National Weather Service Forecast Discussion

Thornton Weather Forecast   
Today's Forecast Story   
012
FXUS65 KBOU 071201
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
601 AM MDT Tue Jul 7 2026

.KEY MESSAGES...

- Increased moisture expected to bring an uptick in shower and
  storm coverage this afternoon and evening, with an isolated
  severe threat along the Cheyenne Ridge.

- Higher probabilities of thunderstorms with a few strong to
  severe storms possible from the Front Range eastward on Wednesday
  and Thursday.

- Isolated dry thunderstorms in mountains could spark new
  wildfires.

- Heat wave arrives this weekend, with minimal chance of any
  thunderstorms for heat relief.

&&

.DISCUSSION /Through Monday/...
Issued at 219 AM MDT Tue Jul 7 2026

Water vapor imagery shows moisture wrapping around an upper-level
ridge centered near the Four Corners early this morning. While
the better moisture will pass to our north, some mid-level and
upper-level moisture will make it into Colorado by this
afternoon, where high-based storms and showers are expected to
develop and move from west to east across the forecast area.
Isolated dry lightning will be possible across the higher
elevations through the afternoon. Gusty outflows will be the main
hazard for today`s convection, with forecast soundings showing
around 1500-1700 J/kg of DCAPE, and CAMs showing storms becoming
linear as they propagate eastward across the plains. The SPC has
highlighted areas along the Cheyenne Ridge with a Marginal Risk
for today (1/5 risk level) for an isolated severe wind gust and hail
threat, though the hail threat is expected to be minimal. Shear will
be a limiting factor for more organized storms today, with 0 to 6km
bulk shear ranging between 20-25kts, but the aforementioned DCAPE
values would support potential for severe winds between 60-70mph.
Temperatures will be a few degrees cooler than Monday, but remain
in the mid to upper 90s across the plains. Patchy smoke will
persist along and east of the Front Range.

Storm coverage and strength will increase on Wednesday and
Thursday with higher instability and shear allowing for more
organized storm potential. CAMs show between 700-1400 J/kg of
MLCAPE across the plains on Wednesday, with the NAMNEST pulling
the higher instability all the way west to the urban corridor
(dewpoints in the 60s) where the HRRR keeps it primarily in the
far northeast corner (dewpoints in the 50s). The RAP seems to
split the difference, which would be aligned with the latest SPC
assessment where they have issued a Slight Risk for areas along
the Cheyenne Ridge to the NE/KS border for wind and hail, which
seems reasonable at this time since 0-6km bulk shear is also
expected to increase to 30-40kts in this same area. A slight
uptick in shear (30-45kts) is expected on Thursday that will bring
another day of a few strong to severe storms across the plains,
though the greater moisture is expected east of the urban
corridor, where the SPC has outlined a Marginal Risk for their Day
Three Outlook. Temperatures will gradually cool down each day,
with Thursday likely seeing afternoon highs sub 90F across the
plains.

Precipitation chances will begin to diminish on Friday as the
highly advertised upper-level ridge begins to build over the
Rockies. There will likely still be enough residual moisture in
place for some afternoon convection, but subsidence and lacking
shear will likely limit any real organization. Temperatures will
begin to increase, but a more noticeable warming is expected on
Saturday and into early next as temperatures reach for the
triple-digits. Precipitation chances will be limited under strong
subsidence.

&&

.AVIATION /12Z TAFS through 12Z Wednesday/...
Issued at 543 AM MDT Tue Jul 7 2026

South to southwest winds are in place at KDEN/KAPA with light and
variable winds at KBJC this morning. Smoke is prevalent on webcams
once again that is expected to reduce slant-range VIS and bring
IMC conditions through at least the morning. Shower and storm
coverage is expected to increase today, moving within the
vicinity of the TAF sites by 19Z-21Z, impacting KBJC/KAPA
followed by KDEN. These should be fairly high-based showers again,
with CIG expected to remain at or above 10,000` AGL and DCAPE
expected to be around 1500 J/kg across the area. Expect gusty
outflows between 35-45kts possible with passing showers/storms. A
few showers may persist in the vicinity of the TAF sites through
around 5Z that may delay winds from settling into drainage. Low
confidence in wind direction between the exit of storms and the
development of drainage winds (expected by 6-7Z), but with storms
expected to exit to the east, there is higher confidence in a more
easterly component from outflows.

Latest guidance suggests some slight improvements to smoke
concentrations for tomorrow morning that increased confidence
high enough to keep FU out of the TAF for the morning Wednesday.
This could easily change depending on today`s fire behavior
though, so will continue to be assessed through upcoming TAF
packages.



&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...9
AVIATION...9

NWS BOU Office Area Forecast Discussion