National Weather Service Forecast Discussion

Thornton Weather Forecast   
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203
FXUS65 KBOU 081830
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1230 PM MDT Wed Jul 8 2026

.KEY MESSAGES...

- Scattered to numerous thunderstorms, with a few strong to
  severe storms over the eastern plains.

- Another round of scattered to numerous thunderstorms Thursday,
  with the severe threat possibly expanding west to the Front
  Range.

- Prolonged period of hot temperatures arrive Saturday, lasting
  through at least Tuesday. Thunderstorm chances remain low during
  this period.

&&

.DISCUSSION /Through Wednesday/...
Issued at 1230 PM MDT Wed Jul 8 2026

Warm, dry, and gusty west winds prevail along and west of I-25.
Mid level moisture and a weak wavewill help produce
isolated/scattered high-based showers and thunderstorms this
afternoon with gusty outflow winds up to 60 mph possible with this
activity. Radar shows a boundary across Weld County where
west/northwest winds meet the northeast winds. East of this
boundary, the northeast winds are ushering in moisture with dew
points in the upper 50s to lower 60s. The main severe weather
threat today is east of the boundary. In addition to much better
moisture, ML CAPE reaches 500-1500J/kg. Main threat will be gusty
outflow winds up to 70 mph, but a few storms could produce severe
hail as well. Storms will progress eastward across the plains,
exiting the area this evening. A few overnight showers will also
be possibleover the mountains where a weak wave will track.

For Thursday, the pattern will generally be the same with a few
slight differences. We`ll see stronger westerly flow aloft
Thursday as a speed max passes over the area. Better moisture is
expected to push westward, but there is some uncertainty just how
far west it will be. Where better moisture resides, we`ll see
MLCAPE of 1000-2000J/kg and plenty of shear for severe
thunderstorms. The initial storms are expected to form over the
higher terrain. Storms should increase in strength and coverage as
they travel eastward, encountering better instability and
moisture. High-Res models favor a couple line segments. or
possibly one large line tracking across the eastern plains during
the afternoon and early evenings hours, favoring a strong wind
threat.

Upper level ridge off to the southwest begins to strengthen
Friday. Flow aloft weakens and turns to the northwest. Low level
flow will continue to be easterly, helping to hold onto better
moisture across the plains and possibly as far west as the urban
corridor. Expect another round of afternoon and early evening
thunderstorms to track across the urban corridor and eastern
plains.

For Saturday through Wednesday...the upper level high builds
northward and will be centered over the Central and Southern
Rockies Saturday. Temperatures will warm into the mid 90s across
northeast Colorado. Easterly low level winds may help hold some
moisture across eastern Colorado, however warm air aloft is
expected to cap the atmosphere, and prevent storms from forming.
The upper level high lifts northward and then remains semi-
stationary over the north central part of the country through the
middle of next week. Very warm temperatures are expected with
highs reaching the mid to upper 90s. Easterly low level flow will
prevail during this period and provide just enough cooling to
prevent widespread low 100 degree heat from occurring. These east
winds likelyhold in enough moisture to limit the fire weather
threat as well. Very warm air aloft continues to cap the
atmosphere. Can`t rule out a few thunderstorms over the higher
terrain early to mid next week. Steering winds will be from the
east, meaning storms will have a westerly component when they
develop. This will keep the urban corridor dry this weekend and
for most (perhaps all) of next week.

&&

.AVIATION /12Z TAFS through 12Z Thursday/...
Issued at 1230 PM MDT Wed Jul 8 2026

VFR conditions expected through the TAF period. North winds may
briefly be gusty this afternoon with gusts up to 20 knots possible
at DEN and APA and 30 knots at BJC. Scattered showers and storms
are expected to develop after 19Z with strong outflow winds that
could potentially reach 45 knots at DEN and APA. After these
storms move out of the area, southeast winds are expected to
develop late this afternoon and evening.

There will generally be light winds tonight with drainage flow
although a weak boundary may bring north winds at all terminals by
10-12Z.

Thursday looks similar to today with afternoon showers and storms
producing strong outflow winds up to 45 knots. The most likely
timing for storms is between 20-23Z.

&&

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

&&

$$

DISCUSSION...12
AVIATION...Danielson

NWS BOU Office Area Forecast Discussion