
HIGHER ELEVATIONS SHOULD GET GOING THIS AFTERNOON TOO THOUGH  
TRAVEL IMPACTS ARE NOT ANTICIPATED UNTIL EARLY SATURDAY MORNING  
GIVEN THE HIGH SNOW LEVELS, AND EVEN THEN IT WOULD BE MOST LIKELY  
FROM I-70 SOUTH WHERE HEAVIER SNOW IS EXPECTED TO FALL. THE  
FORECAST WAS NUDGED IN THIS DIRECTION BUT OVERALL EVERYTHING LOOKS  
ON TRACK INTO TONIGHT.  
 

 
   
SHORT TERM /THROUGH TONIGHT/
 
 
ISSUED AT 350 AM MDT FRI OCT 18 2024  
 
CURRENTLY, RADAR SHOWS LIGHT 20-30 DBZ SHOWERS FOR PARTS OF THE HIGH  
COUNTRY THIS MORNING. ADDITIONALLY, A FEW METARS SHOW WINDS SHIFTING  
NORTH AS THE COLD FRONT ENTERS NORTHEASTERN COLORADO. A COOLER  
AIRMASS SHOULD BRING MUCH LOWER TEMPERATURES COMPARED TO YESTERDAY.  
BREAKS IN PARTLY CLOUDY SKIES FOR THE PLAINS WILL ALLOW SOME DAYTIME  
HEATING WHERE AFTERNOON HIGHS BETWEEN 53-66F ARE POSSIBLE ACROSS THE  
PLAINS. MOUNTAINS AND VALLEYS DROP TO 38-55 THIS AFTERNOON. AS THE  
UPPER LEVEL TROUGH DIGS DEEPER INTO WESTERN PORTIONS OF COLORADO, A  
PLUME OF MID-LEVEL MOISTURE WILL LEAD TO SCATTERED TO NUMEROUS  
SHOWERS OVER NORTHEASTERN COLORADO STARTING LATE AFTERNOON. WEAK  
INSTABILITY EXIST IN THE FOOTHILLS AND PLAINS THUS AN ISOLATED  
THUNDERSTORM OR TWO COULD OCCUR LATE AFTERNOON HOURS THROUGH EARLY  
EVENING BUT MAJORITY OF AREAS SHOULD RECEIVE RAINFALL THIS  
EVENING. TEMPERATURES SHOULD DROP QUICKLY WHERE A FEW MOUNTAIN  
AREAS TRANSITION TO SNOW. THIS UPDATE INCLUDES A SLIGHT DECREASE  
TO NBM QPF VALUES IN THE MOUNTAINS LEADING TO AN OVERALL DECREASE  
IN SNOWFALL AMOUNTS DUE TO A DELAY IN SHOWERS THIS MORNING.  
SNOWFALL TOTALS THROUGH TONIGHT SHOULD REMAIN 1-3 INCHES FOR AREAS  
ABOVE 9 THOUSAND FEET. ALSO NBM QPF FALLS IN AGREEMENT WITH  
MODELS FOR AREAS EAST OF THE DIVIDE COULD RECEIVE 0.10-0.40 INCHES  
OF RAINFALL OVERNIGHT WITH HIGHEST TOTALS ALONG THE PALMER DIVIDE  
AND LINCOLN COUNTY. THE UPPER LOW WILL STALL IN THE FOUR CORNERS  
PROVIDING CONSISTENT MOISTURE AND WEAK SYNOPTIC FORCING WHICH  
KEEPS SHOWERS MAINLY SOUTH AND ALONG I-70 AFTER MIDNIGHT TONIGHT.  
 

 
   
