435
FXUS65 KBOU 231756
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1156 AM MDT FRI OCT 23 2026
KEY MESSAGES
- WARM, DRY, AND BREEZY ON FRIDAY.
- COOLER WEATHER RETURNS THIS WEEKEND WITH CHANCES FOR RAIN. AN
OVERALL DRYING TREND EMERGING FOR MOST OF THE DENVER METRO AND
I-25 CORRIDOR.
- A COOL START TO NEXT WEEK, BUT A WARMING AND DRYING TREND LIKELY
BY MID-WEEK.
DISCUSSION /THROUGH THURSDAY/
ISSUED AT 1125 PM MDT THU OCT 22 2026
A DEEP PLUME OF MOISTURE EXTENDS FROM SOUTH CENTRAL COLORADO INTO
WESTERN NEW MEXICO AT THE TIME OF THIS AFD, AND SIGNIFICANT
RAINFALL TOTALS HAVE BEEN REPORTED ACROSS MUCH OF SOUTHWEST AND
SOUTHERN COLORADO OVER THE PAST 24 HOURS. IN OUR FORECAST AREA,
THERE'S BEEN SOME SCATTERED SHOWERS ACROSS THE MOUNTAINS AND OVER
THE EASTERN PLAINS (MAINLY LINCOLN AND WASHINGTON COUNTIES),
THOUGH PRECIPITATION AMOUNTS HAVE BEEN VERY LIGHT SO FAR. GUIDANCE
DOES ATTEMPT TO PUSH SOME OF THAT MORE ORGANIZED PRECIPITATION
INTO OUR FORECAST AREA OVERNIGHT, BUT THE TERRAIN BLOCKING AND
DOWNSLOPE OFF THE FRONT RANGE WILL LIKELY PREVENT ANY MEANINGFUL
RAINFALL FROM FALLING. THE NAM IS THE ONLY REAL EXCEPTION TO THIS
BUT DOESN'T APPEAR TO BE A VERY REALISTIC SCENARIO. A FEW LIGHT
SHOWERS WILL CONTINUE AT TIMES OVERNIGHT WITH MOSTLY CLOUDY SKIES
ACROSS THE FORECAST AREA.
FRIDAY WILL LIKELY END UP AS THE WARMEST (AND BREEZIEST) DAY OF
THE WEEK, AS THE PRIMARY SHORTWAVE ASSOCIATED WITH THE TROUGH TO
OUR WEST WILL LIFT OFF TO THE NORTHWEST. THE FLOW ALOFT SHOULD
SHIFT TO A SOUTHWESTERLY DIRECTION, FINALLY SHUNTING THE DEEPER
MOISTURE PLUME OFF TO THE EAST OF THE STATE AND ADVECTING IN THE
MUCH DRIER AIRMASS CURRENTLY OVER ARIZONA. THERE WOULD STILL BE
JUST ENOUGH MOISTURE ALOFT TO SUPPORT A COUPLE VIRGA SHOWERS IN
OUR FORECAST AREA, BUT MOST OF THE DAY WILL FEATURE PARTLY CLOUDY
SKIES. MID-LEVEL TEMPERATURES WILL STILL BE WARM AND THE WEAK
SUBSIDENCE AND DOWNSLOPE SHOULD PROMOTE HIGHS IN THE MID 70S TO
MID 80S ACROSS MOST OF THE LOWER ELEVATIONS. A BROAD LEE TROUGH
EXTENDING FROM DENVER THROUGH EASTERN WYOMING WILL KEEP WINDS A
BIT LIGHTER FOR THE NORTHERN I-25 CORRIDOR, WHILE MOST OF THE
DENVER METRO AND EASTERN PLAINS SEE SOME GUSTS OF 30-40 MPH DURING
THE AFTERNOON HOURS. WHILE WE WILL SEE A DRYING TREND, RELATIVE
HUMIDITY VALUES SHOULD REMAIN HIGH ENOUGH TO AVOID ANY CRITICAL
FIRE WEATHER CONDITIONS DURING THE AFTERNOON HOURS.
