616
FXUS65 KGJT 260000
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
600 PM MDT MON AUG 25 2025
KEY MESSAGES
- WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THIS AFTERNOON, WITH HEAVY RAIN AND FREQUENT LIGHTNING THE
MAIN CONCERNS. STRONGER STORMS COULD PRODUCE HAIL.
- THERE IS INCREASED CONCERN FOR FLASH FLOODING AND DEBRIS FLOWS
IN SENSITIVE AREAS, ESPECIALLY OVER RECENT BURN SCARS.
- WIDESPREAD PRECIPITATION AND BELOW NORMAL TEMPERATURES
CONTINUE THROUGH THE SEVEN DAY FORECAST.
SHORT TERM /THROUGH TUESDAY/
ISSUED AT 343 PM MDT MON AUG 25 2025
ACTIVE WEATHER THIS MORNING BROUGHT UP TO A FEW TENTHS OF RAIN
TO AREAS ALONG AND JUST NORTH OF I-70, INCLUDING THE LEE FIRE
BURN SCAR WHERE FLASH FLOODING AGAIN BECAME A CONCERN. CLEARING
IN CLOUD COVER QUICKLY TOOK OVER, WHICH HAS HELPED TO LIMIT
CONVECTIVE INHIBITION. AS OF THE 18Z SOUNDING, SOME STABILITY
REMAINED TO BE OVERCOME, BUT AS EVIDENT BY SOME STRONGER
CONVECTION BEGINNING TO POP OVER THE CWA, HIGHER INTENSITY
STORMS MAY BECOME MORE FREQUENT OVER THE COMING HOUR OR TWO.
FREQUENT LIGHTNING, STRONG OUTFLOW GUSTS UP TO 40 MPH, AND HAIL
POTENTIALLY REACHING AN INCH WILL ALL BE POSSIBLE IN THESE
STRONGER STORMS. LOCALIZED HEAVIER RAINFALL MAY ALSO PROMPT MORE
FLASH FLOODING CONCERNS, INCLUDING DEBRIS FLOWS NEAR BURN
SCARS, AS WE HAVE SEEN OVER THE PAST COUPLE DAYS. STORMS WILL
LIKELY TRANSITION INTO A STRATIFORM MODE LATER IN THE EVENING.
THE MOISTURE PLUME GETS REINVIGORATED EARLY TUESDAY MORNING AND
THROUGH THE AFTERNOON AS YET ANOTHER SHORTWAVE ROTATES AROUND
THE HIGH WHICH, AT THAT POINT, WILL BE CENTERED NEAR TEXAS.
PWAT'S WILL SHOOT BACK UP TO 175-200% OF NORMAL, WHICH WILL BE
OVER THE 90TH PERCENTILE FOR THIS TIME OF THE YEAR, FAVORING
SOUTHWESTERN COLORADO AND THE SAN JUANS DURING THE MORNING
BEFORE THE STRONGEST POOL OF MOISTURE ADVECTS NORTHWARDS THROUGH
THE AFTERNOON. THIS CARRIES WITH IT A QUICK RISE IN POP'S
BEFORE ACTIVITY DECLINES LATER IN THE WEEK.
THE MOST RECENT NBM RUN FOR TUESDAY DROPPED OVERNIGHT CLOUD
COVER AND RAISED EARLY MORNING CLOUD COVER. SHOULD THIS CONTINUE
TO BE THE TREND, WE COULD BE LOOKING AT AN ENVIRONMENT MORE
SUITABLE FOR STRATIFORM RAINFALL AS OPPOSED TO STRONGER, MORE
LOCALIZED CONVECTION, ESPECIALLY AROUND THE SAN JUANS. THIS
WOULD GIVE A BETTER OPPORTUNITY FOR SOOTHING FIRE AND DROUGHT
CONCERNS WHILE HOPEFULLY LIMITING FLASH FLOODING POTENTIAL.
CAM'S DO SEEM TO LEAN MORE TOWARDS ISOLATED OR SCATTED
CONVECTIVE-TYPE STORMS NORTH OF I- 70 LATE IN THE AFTERNOON, BUT
EVEN THESE COULD QUICKLY TRANSITION INTO A STRATIFORM MODE
SHOULD WE LACK MUCH DAYTIME HEATING. REGARDLESS, THE COMBINATION
OF NUMEROUS MUD AND ROCK SLIDES THE PAST COUPLE DAYS, THE
EXPECTED DURATION OF THESE STORMS, AND THE MUCH MORE SATURATED
SOILS FROM RECENT RAINFALL IS SETTING THE STAGE FOR A GREATER
FLASH FLOOD RISK TOMORROW THAN WE HAVE SEEN OVER THE PAST FEW
DAYS. THE RECENT TREND TOWARDS LESSER INSTABILITY FROM LACKING
DAYTIME HEATING AND THE RESULTING LEAN TOWARDS STRATIFORM-TYPE
STORMS STILL BRINGS FORTH SOME UNCERTAINTY. HOWEVER, IT IS STILL
IMPERATIVE TO STAY WEATHER-AWARE AND UP-TO-DATE WITH THE LATEST
GUIDANCE ON THIS STORM EVENT. THE MORNING FORECAST DISCUSSION
WILL PROVIDE MORE CLARITY ON THE EXPECTATION FOR TOMORROW'S
STORMS AS WE GET A BETTER IDEA FOR HOW CLOUD COVER IS EVOLVING.
