884
FXUS65 KBOU 161755
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1155 AM MDT SUN AUG 16 2026
KEY MESSAGES
- SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED THIS AFTERNOON AND
EVENING. A FEW OF THEM COULD BECOME STRONG TO SEVERE, WITH
STRONG WINDS, LARGE HAIL, AND HEAVY RAINFALL.
- WARMING AND DRYING TREND FOR MONDAY AND TUESDAY.
DISCUSSION /THROUGH SATURDAY/
ISSUED AT 136 AM MDT SUN AUG 16 2026
AS OF 1:30AM, WE'RE STARTING TO SEE SOME PATCHY FOG DEVELOP OVER
PORTIONS OF LARIMER AND WELD COUNTIES, WITH AREAS OF LARAMIE
COUNTY JUST TO OUR NORTH DOWN TO 1/4 MILE VISIBILITY. FOG IS
EXPECTED TO DEVELOP FURTHER SOUTH IN THE NEXT FEW HOURS,
POTENTIALLY IMPACTING THE URBAN CORRIDOR, PORTIONS OF I-25, I-70
AND I-76. VISIBILITIES DOWN TO 1/4 MILE ARE EXPECTED FOR ISOLATED
AREAS. A DENSE FOG ADVISORY MAY BE NEEDED IF THE COVERAGE OF THE
1/4 MILE VISIBILITIES ARE GREAT ENOUGH. THE MOST LIKELY TIMING OF
FOG NEAR THE URBAN CORRIDOR WILL BE BETWEEN 4AM AND 8AM.
THE UPPER LEVEL HIGH, THAT WAS TO OUR SOUTHEAST, WILL START TO MOVE
WEST TODAY. THIS WILL PUT US IN MORE ZONAL FLOW ALOFT, WHICH WILL
BEGIN OUR DRYING TREND. PRECIPITABLE WATER VALUES TODAY WILL
DECREASE, BUT WILL REMAIN AROUND 100% TO 125% OF NORMAL. A WEAK
DISTURBANCE WILL MOVE THROUGH THE FLOW ALOFT TO OUR SOUTH, PROVIDING
THE BEST LIFT AROUND THE PALMER DIVIDE AND SOUTH. SURFACE WINDS WILL
BE MORE FROM THE SOUTHEAST TODAY. THE SE SURFACE WINDS WILL ALLOW
FOR SOME WEAK UPSLOPE FOR OUR NORTHERN COUNTIES NEAR THE CHEYENNE
RIDGE. WITH THE SLIGHTLY LOWER PWS AND LESS WIDESPREAD LIFT,
SHOWERS AND STORMS ARE EXPECTED TO BE LOWER IN COVERAGE TODAY
COMPARED TO THE PAST FEW DAYS. SCATTERED SHOWERS AND
THUNDERSTORMS WILL LIKELY FORM AROUND THE CHEYENNE RIDGE AND
PALMER DIVIDE AREAS TODAY, MOVING EAST/SOUTHEAST THROUGH THE
AFTERNOON AND EVENING. THE FLASH FLOODING THREAT WILL BE LOWER
TODAY, DUE TO THE DECREASE IN PWS, DECREASE IN COVERAGE, AND
INCREASE IN STORM MOTIONS. HOWEVER, WITH ALL THE RAIN WE'VE SEEN
LATELY THERE COULD STILL BE SOME LOCALIZED FLOODING CONCERNS DUE
TO THE MORE SATURATED SOILS AND LOWER FLASH FLOOD GUIDANCE. WE DO
HAVE A SLIGHT RISK FOR SEVERE WEATHER AGAIN THIS AFTERNOON. LOW
LEVEL LAPSE RATES WILL BE STEEP TODAY AND 0-6KM SHEAR WILL BE
SUFFICIENT FOR STRONG TO SEVERE STORMS TO DEVELOP (~30 TO 35
KTS). BUT THERE IS A POTENTIAL BUST FACTOR WITH THE SEVERE
WEATHER THREAT, DUE TO THE POSSIBILITY OF MORNING FOG AND LOW
CLOUDS STICKING AROUND LONGER THAN EXPECTED AND IMPACTING
INSTABILITY. STRONGER STORMS WILL HAVE THE CAPABILITY OF
PRODUCING LARGE HAIL, STRONG WINDS, AND HEAVY RAINFALL.
