080
FXUS65 KBOU 241813
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1213 PM MDT THU JUL 24 2025
KEY MESSAGES
- SCATTERED THUNDERSTORMS RETURN THIS AFTERNOON AND EVENING.
- HEAVY RAINFALL EXPECTED WITH STRONGER THUNDERSTORMS - LOCALIZED
FLOODING WILL BE POSSIBLE. GREATEST THREAT WILL BE FOR BURN
SCARS, THE URBAN CORRIDOR, AND THE PLAINS.
- HOTTER AND DRIER THIS WEEKEND AND INTO EARLY NEXT WEEK.
UPDATE
ISSUED AT 207 AM MDT THU JUL 24 2025
LOW STRATUS HAS BEEN STEADILY GAINING GROUND OVER PORTIONS OF THE
URBAN CORRIDOR AND PLAINS EARLY THIS MORNING. IF CLEARING IS
LIMITED AND/OR SLOW THIS MORNING, IT COULD DELAY THE ONSET OF ANY
AFTERNOON CONVECTION, BUT THE FORECAST CONTINUES TO LEAN TOWARDS
AN EARLY ENOUGH EROSION OF LOW CLOUDS AND STABLE AIR AT LOWER
LEVELS. HIGH PWAT VALUES WILL PERSIST THROUGH THE DAY AND
CONTRIBUTE TO EFFICIENT RAIN RATES UNDER ANY STRONGER
THUNDERSTORMS. ANY FLOODING CONCERNS SHOULD REMAIN RATHER
LOCALIZED, ALTHOUGH WILL NEED TO WATCH FOR ANY HEAVY RAIN THAT'S
COINCIDENT WITH BULLSEYES FROM PRIOR DAYS.
ADDITIONALLY, THERE'S SLIGHT POTENTIAL FOR AN INCREASED INCURSION
OF SMOKE LATER THIS AFTERNOON STEMMING FROM THE DRAGON BRAVO FIRE
IN GRAND CANYON NP. THE BULK OF THE SMOKE WILL STAY CONFINED TO
THE WESTERN SLOPE THIS MORNING, BUT DAYTIME MIXING MAY ALLOW FOR
SOME DRIFTING INTO THE FRONT RANGE DURING THE LATTER HALF OF THE
DAY.
DISCUSSION /THROUGH WEDNESDAY/
ISSUED AT 137 PM MDT WED JUL 23 2025
TRICKY FORECAST FOR TODAY AND TONIGHT, SO WE WILL FOCUS ON THE SHORT
TERM IMPACTS AND HAZARDS IN THIS DISCUSSION. A COLD FRONT HAS
SUCCESSFULLY PASSED ACROSS THE PLAINS THIS MORNING, LEAVING A FAIRLY
DEEP LAYER OF NORTHERLY WINDS AND DEWPOINTS IN THE MID 50S TO MID
60S IN IT'S PATH. PWAT VALUES ARE EXPECTED TO BE IN THE 130% TO 150%
RANGE OF NORMAL (ACARS SOUNDINGS ALREADY SHOWING ~110% OF NORMAL
EARLY THIS AFTERNOON), WITH THE CO/WY BORDER, MOUNTAINS, AND PALMER
DIVIDE AREAS SHOWING THE HIGHEST VALUES. FORECAST SOUNDINGS SHOW
LONG AND SKINNY CAPE PROFILES WITH WINDS FROM THE LCL TO THE EL
LARGELY BETWEEN 5-25 KTS. THE MAIN CONCERNS FOR TODAY WILL BE WITH
SLOW MOVING STORMS CAPABLE OF PRODUCING HEAVY RAINFALL THAT COULD
CAUSE LOCALIZED FLOODING OVER PORTIONS OF THE FORECAST AREA. WE
ARE LOOKING STORMS CAPABLE OF PRODUCING 1-2" ACCUMULATIONS OVER
THE MOUNTAINS, 2-4" FOR THE PALMER, AND 1-3" FOR THE PLAINS
UNDERNEATH THE SLOWER MOVING STORMS. AFTER YESTERDAY'S STORMS
BRINGING ELEVATED SOIL SATURATION TO AREAS OF THE PALMER, AND THE
NORTHERLY WINDS PROVIDING UPSLOPE FLOW BEHIND THE FRONT, LEANING
TOWARDS THESE AREAS HAVING GREATER POTENTIAL FOR SOME FLOODING
UNDER TODAY'S STORMS. IF WINDS TURN SLIGHTLY MORE TO THE NE, THIS
WOULD RESULT IN MORE OF AN UPSLOPE COMPONENT DEVELOPING FOR OUR
SOUTHERN FOOTHILLS, BRINGING INCREASED FLOODING POTENTIAL HERE AS
WELL. ADDITIONALLY, WITH THE INCREASED MOISTURE PROFILE IN PLACE
TODAY, THE FLASH FLOOD THREAT WILL BE ELEVATED FOR OUR BURN SCARS,
ESPECIALLY FOR CAMERON PEAK AND ALEXANDER MOUNTAIN.
WE HELD OFF ON ISSUING A FLOOD WATCH DUE TO THE ABOVE UNCERTAINTY
AND THE SPARSER COVERAGE OF THE EXPECTED HEAVY RAINERS THIS
AFTERNOON AND EVENING. THE LACK OF A FLOOD WATCH DOES NOT MEAN
THAT FLOODING WON'T OCCUR, THERE ARE JUST TOO MANY UNCERTAINTIES
TO PINPOINT EXACTLY WHERE IT WILL OCCUR.
