226  
FXUS65 KBOU 200619  
AFDBOU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DENVER/BOULDER CO  
1219 AM MDT SUN OCT 20 2024  
   
KEY MESSAGES
 
 
 
- SCATTERED RAIN/SNOW SHOWERS OVER THE MOUNTAINS SUNDAY AFTERNOON.  
ANY RAIN OR SNOWFALL WILL BE VERY LIGHT.  
 
- DRY WITH ABOVE NORMAL TEMPERATURES TUESDAY INTO NEXT WEEKEND.  
 

 
   
UPDATE
 
 
ISSUED AT 821 PM MDT SAT OCT 19 2024  
 
THE MAIN FORECAST CONCERN IS THE COVERAGE OF THE FOG AND LOW  
CLOUDS TONIGHT. GREELEY IS ALREADY REPORTING 3 MILE VISIBILITY AND  
MIST AND NIGHTTIME MICROPHYSICS SHOWS UPSLOPE FLOW HAS CREATED  
LOW CLOUDS AND FOG OVER NORTHERN WELD COUNTY. WITH HIGH RELATIVE  
HUMIDITY AND LIGHT UPSLOPE FLOW, THE LOW CLOUDS AND FOG WILL  
EXPAND TONIGHT. FOG WAS MOVED UP IN THE FORECAST AND EXTENDED IN  
COVERAGE TO INCLUDE MOST OF THE I-25 CORRIDOR NORTH OF DOWNTOWN  
DENVER AND ALL OF WELD COUNTY. OTHERWISE, THERE MAY BE A FEW LIGHT  
SHOWERS IN LINCOLN COUNTY BUT THE REST OF THE AREA SHOULD REMAIN  
DRY TONIGHT.  
 

 
   
SHORT TERM /THROUGH SUNDAY/
 
 
ISSUED AT 153 PM MDT SAT OCT 19 2024  
 
UPPER LEVEL LOW WILL CONTINUE TO SPIN OVER ARIZONA THROUGH  
TONIGHT AND SUNDAY MORNING. IT FINALLY BEGINS TO LIFT  
NORTHEASTWARD DURING THE AFTERNOON, MAKING IT TO THE FOUR CORNERS  
AROUND 00Z MONDAY. NEARLY ALL OF THE PRECIPITATION ASSOCIATED WITH  
THIS SYSTEM WILL REMAIN OVER SOUTHERN COLORADO AND SOUTHWARDS. A  
FEW WEAK SHOWERS MAY STRAY FAR ENOUGH NORTH TO REACH PARK AND  
LINCOLN COUNTIES THROUGH THIS EVENING ANY RAIN OR MOUNTAIN  
SNOWFALL WILL BE VERY LIGHT. LOW LEVELS STAY SOMEWHAT MOIST AND  
WITH SOME CLEARING, FOG WILL BE POSSIBLE, MAINLY OVER THE LOW  
LYING AREAS NORTH OF DENVER. DEW POINTS ARE RUNNING IN THE 40S  
OVER NORTHEAST COLORADO. THIS HELP KEEP TEMPERATURES FROM COOLING  
MUCH OVERNIGHT WITH LOWS MAINLY IN THE 40S ACROSS NORTHEAST  
COLORADO.  
 
ON SUNDAY, A SURFACE LOW FORMS OVER NORTH CENTRAL COLORADO. THIS  
WILL PRODUCE GUSTY SOUTH WINDS ACROSS THE EASTERN PLAINS. WHERE THE  
SOUTHERLY WINDS PREVAIL, HIGHS ARE EXPECTED TO REACH THE 70S. A  
DENVER CYCLONE WILL FORM AND BRING NORTHERLY WINDS TO THE NORTHWEST  
PART OF THE URBAN CORRIDOR. HERE, HIGHS WILL BE COOLER WITH READINGS  
IN THE UPPER 60S TO LOWER 70S. ONLY CHANCES FOR SHOWERS WILL BE OVER  
SOUTHERN PARTS OF PARK AND LINCOLN COUNTIES AND THEN ALSO OVER THE  
HIGHER TERRAIN SUNDAY AFTERNOON DUE TO A LITTLE AFTERNOON  
INSTABILITY.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/
 