LONG TERM /TUESDAY NIGHT THROUGH MONDAY/
ISSUED AT 343 PM MDT MON AUG 25 2025
A LOW AMPLITUDE UPPER-LEVEL RIDGE CENTERED OVER COLORADO SETS
UP FOR THE LATTER HALF OF THE WEEK. THIS PUTS EASTERN UTAH AND
WESTERN COLORADO IN A SOUTHWESTERLY FLOW PATTERN. A 50-60 KNOT
JET WILL KEEP MOISTURE ELEVATED THROUGH THE EXTENDED FORECAST,
BUT PWAT ANAMOLOUS BEGIN TO FALL FROM SOUTH TO NORTH ON
WEDNESDAY AS "DRIER" AIR BEGINS TO WORK IN. WITH PWAT ANOMALIES
FALLING FROM 175-200% TO 125-150% OF NORMAL, CONVECTION WILL
BECOME LESS WIDESPREAD AND FAVOR THE HIGHER TERRAIN. WITH THE
REGION ALREADY PRIMED FOR PRECIPITATION, CHANCES ARE HIGHER THAN
AFTERNOON STORMS COULD MOVE OFF THE TERRAIN AND INTO ADJACENT
VALLEYS (TYPICALLY TO THE NORTHEAST). STRONGER STORMS WILL
CONTINUE TO BE CAPABLE OF PRODUCING FREQUENT LIGHTNING AND BURN
SCAR FLASH FLOODING, BUT THE FREQUENCY IN WHICH THIS OCCURS WILL
TREND DOWNWARD INTO THE WEEKEND.
TEMPERATURES REMAIN AT OR BELOW SEASONAL NORMALS THROUGH THE
SEVEN- DAY FORECAST AND WILL BE HIGHLY DEPENDENT ON HOW MUCH
CLOUD COVER THERE IS EACH DAY. IN GENERAL, WE'LL SEE A DECREASE
IN CLOUD COVER HEADING INTO THE WEEKEND SO TEMPERATURES WILL
WARM A HANDFUL OF DEGREES IN RETURN.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 543 PM MDT MON AUG 25 2025
SHOWERS AND THUNDERSTORMS WILL CONTINUE MOSTLY ON THE TERRAIN
ALONG AND SOUTH OF THE I-70 CORRIDOR FOR THE NEXT 3-6 HOURS.
A FEW OF THESE STORMS WILL MOVE INTO THE VALLEYS WITH A CHANCE
FOR IMPACTS ON THE TAF SITES IN THESE AREAS. LOOK FOR LIGHT
TERRAIN DRIVEN WINDS UNDER SCATTERED TO BROKEN MID LEVEL CLOUDS
AND A FEW LINGERING SHOWERS THROUGH THE OVERNIGHT. SHOWERS AND
THUNDERSTORMS WILL REDEVELOP OVER SOUTHEASTERN UTAH AND
SOUTHWESTERN COLORADO AFTER 15Z, BECOMING WIDESPREAD ACROSS THE
REGION BY 20Z. PRIMARY RISKS WILL BE LIGHTNING AND BRIEF PERIODS
OF HEAVY RAIN PRODUCING MVFR TO IFR CONDITIONS BELOW ILS
BREAKPOINTS AT KASE, KEGE AND KRIL.
HYDROLOGY
ISSUED AT 343 PM MDT MON AUG 25 2025
FLASH FLOODING AND DEBRIS FLOWS OVER BURN SCARS CONTINUES TO BE
A PROMINENT CONCERN AS ANOMALOUSLY HIGH MOISTURE MAKES ITS WAY
THROUGH THE REGION. NON-BURN SCAR RELATED MUD AND ROCK SLIDES
HAVE ALSO BEEN OBSERVED OVER THE PAST COUPLE DAYS AS A RESULT OF
THE MULTIPLE DAYS OF RAINFALL. CAM'S ARE SUGGESTING WE ARE IN
STORE FOR ANOTHER JUICY DAY TOMORROW WITH STORMS GETTING GOING
EARLY IN THE MORNING. AS A RESULT, A FLASH FLOOD WATCH HAS BEEN
ISSUED FOR PORTIONS OF SOUTHEASTERN UTAH AND MUCH OF
WESTERN COLORADO.
GJT WATCHES/WARNINGS/ADVISORIES
CO...FLOOD WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
COZ003-006>014-017>023.
UT...FLOOD WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING FOR
UTZ022-028-029.
SHORT TERM...BW
LONG TERM...KAA
AVIATION...DB
HYDROLOGY...BW
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