FXUS65 KBOU 211121

AFDBOU



Area Forecast Discussion

National Weather Service Denver/Boulder CO

521 AM MDT Sun Jun 21 2026



.KEY MESSAGES... 



- Strong to severe storms possible across the far eastern plains

  today. Otherwise, temperatures holding steady with elevated fire

  weather conditions in the high country and some patchy smoke

  aloft from wildfires in Utah.



- Increasing coverage of afternoon thunderstorms early to mid

  week, with continued potential for severe thunderstorms,

  especially in the plains.

 

- Slightly moderated temperatures midweek, with drier and warmer

  weather returning for the weekend.



- Elevated to at times locally critical fire weather conditions

  will persist much of the week in the high country.



&&



.DISCUSSION /Through Saturday/...

Issued at 105 AM MDT Sun Jun 21 2026



Stratus has become relatively widespread across the lower 

elevations in the wake of yesterday's front, though should largely

remain elevated enough to keep any dense fog patchy in nature, 

more prevalent over the higher elevations of the Pawnee 

Grasslands. Cross-sections point to a fairly early mixing of

westerly and southwesterly flow this morning which should help

dissipate lingering stratus shortly after sunrise. Mostly elevated

smoke will also be present at times today, stemming from ongoing

wildfire activity in western Utah.



Today's convective forecast remains on track, with a modest

dryline progged to settle in our eastern plains and allow for an

axis of greater instability this afternoon/evening across our

easternmost tier of counties. Shear doesn't appear to be overly

impressive, but a few pockets up to around 40 kts look to be

present in the plains. Wind and hail will be the primary severe

weather threats in the plains today. Farther west, drier air will

be in place through ~500mb under weakly subsident flow, hindering

instability and precipitation chances. Some virga and isolated

showers will be more likely for the urban corridor, along with a

few gusty outflows. Temperatures look to hold steady under the

subsident pattern. In the mountains, lingering breezy and dry

conditions will sustain elevated to near-critical fire weather

conditions.



Another weak shortwave arrives Monday, with the dryline

experiencing a westward nudge and PW values climbing to between

0.80-1.00" for most of the plains. Despite a slight cooldown,

elevated dewpoints will promote increased instability and thus

greater thunderstorm coverage for the lower elevations, including

the I-25 corridor. Still, the higher potential for severe

convection will remain over the rural plains. In the high country,

gusty west winds resulting from strengthening zonal flow will lead

to near-critical and potentially critical fire weather conditions

for some locations.



Moist easterly flow will remain anchored in place Tuesday into

Wednesday, maintaining at least scattered afternoon showers and

thunderstorms for most of the area as well as cooler temperatures

despite some height rises aloft. Precipitation chances for the

urban corridor look to be the highest during this period, and may

extend into Thursday depending on how quickly the pattern evolves.



A warming and drying trend is favored as we head towards the

weekend, with ensemble means indicating healthy potential for

temperatures climbing into the mid/upper 90's for the lower

elevations by Saturday. 



&&



.AVIATION /12Z TAFS through 12Z Monday/...

Issued at 512 AM MDT Sun Jun 21 2026



Low stratus has retreated east of the I-25 corridor including

KDEN, with only localized patchy stratus lingering in a few

locations. Given current wind directions, see little reason for

stratus to rebound west with any significance, so have proceeded

with maintaining all terminals under VFR conditions for the

remainder of the TAF period. Of note however, light to moderate

concentrations of wildfire smoke from Utah do look to persist

particularly through the morning hours, most likely between the

050-080 levels, which may impact slantwise visibility at times.



Winds are expected to turn NW/N with daytime mixing, although have

pushed the breezier conditions back by 1-2 hrs considering typical

overmixing biases in model guidance. Winds will continue turning

clockwise through the afternoon and eventually return to drainage

this evening.



Convection is anticipated to remain east of all Denver area

terminals today given minimal instability over the urban corridor

and dry low-levels, although isolated virga and outflows cannot 

be ruled out for any of the terminals.



&&



.BOU WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



DISCUSSION...BRQ

AVIATION...BRQ