890
FXUS65 KBOU 201712
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1112 AM MDT SUN SEP 20 2026
KEY MESSAGES
- A FEW MORNING SHOWERS/STORMS ACROSS OUR NORTHERN TIER OF
COUNTIES THIS MORNING, WITH POTENTIAL FOR A STRONG TO MARGINALLY
SEVERE STORM OR TWO OVER THE EASTERN PLAINS LATER IN THE DAY.
OTHERWISE DRY FOR MOST OF THE AREA.
- EXPECT COOLER CONDITIONS THROUGH MONDAY, WITH MORE LIMITED
SHOWER AND THUNDERSTORM COVERAGE.
- GRADUAL WARMING RETURNS TUESDAY ONWARDS, WITH GENERALLY ISOLATED
PRECIPITATION CHANCES EACH DAY.
DISCUSSION /THROUGH SATURDAY/
ISSUED AT 1113 PM MDT SAT SEP 19 2026
SHOWERS CONTINUE TO TREK ACROSS THE MOUNTAINS AND NORTHERN TIER OF
OUR FORECAST AREA, ASSOCIATED WITH THE APPROACHING UPPER-LEVEL
TROUGH. AS ITS AXIS SHIFTS EAST, WE MAY SEE A FEW EMBEDDED
THUNDERSTORMS IN THE NORTH/NORTHEAST PLAINS AFTER SUNRISE. NOTABLY
COOLER TEMPERATURES CAN BE EXPECTED ACROSS THE LOWER ELEVATIONS,
WHERE HIGHS MAY STRUGGLE TO BREAK THE 70 DEGREE MARK IN THE COOLEST
AREAS (MAINLY THE PALMER DIVIDE AND FAR NE PLAINS). MOST AREAS WILL
SEE REDUCED CAPE RELATIVE TO PREVIOUS DAYS, LIMITING AFTERNOON
SHOWER/T-STORM COVERAGE CONSIDERABLY. HAVE FURTHER REDUCED POPS
ACROSS OUR MOUNTAINS AND URBAN CORRIDOR FOR THIS PERIOD, MAINTAINING
ONLY A VERY SLIGHT CHANCE (15-20%) OF PRECIPITATION. THE AXIS OF
BETTER INSTABILITY (AND SHEAR) WILL BE CONFINED TO OUR EASTERN
PLAINS, WHERE A FEW STRONGER TO MARGINALLY SEVERE STORMS MAY DEVELOP.
TRANSIENT RIDGING PUSHES IN FOR MONDAY INTO TUESDAY LEADING TO A
GRADUAL REBOUND IN TEMPERATURES AND COMPARATIVELY DRIER CONDITIONS.
AN ISOLATED SHOWER OR STORM COULD MAKE AN APPEARANCE MAINLY SOUTH OF
I-70 MONDAY, AND INCREASING SOUTHWEST FLOW AHEAD OF A DEVELOPING
CLOSED LOW OVER NEVADA ON TUESDAY SHOULD PROMOTE A FEW ISOLATED
AFTERNOON SHOWERS IN THE HIGH COUNTRY. THAT LOW IS THEN SLATED TO
LIFT NE, MERGING WITH THE BROADER FLOW PATTERN OVER THE NORTHERN
ROCKIES WEDNESDAY, PROMOTING A SLIGHT INCREASE IN SHOWERS AND
THUNDERSTORMS PREDOMINANTLY TO OUR MOUNTAINS, WITH MORE ISOLATED
COVERAGE ELSEWHERE.
BEHIND THIS, ENSEMBLE MEANS FAVOR STEADILY BUILDING HIGH PRESSURE
OVER COLORADO, SUPPORTING ADDITIONAL MODEST WARMING AND POTENTIAL
FOR TEMPERATURES TO RETURN TO THE 80'S FOR SOME OF THE LOWER
ELEVATIONS FOR THE SECOND HALF OF THE WEEK. PRECIPITATION CHANCES
WILL BE FAIRLY SLIM, BUT ENOUGH MOISTURE COULD REMAIN TRAPPED
BENEATH THE RIDGE TO ALLOW FOR ISOLATED AFTERNOON SHOWERS MOST
DAYS.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1108 AM MDT SUN SEP 20 2026
EXPECT VFR CONDITIONS THRU THE PERIOD. LIGHT AND VARIABLE WINDS
WILL GRADUALLY BECOME NE IN THE 19Z-20Z TIME PERIOD. BY 01Z WINDS
WILL BECOME MORE EASTERLY AND THEN TURN MORE SE BY 04Z. OVERNIGHT
WINDS WILL GO LIGHT AND VARIABLE BY 08Z. THERE IS A VERY LOW CHC
(5%) OF AN ISOLD SHOWER AT APA AND DIA BETWEEN 03Z AND 06Z.
BOU WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...BRQ
AVIATION...RPK
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