 
ISSUED AT 153 PM MDT SAT OCT 19 2024  
 
MODELS SHOW THE UPPER CLOSED LOW TO GET RIGHT OVER THE FOUR  
CORNERS BY 00Z LATE SUNDAY AFTERNOON. NOW THE TRACK OF THIS  
FEATURE IS PROGGED TO MOVE DUE EASTERLY FROM THERE ACROSS SOUTHERN  
COLORADO INTO THE SOUTHEAST CORNER OF THE STATE BY 18Z MONDAY.  
THIS PATH PUTS SOME UPWARD SYNOPTIC SCALE ENERGY OVER THE CWA  
SUNDAY INTO MONDAY MORNING, WITH SUBSIDENCE FOR THE REST OF  
MONDAY. FLAT UPPER RIDGING MOVES INTO THE FORECAST AREA FOR MONDAY  
NIGHT THROUGH TUESDAY NIGHT WITH MODERATELY STRONG WEST-  
NORTHWESTERLY FLOW ALOFT.  
 
LOOKING AT MOISTURE, IT IS OKAY OVER THE MOUNTAINS, SUNDAY NIGHT  
INTO EARLY MONDAY WITH LIMITED MEASURABLE PRECIPITATION ACCORDING  
TO THE QPF FIELDS. FOR THE PLAINS, MOISTURE IS MORE LIMITED, WITH  
THE QPF FIELDS SHOWING EVEN LESS MEASURE RAINFALL AND MOSTLY OVER  
THE SOUTHERN HALF. THERE IS JUST SOME UPPER LEVEL MOISTURE PROGGED  
FOR MONDAY NIGHT THROUGH TUESDAY NIGHT, AND NOT ALL MUCH ANYWAY.  
WILL KEEP THE 30-60% POPS GOING IN THE MOUNTAINS, AND 0-30%S LATE  
SUNDAY NIGHT INTO MONDAY MORNING FOR THE PLAINS.  
 
THE THICKNESS GRIDS SHOW HIGHS AROUND 70 DEGREES ACROSS THE  
PLAINS MONDAY, WARMING INTO THE MID 70S ON TUESDAY.  
 
FOR THE LATER DAYS, WEDNESDAY THROUGH SATURDAY, UPPER RIDGING IS  
PROGGED OVER THE FORECAST AREA THROUGH FRIDAY, WITH SOME ZONAL  
FLOW ON SATURDAY. THE AIRMASS LOOKS TO BE DRY AND WARM ALL FOUR  
DAYS WITH TEMPERATURES WELL ABOVE THE SEASONAL NORMALS FOR ALL  
DAYS BUT WEDNESDAY. A WEAK COLD FRONT IS PROGGED FOR THE PLAINS  
LATE TUESDAY NIGHT/EARLY WEDNESDAY, SO HIGHS OVER THE PLAINS WILL  
BE AROUND 70 DEGREES IN MOST AREAS. SOME AREAS ACROSS THE PLAINS  
COULD REACH 80 DEGREES FOR HIGHS THURSDAY AND FRIDAY.  
 

 
   
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
 
 
ISSUED AT 1145 PM MDT SAT OCT 19 2024  
 
WINDS HAVE SETTLED INTO DRAINAGE AT ALL AIRPORTS TONIGHT. THE  
MAIN CONCERN FOR THE MORNING WILL BE IF FOG SPREADS SOUTH AND INTO  
THE DENVER AREA TAF SITES. THE LATEST GUIDANCE SEEMS TO BE  
BACKING OFF SLIGHTLY, HOLDING IT JUST NORTH OF DEN, BUT HAVE KEPT  
THE TEMPO GROUP AS THERE MAY STILL BE IMPACTS IN THE MORNING WITH  
NORTH/NORTHWESTERLY FLOW STILL EXPECTED. EXPECT IMPACTS TO  
DIMINISH BY 16/17Z. GUSTY SOUTHERLY WINDS ARE EXPECTED TO INCREASE  
FROM SOUTH AT APA AROUND 19Z AND SPREAD NORTH TO DEN AND BJC BY  
23Z. ONCE WINDS INCREASE, GUSTS BETWEEN 25-35KTS WILL BE POSSIBLE  
THROUGH THE TAF PERIOD.  
 

 
   
BOU WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
UPDATE...DANIELSON  
SHORT TERM...MEIER  
LONG TERM....RJK  
AVIATION...BONNER  
 
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