CURRENTLY, SPC MESOANALYSIS SHOWS MLCAPE VALUES BETWEEN 500 AND
1000 J/KG ACROSS THE FORECAST AREA, WITH 1500 TO 2000 J/KG
PORTRAYED IN OUR NORTHERN MOST CORNER. AS MENTIONED ABOVE, LIGHT
WINDS ARE IN PLACE TO THE EL, AND 0-6KM BULK SHEAR IS CURRENTLY
UNDER 20KTS, SO STORMS WILL HAVE DIFFICULTY BECOMING MORE
ORGANIZED IN THIS ENVIRONMENT. THERE IS ONE AREA WHERE 0-6 BULK
SHEAR IS CLOSER TO 30 KTS (ALONG THE WYOMING BORDER IN LARIMER
COUNTY), WHERE SOME STRONGER STORMS WILL BE POSSIBLE. OVERALL,
THERE WILL BE AN ISOLATED THREAT FOR SEVERE GUSTS AND HAIL FOR THE
LOWER ELEVATIONS THROUGH THE EVENING, WITH THE GREATEST POTENTIAL
BEING OVER THE NORTHERN CORNER WHERE INSTABILITY WILL BE
GREATEST.
THURSDAY WILL SEE SLIGHTLY DRIER CONDITIONS ACROSS THE FORECAST
AREA WITH ANOTHER DAY OF LIGHT WINDS UNDER UPPER LEVEL RIDGING.
HIGH TEMPERATURES ARE FORECAST TO REMAIN BELOW 90F FOR ONE MORE
DAY ACROSS THE LOWER ELEVATIONS. SHEAR WILL INCREASE SLIGHTLY,
COMPARED TO TODAY, AND THERE WILL BE ENOUGH INSTABILITY PRESENT
FOR SCATTERED TO NUMEROUS AFTERNOON SHOWERS AND STORMS TO DEVELOP
ACROSS THE FORECAST AREA, WITH A FEW HAVING SEVERE POTENTIAL ALONG
THE I-25 CORRIDOR AND EASTERN PLAINS. 500 MB TEMPERATURES WILL
COOL BY A FEW DEGREES OVER TODAY'S, MAKING FOR A SLIGHTLY BETTER
ENVIRONMENT FOR HAIL GROWTH THAN TODAY. STORMS WILL BE CAPABLE OF
PRODUCING HEAVY RAINFALL ONCE AGAIN, WITH THE HREF SHOWING 1-2"
ACCUMULATIONS POSSIBLE ACROSS THE FORECAST AREA.
THE LONG TERM FORECAST STILL LOOKS ON TRACK FOR THE HEAT TURNING
BACK ON UNDER A PERSISTENT RIDGE OVER THE SE US, AND DRIER
CONDITIONS RETURNING TO THE FORECAST AREA.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1140 AM MDT THU JUL 24 2025
SOUTHEASTERLY WINDS ARE IN PLACE FOR KDEN AND KAPA LATE THIS
MORNING WITH LIGHT AND VRB WINDS FOR KBJC. EXPECTING THESE WINDS
TO PERSIST UNTIL AFTERNOON CONVECTION BRINGS VRB AND GUSTY WINDS
TO ALL TAF LOCATIONS. CLOUD COVER HAS LIMITED SURFACE HEATING
ALONG THE MAJORITY OF THE URBAN CORRIDOR, KEEPING TEMPERATURES A
FEW DEGREES BELOW THE FORECAST. WITH ACARS SOUNDINGS SHOWING
PLENTY OF CIN REMAINING, HAVE PUSHED CONVECTION POTENTIAL BACK AN
HOUR AT KDEN AND KAPA. WITH ELEVATED MOISTURE STILL IN PLACE
TODAY, EXPECT POTENTIAL FOR SLOWER MOVING STORMS TO PRODUCE HEAVY
RAINFALL, WITH VISIBILITIES BRIEFLY DROPPING AS LOW AS ~1SM
(10-15% CHANCE) WHILE STORMS ARE OVERHEAD. GUSTY OUTFLOW WINDS
BETWEEN 25-35 KTS WILL ALSO BE POSSIBLE WITH THESE SHOWERS AND
STORMS. ONCE STABLE CONDITIONS SET IN BEHIND STORMS/SHOWERS,
DRAINAGE WINDS ARE EXPECTED FOR KDEN/KAPA, WITH LIGHT AND VRB
WINDS EXPECTED FOR KBJC.
FOR FRIDAY, WINDS SHOULD TRANSITION TO THE EAST BY LATE MORNING
WITH POTENTIAL FOR A DENVER CYCLONE TO FORM SOMEWHERE NORTH OF THE
TAF SITES. STILL SOME UNCERTAINTIES WITH AFTERNOON CONVECTION
POTENTIAL, BUT FORECAST SOUNDINGS SHOW ENOUGH POTENTIAL FOR HIGH-
BASED SHOWERS CAPABLE OF PRODUCING GUSTY OUTFLOWS BY LATE
AFTERNOON, SO HAVE INTRODUCED A PROB30 TO ACCOUNT FOR THIS
CONCERN.
BOU WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...RODRIGUEZ
DISCUSSION...BONNER
AVIATION...BONNER
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