SATURDAY WILL FEATURE QUITE THE CHANGE FROM THIS PERIOD OF WARMER
WEATHER. A COLD FRONT STILL LOOKS LIKELY TO ARRIVE JUST AFTER
SUNRISE ON SATURDAY MORNING, WITH STEADY NORTHEAST SURFACE WINDS
EXPECTED THROUGH THE DAY. AS MENTIONED IN NUMEROUS FORECAST
DISCUSSIONS PRIOR TO THIS ONE, A CUTOFF LOW IS EXPECTED TO DEVELOP
OVER THE DESERT SOUTHWEST (NEAR THE CA/AZ BORDER) AND LIFT INTO
SOUTHEAST UTAH BY LATE SATURDAY NIGHT. WE'LL SEE ANOTHER PERIOD OF
MOISTURE ADVECTION INTO THE AREA WITH STRONGER SOUTH-SOUTHWEST
FLOW REDEVELOPING DURING THE DAY, LEADING TO AN INCREASE IN CLOUD
COVER AND CHANCES FOR SHOWERS BY LATE SATURDAY AFTERNOON. GUIDANCE
CONTINUES TO HINT AT A NEAR-SURFACE DRY LAYER THAT WOULD PREVENT
SIGNIFICANT PRECIPITATION ACROSS MOST OF THE MOUNTAINS AND
ADJACENT PLAINS, WITH BETTER CHANCES FOR RAIN ACROSS FAR EASTERN
COLORADO IN THE BETTER WARM AIR ADVECTION/ISENTROPIC LIFT SATURDAY
EVENING/NIGHT.
THERE IS A BIT MORE UNCERTAINTY FOR SUNDAY, AS GUIDANCE BEGINS TO
SPLIT INTO TWO SCENARIOS. MOST OF THE EXTENDED RANGE CAMS AND
REGIONAL MODELS KEEP MOISTURE/STRATUS ACROSS THE FORECAST AREA,
WHILE SOME DETERMINISTIC GUIDANCE (ECMWF) ADVECTS A DRIER AIRMASS
BACK INTO THE REGION. THOSE DRIER SOLUTIONS ARE MUCH WARMER WITH
HIGHS BACK IN THE 60S... WHILE THE MOIST/STRATUS SOLUTIONS WOULD
KEEP HIGHS CLOSER TO 50F. THE CURRENT FORECAST IS A BIT OF A
COMPROMISE WITH A SLIGHT PREFERENCE TOWARDS THE COOLER SOLUTIONS
AT THIS TIME. THE UPPER LOW IS EXPECTED TO SHEAR OUT AS IT LIFTS
THROUGH OUR FORECAST AREA SUNDAY NIGHT, BUT THIS COULD PROVIDE
ANOTHER PERIOD OF WEAK ASCENT... AND GUIDANCE GENERALLY ATTEMPTS
TO PRODUCE SOME LIGHT RAIN AND SNOW SHOWERS OVER THE REGION SUNDAY
NIGHT INTO MONDAY MORNING.
MONDAY WILL BE COOL BUT GENERALLY DRY IN THE WAKE OF THE TROUGH,
WITH LIGHT FLOW ALOFT. THE FLOW SHOULD TURN SOUTHWESTERLY AND
BEGIN TO STRENGTHEN BY TUESDAY OR WEDNESDAY AHEAD OF THE NEXT
WESTERN CONUS TROUGH. THAT APPROACHING TROUGH COULD LEAD TO
ANOTHER PERIOD OF COOLER/UNSETTLED WEATHER ACROSS THE STATE BY
LATE NEXT WEEK OR NEXT WEEKEND... BUT THAT FALLS OUTSIDE OUR
CURRENT FORECAST PERIOD.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1144 AM MDT FRI OCT 23 2026
GUSTY SOUTH/SOUTHWESTERLY WINDS ARE PRESENT AT ALL THREE TAF SITES
EARLY THIS AFTERNOON. WINDS ARE EXPECTED TO INCREASE A BIT
FURTHER FOR THE MID AFTERNOON, WITH GUSTS AROUND 30 TO 35KTS.
WINDS WILL START TO WEAKEN AROUND 00Z, BUT WE COULD STILL SEE A
FEW LIGHTER GUSTS (AROUND 20KTS) STICK AROUND DEN UNTIL 02Z.
MODELS ARE STRUGGLING A BIT WITH THE WINDS LATE THIS EVENING AND
EARLY OVERNIGHT. WE COULD SEE LIGHT DRAINAGE WINDS, BUT WE COULD
ALSO SEE LIGHT AND VARIABLE WINDS AHEAD OF THE APPROACHING SYSTEM.
A COLD FRONT WILL MOVE THROUGH THE TAF SITES AROUND 15Z, BRINGING
STRONGER NORTHEAST WINDS AND LOWER CEILINGS. CIGS ARE FORECAST TO
DROP TO 6000FT OR BELOW AT DEN BY 17Z TOMORROW. RIGHT NOW, WE DO
EXPECT APA AND BJC TO REMAIN VFR THROUGH THE MORNING, BUT CEILINGS
WILL LOWER AS WE GO THROUGH THE MORNING AND INTO TOMORROW
AFTERNOON.
BOU WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HIRIS
AVIATION...AP
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