334
FXUS65 KBOU 260055
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
655 PM MDT MON AUG 25 2025
KEY MESSAGES
- CONTINUED ACTIVE PATTERN THROUGH THE NEXT SEVERAL DAYS, WITH
BELOW NORMAL TEMPERATURES LIKELY.
- THE MAJORITY OF DAYS WILL HAVE WIDESPREAD COVERAGE OF SHOWERS
AND STORMS ACROSS THE HIGHER TERRAIN AND SCATTERED COVERAGE
ACROSS THE LOWER ELEVATIONS.
- LOCALLY HEAVY RAINFALL POSSIBLE, INCLUDING SOME POTENTIAL FOR
BURN AREA FLASH FLOODING WITH ANY STORMS OVER THE NEXT FEW DAYS.
DISCUSSION /THROUGH MONDAY/
ISSUED AT 226 PM MDT MON AUG 25 2025
A WAVE OF SHOWERS AND STORMS IS MOVING ACROSS THE FOOTHILLS AND
ONTO THE I-25 CORRIDOR THIS AFTERNOON. WITH AMPLE MOISTURE FOR
COLORADO STANDARDS AND LONG, SKINNY CAPE PROFILES, THE SHOWERS
AND STORMS ARE PRODUCING EFFICIENT RAINFALL. WITH SLOW MOVING
STORMS, THIS MAY PROVIDE A FLASH FLOODING THREAT ESPECIALLY OVER
THE BURN AREAS. HOWEVER, SINCE IT WAS CLOUDY ALMOST THE ENTIRE DAY
AND LOW LEVEL TEMPERATURES DID NOT WARM UP VERY MUCH, THE
INSTABILITY IS QUITE LIMITED. MIXED-LAYER CAPE IS AROUND 500 J/KG
FOR MUCH OF THE AREA AND NO SEVERE STORMS ARE EXPECTED. IN
ADDITION, THE LACK OF VERY INTENSE UPDRAFTS/STORMS IS LIMITING THE
FLASH FLOODING THREAT AS WELL. OVERALL, THERE IS OPTIMISM THAT
THERE WILL BE GREAT COVERAGE OF SHOWERS AND STORMS WITHOUT THE
FLOODING RAINFALL.
TUESDAY WILL BEGIN IN A SIMILAR WAY TO TODAY. THERE WILL BE PATCHY
FOG ACROSS THE SOUTH PLATTER RIVER VALLEY AND SOME FOG COULD
DEVELOP OVER THE DENVER METRO. A SHORTWAVE TROUGH WILL ARRIVE MUCH
LATER IN THE AFTERNOON THAN MONDAY WHICH MEANS SHOWERS AND STORMS
WILL BE SLOWER TO DEVELOP. THE HIGHER TERRAIN WILL SEE STORMS
BEGIN IN THE EARLY AFTERNOON WITH 70-80 PERCENT COVERAGE. ACROSS
THE I-25 CORRIDOR AND EASTERN PLAINS, CONDITIONS WILL BE SOMEWHAT
STABLE. WHILE MODELS LIKE THE HRRR PRODUCE STRONG STORMS, THERE IS
SKEPTICISM DUE TO THE STABILITY AND A SOLUTION MORE LIKE THE NAM
NEST IS FAVORED. THAT IS, SHOWERS AND STORMS WEAKENING
SUBSTANTIALLY AS THEY HEAD OVER LOWER ELEVATIONS.
