853
FXUS65 KBOU 290904
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
304 AM MDT WED JUL 29 2026
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS LIKELY ACROSS THE HIGH TERRAIN IN THE
LATE MORNING, SHIFTING TO THE PLAINS BY THE AFTERNOON.
- STRONG STORMS COULD PRODUCE LOCALIZED FLASH FLOODING,
PARTICULARLY FOR THE BURN SCAR AND AREAS ALONG AND EAST OF THE
I-25 CORRIDOR.
- DRYING OUT AGAIN LATER IN THE WEEK. HEAT RETURNS BY THE
WEEKEND.
DISCUSSION /THROUGH TUESDAY/
ISSUED AT 301 AM MDT WED JUL 29 2026
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS EXPECTED TODAY AS ABOVE
NORMAL MOISTURE REMAINS IN PLACE FOR ONE MORE DAY. MAIN CONCERN
CONTINUES TO BE LOCALIZED HEAVY RAINFALL PRODUCING FLASH
FLOODING, PARTICULARLY FOR BURN SCAR AREAS IN THE MOUNTAINS, AND
PORTIONS OF THE PLAINS. LET'S BREAK IT DOWN BELOW:
GUIDANCE CONTINUES TO FAVOR ABOVE NORMAL PRECIPITABLE WATER VALUES
>1", WHICH IS ABOVE THE 90TH PERCENTILE FOR THE DENVER AREA.
FORECAST SOUNDINGS SHOW TALL, THIN CAPE (A TYPICAL PROFILE FOR
MAXIMIZING PRECIPITATION EFFICIENCY) WITH A RELATIVELY MOIST
VERTICAL PROFILE AND A WARM CLOUD LAYER DEPTH OF 4-5,000 FT. THESE
INGREDIENTS COUPLED WITH EXPECTED SLOW STORM MOTION, WILL PROMOTE
HEAVY RAINFALL AND LOCALIZED FLASH FLOODING. A FLASH FLOOD WATCH WAS
CONSIDERED FOR PORTIONS OF THE PLAINS, INCLUDING THE I-25 CORRIDOR
AND ADJACENT AREAS EAST. HOWEVER, RECENT REFS 3HR LPMM QPF IS
NOWHERE NEAR AS ROBUST AS IT WAS FOR TUESDAY'S CONVECTION
(SUGGESTING 0.75"-1.25" ALONG THE URBAN CORRIDOR WITH THE STRONGEST
STORMS FOR TODAY). THE MOST LIKELY REASON FOR THIS IS DUE TO THE
LACK OF DECENT INSTABILITY COMPARED TO YESTERDAY, WITH MOST CAMS
INDICATING >1000 J/KG OF MLCAPE FOR THE URBAN CORRIDOR (BETTER
INSTABILITY FARTHER EAST). FOR THIS REASON, HAVE HELD OFF ON A WATCH
FOR NOW, BUT IF MODELS BEGIN CHANGING AND ALIGNING MORE WITH THE NAM
(THE MORE BULLISH MODEL FOR TODAY'S CONVECTION), THE NEXT FORECAST
PACKAGE MAY NEED ONE.
TIMING: WIDESPREAD CONVECTION IS EXPECTED TO BEGIN BY THE LATE
MORNING/EARLY AFTERNOON ACROSS THE HIGH TERRAIN, BEFORE SPILLING
ONTO THE PLAINS AND TREKKING EAST THROUGHOUT THE
AFTERNOON/EVENING. BEST CHANCE FOR THE URBAN CORRIDOR TO SEE
PRECIPITATION WILL BE 2/3 PM AND INTO THE LATE AFTERNOON. WHILE
COVERAGE IN SHOWERS/THUNDERSTORMS ARE EXPECTED TO BE GREATER TODAY
DUE TO BETTER MOISTURE RETURN, THAT DOES NOT MEAN THAT ALL AREAS
WILL SEE BENEFICIAL RAINFALL. STORMS WILL SHIFT INTO THE FAR
EASTERN PLAINS BY EARLY EVENING AND CONTINUE THROUGH 10/11 PMISH.
SOME GUIDANCE DOES FAVOR ADDITIONAL SCATTERED SHOWERS FOR THE HIGH
TERRAIN OVERNIGHT THURSDAY DUE TO AN UPPER LEVEL SHORTWAVE.
HOWEVER, COVERAGE WILL BE LIMITED.
MODELS CONTINUE TO FAVOR A DRYING TREND TOWARDS THE END OF THE WEEK,
WITH WARMER TEMPERATURES RETURNING BY THE WEEKEND. SCATTERED SHOWERS
AND THUNDERSTORMS ARE STILL POSSIBLE THURSDAY AND FRIDAY, HOWEVER
COVERAGE WILL BE LIMITED. THE UPPER LEVEL RIDGE IN THE SOUTHWESTERN
UNITED STATES WILL BEGIN TO RESTRENGTHEN, WITH 700MB TEMPERATURES
REACHING UP TO 20-22 DG C BY SUNDAY. ENSEMBLES FAVOR PORTIONS OF THE
PLAINS REACHING 100 F SUNDAY AND POSSIBLY MONDAY.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1147 PM MDT TUE JUL 28 2026
WINDS ARE CURRENTLY FROM THE SOUTHEAST AT DEN AND APA (NORTHWEST
AT BJC) AND WILL LIKELY CONTINUE FOR THE NEXT FEW HOURS BEFORE
DRAINAGE FLOW TAKES PLACE. IN THE MORNING, EXPECT LIGHT AND (<10
KTS) AND VRB WINDS. THERE COULD BE AREAS OF FOG IN THE MORNING
GIVEN HIGH DEWPOINTS, HOWEVER CONFIDENCE IS NOT HIGH (10-20%
CHANCE) SO HAVE DECIDED TO KEEP ANY MENTION OF IT OUT OF THE TAF
FOR NOW.
EXPECT A SIMILAR SETUP WITH SHOWERS AND THUNDERSTORMS FOR THE
AFTERNOON AS TUESDAY. CONVECTION WILL BEGIN IN THE MOUNTAINS BY
LATE MORNING/EARLY AFTERNOON, BEFORE SPILLING ONTO THE PLAINS BY
20Z-21Z. GUSTY OUTFLOW WINDS OF 40-45 KTS AND HEAVY RAIN REDUCING
VISIBILITY WILL BE THE MAIN CONCERNS. CAM TRENDS CONTINUE TO
INDICATE SCATTERED SHOWERS AFTER THE MAIN LINE OF CONVECTION IN
THE EVENING, SO HAVE KEPT THE PROB30 IN THE TAF.
BOU WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...MAI
AVIATION...MAI
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