329
FXUS65 KBOU 111147
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
547 AM MDT Wed Jun 11 2025

.KEY MESSAGES...

- Gusty winds up to 50 mph from high based-showers and
  thunderstorms late this afternoon and evening.

- Warming trend with above normal temperatures through Friday.
  Even warmer weather possible this weekend.

- Chance of afternoon showers and thunderstorms mainly over the
  higher terrain most days. Best chance of rain comes Wednesday
  and Thursday.

&&

.DISCUSSION /Through Tuesday/...
Issued at 216 PM MDT Tue Jun 10 2025

A warm dry airmass is in place across the area. Noon temperatures
were already well into the 80s with dew points in the 30s. The
latest hi-res models seem to agree we will see some high-based
convection later today, mainly in the form of showers, though a
few thunderstorms will be possible over the mountains. Any
rainfall, is expected light, but gusty outflow winds will be
likely due to the large temperature/dew point spreads. This
activity quickly dissipates this evening as the air stabilizes.

For Wednesday and Thursday, the upper level pattern is messy with
a trough over the Southern Plains and a second one passing north
of Colorado. Shortwave riding forms over Colorado in response to
the deepening trough to our southeast. Moisture does increase a
little for Wednesday and Thursday. This is expected to lead to an
increase in showers and thunderstorms. Limited moisture,
instability, and weak shear is expected to keep storms sub-severe.
The far eastern plains could see a couple severe storms if the
better instability and shear shifts westward a little. As far as
temperatures go, they are expected to stay above normal with highs
in the mid 80s to lower 90s across northeast Colorado.

On Friday, the shortwave ridging slides off to the east and flow
aloft increases. Large scale ridging begins, but is more
pronounced this weekend. Surface high pressure over the Northern
Plains will lead to east to southeast winds across the eastern
Colorado plains, increasing the moisture and shear. A dry line
sets up where the southeast winds intersect the drier west winds.
If we are to see severe thunderstorms this upcoming week, Friday
looks like the day as instability will be enough for strong/severe
storms. The storms could still run into issues forming, such as
too warm air aloft from the developing ridge and also we may not
see as much moisture return to the area as the models show.

Upper level ridge will be centered over the Central and Southern
Rockies this weekend. Not surprising, this will lead to warmer
temperatures with highs reaching the upper 80s to mid 90s across
northeast Colorado. Sunday is looking like the slightly warmer and
drier day. The 12Z GFS shows a decent batch of late afternoon and
evening showers/storms, but nearly all (more than 90%) of the
ensemble members of the GFS and ECMWF indicate dry conditions.
Given the ridging overhead along with the limited moisture and
instability, dry conditions would be expected.

For early next week (Monday and Tuesday), the ridging over the
region eventually is flattened or pushed off to the east by an
upper level trough moving in from the Pacific. Models still
greatly vary when and how this will happen. Will keep the cool
down gradual for Monday and Tuesday and PoPs generally on the low
side (20-30%) during the afternoon and evening hours.

&&

.AVIATION /12Z TAFS through 12Z Thursday/...
Issued at 521 AM MDT Wed Jun 11 2025

The main concern today will be afternoon thunderstorms. Model
guidance has come into better agreement that a wave of storms will
likely move over or near all terminals between 20-00Z this
afternoon. The primary threat will be wind gusts that could reach
40 knots. In addition, ceilings in the 5,000-7,000 range are
possible. There was enough of an increase in confidence that
storms will impact the terminals to put a TEMPO in the TAFs
instead of a PROB30. Otherwise, winds will be light during the day
today and will shift to a light drainage tonight.

&&

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

&&

$$

DISCUSSION...Meier
AVIATION...Danielson