A WARMING AND DRYING TREND IS FORECAST FOR MONDAY AND TUESDAY. UPPER
LEVEL RIDGING WILL START TO BUILD TO OUR WEST AS THE UPPER LEVEL
HIGH SHIFTS MORE TOWARDS THE FOUR CORNERS REGION. TEMPERATURES ON
MONDAY WILL WARM CLOSER TO NORMAL WITH MUCH LOWER RAIN CHANCES. ON
TUESDAY, MODELS ARE STILL A BIT UP IN THE AIR, BUT A FEW OF THEM ARE
HINTING AT A WEAK COLD FRONT TUESDAY AFTERNOON AND EVENING MOVING
IN FROM THE NORTH. THE TIMING OF THIS FRONT WILL IMPACT HIGHS IN
OUR NORTHERN PLAINS COUNTIES FOR TUESDAY AND OUR PRECIP CHANCES
FOR TUESDAY. WE'LL SEE A BRIEF COOLING IN THE TEMPERATURES ON
WEDNESDAY BEHIND THAT FRONT, AND AN INCREASE IN RAIN CHANCES AS WE
SEE INCREASED MOISTURE BEHIND THE FRONT AND MAYBE SOME SURFACE
CONVERGENCE FROM THE STALLED BOUNDARY. BUT THEN UPPER LEVEL
RIDGING REALLY STARTS TO BUILD JUST TO THE WEST OF OUR AREA FOR
THURSDAY AND FRIDAY, BEFORE SHIFTING EAST OVER OUR AREA FOR THE
WEEKEND. HIGHS ARE FORECAST TO SIT IN THE MID 80S TO MID 90S FOR
THE PLAINS FOR THE END OF NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1136 AM MDT SUN AUG 16 2026
AS OF 1745Z, CUMULUS CLOUDS ARE STARTING TO BUILD IN THE
MOUNTAINS AND THE FOOTHILLS TO THE WEST OF THE THREE SITES WITH A
SCATTERED DECK PUSHING INTO KBJC. THERE IS STILL A CAP IN PLACE AS
SEEN ON ACARS SOUNDINGS AND RADAR IS JUST STARTING TO SHOW SOME
RETURNS IN PARK COUNTY. GIVEN THE FOG THAT WAS IN PLACE THIS
MORNING AS WELL AS THE CAP STILL IN PLACE, WE HAVE HELD OFF ON THE
PROB30 FROM STARTING UNTIL 22Z AT KDEN AND THEN LASTING UNTIL
ABOUT 3Z. GUSTY WINDS, LOWERING CEILINGS, AND HEAVY RAINFALL
(BRIEFLY LIMITING VISIBILITY) ARE POSSIBLE FROM ANY STORM THAT
PASSES NEAR OR DIRECTLY OVER THE TAF SITES. SOME CAMS ARE SHOWING
SHOWERS AND THUNDERSTORMS LINGERING A BIT AFTER 3Z, BUT CONFIDENCE
IS LOW IN THIS SCENARIO AT THIS TIME.
THERE IS ALSO SOME UNCERTAINTY ON THE WINDS TONIGHT. FOR NOW, WE
HAVE GONE AHEAD WITH AN E TO SE WIND THIS EVENING BEFORE WINDS
TURN TO DRAINAGE BY ABOUT 7Z. SEVERAL CAMS DEPICT OUTFLOW
BOUNDARIES FROM STORMS TO THE EAST MOVING THROUGH THE METRO EARLY
THIS EVENING POTENTIALLY AFFECTING KAPA AND KDEN. IF THIS WERE TO
OCCUR, WINDS COULD SHIFT MORE TO AN EAST OR NORTHEAST DIRECTION
AND BRIEFLY GUST TO AROUND 20 KTS.
FOR TOMORROW, WINDS WILL START TO TURN CLOCKWISE BEFORE SETTLING
ON A NORTHEAST DIRECTION EARLY IN THE AFTERNOON. MODEL SOUNDINGS
SHOW DCAPE VALUES REACHING UP TO 15,000 J/KG AND SOME MID-LEVEL
MOISTURE LINGERING. SO, WE EXPECT THE POSSIBILITY OF VIRGA
SHOWERS AND DRY MICROBURSTS STARTING AROUND 21Z AND LASTING
THROUGH THE EARLY EVENING (POTENTIALLY A BIT AFTER THE TAF
PERIOD). THESE COULD BRING GUSTY WINDS AND CEILINGS LOWERING TO
ABOUT 12,000 FT AGL WITH LITTLE TO NO RAINFALL EXPECTED. HAVE NOW
INCLUDED A PROB30 FOR THIS POSSIBILITY.
BOU WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...AP
AVIATION...MV
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