031
FXUS65 KBOU 291751
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1151 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
  southern 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 southern 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 /18Z TAFS through 18Z Thursday/...
Issued at 1139 AM MDT Wed Jul 29 2026

Scattered convection is likely to develop within the next couple
of hours, spreading east across the terminals between about 20-24z
this afternoon. Guidance is starting to back away from the
potential for TSRA at KBJC with slightly higher confidence at
DEN/APA. Could see impacts from both wind and brief visby
restrictions with any more organized storms. Some showers may
linger beyond 00z this evening though chances of impacts from that
will be lower.

Drainage winds should prevail this evening through most of the
overnight period, before becoming light and variable by Thursday
morning. There is a slight chance of additional showers/storms
near or after 18z Thursday, but coverage across the metro looks
far lower than today. Did introduce a PROB30 for -TSRA at DEN
tomorrow for now but may eventually remove that in future updates.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 9 PM MDT this evening for COZ041-046-047.

&&

$$

DISCUSSION...MAI
AVIATION...Hiris

NWS BOU Office Area Forecast Discussion