LONG TERM /SATURDAY THROUGH THURSDAY/
 
 
ISSUED AT 350 AM MDT FRI OCT 18 2024  
 
THE STATIONARY UPPER-LEVEL LOW POSITIONED OVER ARIZONA IS  
EXPECTED TO REMAIN IN PLACE THROUGH SATURDAY. AS DAYTIME HEATING  
PROGRESSES THROUGHOUT THE MORNING, SNOW SHOWERS OVER THE SOUTHWEST  
FRONT RANGE MOUNTAINS, AND MOSQUITO RANGE ARE EXPECTED TO  
TRANSITION TO RAIN AS SNOW LEVELS RAISE BACK UP TOWARDS 10,000  
FEET. TEMPERATURES ARE EXPECTED TO WARM INTO THE MID 50S FOR  
SATURDAY'S HIGH ACROSS THE PLAINS AND MOUNTAIN VALLEYS, PUTTING US  
ROUGHLY 5 TO 10 DEGREES BELOW NORMAL FOR A CHANGE. DUE TO OUR  
PROXIMITY TO THE LOW, WE WILL HAVE A CHANCE FOR LIGHT RAIN SHOWERS  
THROUGHOUT THE DAY, WITH LIGHT SNOW SHOWERS POSSIBLE ABOVE  
10,000'. BY EARLY SUNDAY MORNING, SNOW TOTALS ARE EXPECTED TO BE  
LESS THAN 1" BELOW 10,000 FEET, WITH THE EXCEPTION OF PARK COUNTY  
WHERE 1-4" WILL BE POSSIBLE DOWN TO 9,500 FEET. THE GREATEST  
ACCUMULATIONS ARE EXPECTED IN THE MOSQUITO RANGE ABOVE 11,000  
FEET, WHERE CLOSE TO A FOOT IS EXPECTED. TOTALS WILL DECREASE AS  
YOU MOVE NORTH ACROSS THE FRONT RANGE MOUNTAINS. SOMETIME SUNDAY,  
THE LOW IS EXPECTED TO LIFT NORTHEAST ACROSS COLORADO. AS IT  
TRAVERSES THE AREA, LIGHT PRECIPITATION CAN BE EXPECTED WITH  
LOCALIZED AREAS OF HEAVIER RAINFALL, MAINLY AHEAD OF THE VORTICITY  
MAX, THOUGH EXACT PLACEMENT OF THIS FEATURE IS UNCLEAR AT THIS  
TIME. THERE WILL BE ENOUGH MOISTURE WRAPPING AROUND THE BACKSIDE  
OF THE LOW TO BRING ANOTHER WAVE OF MOUNTAIN SNOW SHOWERS, THIS  
TIME MORE FOCUSED ON OUR NORTHERN MOUNTAIN RANGES, WITH SNOW  
LEVELS EXPECTED TO STAY ABOVE 9,000 FEET. LIGHT ACCUMULATIONS ARE  
EXPECTED WITH THE HIGHEST ELEVATIONS SEEING UP TO 3" OF ADDITIONAL  
SNOWFALL SUNDAY THROUGH MONDAY MORNING.  
 
BY MONDAY AFTERNOON, ABOVE NORMAL TEMPERATURES WILL RETURN WITH 70S  
EXPECTED ACROSS THE PLAINS. WARM AND DRY CONDITIONS ARE EXPECTED  
THROUGH THE WEEK AS RIDGING PERSISTS OVER THE WESTERN CONUS ONCE  
AGAIN.  
 

 
   
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
 
 
ISSUED AT 1123 AM MDT FRI OCT 18 2024  
 
MVFR TO POSSIBLY IFR CONDITIONS ARE EXPECTED LATER THIS AFTERNOON  
AND OVERNIGHT INTO SATURDAY AS MOIST UPSLOPE FLOW CONTINUES FOR  
THE NEXT 24 HOURS OR SO. WINDS IN GENERAL LOOK TO BE NORTH TO  
NORTHEAST THROUGH 12Z SATURDAY, AND IN THE 7-13KT RANGE. IN TERMS  
OF CIGS AND PRECIPITATION, THE FIRST ROUND OF RAIN SHOWERS SHOULD  
REACH THE TERMINALS AROUND 21 OR 22Z, DROPPING CIGS TO AROUND 010.  
AFTER 01Z CIGS SHOULD REMAIN AROUND THERE MUCH OF THE OVERNIGHT  
HOURS, ALONG WITH THE POTENTIAL FOR RAIN AT LEAST THROUGH 06Z BUT  
THEN MUCH LOWER CHANCES OUT AFTER THAT. HIGH RESOLUTION MODELS  
HAVE ANOTHER BATCH OF STRATIFORM RAIN MOVING NORTHWARD AROUND 12Z.  
AS IT STANDS NOW, APA HAS THE BEST SHOT OF A STEADY RAIN. THINK  
DIA AND BJC MIGHT BE TOO FAR NORTH FOR A STEADY RAIN SO WE HAVE  
KEPT THAT OUT OF THE TAF FOR NOW. FOR THE MOST PART, THE LOW CIGS  
SHOULD BE THE BIGGEST IMPACT WITH OR WITHOUT THE RAIN.  
 
BY MIDDAY SATURDAY THE LOW CLOUDS SCATTER OUT AND WINDS LOOK TO  
TURN TO THE EAST AND SOUTHEAST AT UNDER 12 KTS. HOWEVER, THE CIGS  
STILL MAY REMAIN IN THE MVFR RANGE. THERE ARE ISOLATED CHANCES OF  
RAIN SHOWERS IN THE AFTERNOON BUT TOO LOW TO MENTION IN THE TAF.  
 
THE FINAL THING TO MENTION IS THE POSSIBILITY OF FOG. WITH MOIST  
NORTH WINDS, LOW CLOUDS AND FOG SHOULD DEVELOP OVER THE PALMER  
DIVIDE SOUTH OF APA. THE FOG WILL BE NEAR OR PERHAPS OVER APA  
AFTER 06Z, SO FOR NOW WE ARE HANDLING WITH A TEMPO GROUP. IF/WHEN  
IT RAINS AT APA, THAT SHOULD REMOVE THE FOG AFTER 12Z FOR SURE,  
AND CHANGES IN THE WINDS/MOISTURE AROUND THAT TIME COULD ALSO  
ELIMINATE THE FOG. MODELS HINT ON THE FOG GETTING CLOSE TO DEN BUT  
THIS ISN'T A TYPICAL FOG PATTERN AT DEN SO FOR NOW AM KEEPING ANY  
MENTION OF IT OUT OF DEN'S TAF.  
 

 
   
BOU WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
UPDATE...SCHLATTER  
SHORT TERM...AD  
LONG TERM...BONNER  
AVIATION...SCHLATTER  
 
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