WEDNESDAY AND THURSDAY APPEAR TO BE WET WITH MORE INTENSE STORMS
THAN MONDAY AND TUESDAY. EACH DAY WILL HAVE A SHORTWAVE TROUGH
THAT WILL BE PROVIDING FORCING AS WELL AS DEEPENING A SURFACE LOW
PRESSURE SYSTEM OVER SOUTHEAST COLORADO. THIS WILL INCREASE THE
EASTERLY, UPSLOPE FLOW AND WILL KEEP THE HIGH MOISTURE VALUES IN
PLACE. IT REMAINS TO BE SEEN IF TEMPERATURES WILL ACTUALLY WARM UP
AS THE MODELS SUGGEST BUT IF TEMPERATURE DO REACH THE 80S ACROSS
THE PLAINS EACH DAY, THERE COULD BE STRONG TO SEVERE STORMS. WHAT
IS MORE LIKELY IS THESE STORMS WILL PRODUCE HEAVY RAINFALL WHICH
COULD LEAD TO FLASH FLOODING. POPS ARE GENERALLY IN THE 60-80%
RANGE FOR EACH DAY.
THERE WILL BE A SLIGHT DECREASE IN PRECIPITABLE WATER ON FRIDAY
AND SATURDAY WHICH WILL LEAD TO LESS COVERAGE OF STORMS.
SCATTERED SHOWERS AND STORMS ARE STILL EXPECTED WITH A FLASH FLOOD
THREAT.
THE WET PATTERN MAY END ON SUNDAY OR MONDAY AS DRIER AIR MOVES IN
WITH SUBSIDENT FLOW. A RIDGE ALOFT APPEARS IT MAY DEVELOP INTO
EARLY NEXT WEEK WITH WARMER AND DRIER WEATHER.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 651 PM MDT MON AUG 25 2025
SCATTERED SHOWERS WILL CONTINUE IN THE DENVER AREA THROUGH AT
LEAST 03Z, AND POSSIBLY THROUGH 06Z. THE CHANCE OF THUNDER IS NOW
LOW, BUT INSTRUMENT APPROACHES MAY STILL BE NEEDED DUE TO AREAS OF
LOW CLOUDS.
THERE IS UNCERTAINTY ABOUT LOW CLOUD/FOG DEVELOPMENT FOR TUESDAY
MORNING. AREAS OF IFR/LIFR CONDITIONS ARE POSSIBLE IF THERE IS
ENOUGH CLEARING. AT THIS TIME, THERE IS A 60% CHANCE OF IFR
CONDITIONS AT KBJC/KDEN AND 30% AT KAPA. LIFR CONDITIONS ARE
POSSIBLE, BUT DENSE FOG WITH VISIBILITIES BELOW A QUARTER MILE IS
NOT EXPECTED.
ANY IFR CEILINGS SHOULD BE GONE BY 16Z, THOUGH THERE COULD STILL
BE AREAS OF MVFR CEILINGS. THERE WILL LIKELY BE A PERIOD 18Z TO
21Z WITH A MINIMUM OF LOW CLOUDS, THEN SCATTERED SHOWERS AND
THUNDERSTORMS WILL REDEVELOP.
HYDROLOGY
ISSUED AT 226 PM MDT MON AUG 25 2025
PRECIPITABLE WATER VALUES WILL BE WELL ABOVE NORMAL TODAY AND
TUESDAY. STORMS THAT DEVELOP WILL BE SLOW MOVING AND WILL HAVE
EFFICIENT RAINFALL PROCESSES. THIS WILL LEAD TO A THREAT OF FLASH
FLOODING ESPECIALLY OVER THE BURN AREAS. HOWEVER, THERE WILL BE
LIMITED INSTABILITY EACH DAY SO THERE IS HOPE THAT STORMS WILL NOT
BE INTENSE ENOUGH TO PRODUCE MUCH FLOODING.
SIMILAR MOISTURE AND RAINFALL PROCESSES ARE EXPECTED WEDNESDAY AND
THURSDAY. HOWEVER, THERE WILL BE BETTER FORCING AND HIGHER
INSTABILITY VALUES EACH DAY. THEREFORE, THE THREAT OF FLASH
FLOODING WILL INCREASE AND A FLOOD WATCH FOR FLASH FLOODING MAY BE
NEEDED.
BOU WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...DANIELSON
AVIATION...GIMMESTAD
HYDROLOGY...DANIELSON
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