698
FXUS65 KBOU 290606
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1206 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.
- A COUPLE OF STRONG STORMS COULD PRODUCE LOCALIZED FLASH
FLOODING, PARTICULARLY ALONG THE I-25 CORRIDOR.
- DRYING OUT AGAIN LATER IN THE WEEK. HEAT RETURNS BY THE
WEEKEND.
DISCUSSION /THROUGH TUESDAY/
ISSUED AT 1228 PM MDT TUE JUL 28 2026
GOES-18 SATELLITE DATA EARLY THIS AFTERNOON SHOW THAT ROBUST
CONVECTIVE INITIATION IS ONGOING ACROSS THE FRONT RANGE FOOTHILLS.
RADAR ESTIMATES AND PRECIPITATION GAUGES SUGGEST THAT SOME OF
THESE INITIAL STORMS HAVE STILL BEEN EFFICIENT RAINFALL PRODUCERS
ACROSS THE FOOTHILLS... MEANING THAT BURN AREA FLASH FLOODING IS
STILL A CONCERN THIS AFTERNOON.
HOWEVER, MUCH LIKE THE PAST SEVERAL DAYS... INITIAL CONVECTION
HAS STRUGGLED ONCE MAKING IT INTO THE URBAN CORRIDOR. WHY IS THIS?
THERE ARE SEVERAL POSSIBLE EXPLANATIONS. DESPITE A RELATIVELY
FAVORABLE ENVIRONMENT (T/TD OF 90/57 AT DEN), ACARS SOUNDINGS
STILL MAINTAIN A SUBTLE STABLE LAYER BETWEEN ROUGHLY 750-675 MB.
WHILE THERE'S STILL 1500-2000 J/KG MLCAPE IN THAT SOUNDING THERE'S
ALSO A RELATIVELY DEEP, WEAKLY BUOYANT REGION ABOVE THE LFC THAT
WOULD BE PRONE TO SOME ENTRAINMENT. WITH LITTLE/NO SYNOPTIC
ASCENT THROUGH THIS LAYER, IT WOULD LIKELY TAKE LARGER, MATURE
UPDRAFTS TO OVERCOME THIS. IT'S POSSIBLE ADDITIONAL CI ATTEMPTS
ACROSS THE FOOTHILLS WILL LEAD TO MORE SUSTAINED CONVECTION ACROSS
THE DENVER METRO, BUT IT APPEARS MORE LIKELY THAT OUR FAVORED
TERRAIN (NORTHERN FRONT RANGE AND PALMER DIVIDE) WILL SEE THE
BULK OF THE RAINFALL THIS AFTERNOON, WITH GRADUAL UPSCALE GROWTH
TOWARDS EAST OF THE I-25 CORRIDOR LATER THIS AFTERNOON AND
EVENING.
AS THAT CLUSTER OF CONVECTION SHIFTS EASTWARD, THE INCREASED
PRECIPITABLE WATER AND DEEPER WARM CLOUD LAYER DEPTHS WOULD FAVOR
THE POTENTIAL FOR SOME BRIEF BUT RATHER HEAVY RAINFALL RATES THIS
EVENING. RECENT REFS 3HR PMM QPF HINTS AT AS MUCH AS 3-5" OF
RAINFALL THIS EVENING IN WASHINGTON COUNTY... WITH BROAD SUPPORT
FROM TODAY'S HREF MEMBERS AS WELL. I SAW NO REASON TO ADJUST THE
EXISTING FLOOD WATCH ACROSS THE PLAINS, WHICH WILL REMAIN IN
EFFECT FROM 3-10 PM. AS THE MIDNIGHT SHIFT NOTED, THERE IS STILL A
SLIM POSSIBILITY THAT THIS CLUSTER OF STORMS EVENTUALLY SENDS SOME
OUTFLOW BACK TOWARDS THE METRO, WHICH WOULD PROVIDE ANOTHER
OPPORTUNITY FOR SOME SHOWERS/STORMS THAT WOULD BE CAPABLE OF
PRODUCING SOME HEAVY RAIN.
WEDNESDAY LOOKS TO BE THE LAST DAY OF WELL ABOVE NORMAL MOISTURE,
THOUGH SIMILAR CONCERNS REMAIN ABOUT THE COVERAGE OF STORMS ACROSS
THE REGION. OVERALL WE EXPECT A FAIRLY SIMILAR CONVECTIVE SETUP
COMPARED TO TODAY, WITH PERHAPS A BIT MORE COVERAGE ALONG/WEST OF
I-25. STORM CHANCES WILL BE DICTATED BY THE AMOUNT OF MOISTURE
RETURN TONIGHT/TOMORROW MORNING. ASSUMING WE DO SEE LOW/MID 60S
DEW POINTS ACROSS THE URBAN CORRIDOR TOMORROW MORNING, THERE WOULD
BE SOME HEAVY RAIN POTENTIAL ONCE AGAIN.
THE LATTER HALF OF THE WEEK WILL FEATURE A QUICK DRYING TREND,
WITH WARMER TEMPERATURES LIKELY RETURNING BY THE WEEKEND. CHANCES
FOR SHOWERS/STORMS WILL CONTINUE FOR THURSDAY BUT SHOULD QUICKLY
DIMINISH BY SATURDAY OR SUNDAY AS A 600 DAM RIDGE AT 500MB
DEVELOPS NEAR THE FOUR CORNERS REGION. GUIDANCE HINTS THAT WE
COULD SEE A RETURN OF UPPER 90S/LOW 100S BY THE END OF THE
WEEKEND, WHICH THEN PERSIST THROUGH EARLY NEXT WEEK.
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...HIRIS
AVIATION...MAI
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