394
FXUS65 KBOU 250544
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1144 PM MDT Mon Jun 24 2024

.KEY MESSAGES...

- Continued Hot Tuesday with Heat Advisory for the Denver Metro.

- High based showers and thunderstorms this afternoon into the
  early evening with gusty winds.

- Slight cool down and increased chances for thunderstorms
  Wednesday and Thursday.

- Some storms on Wednesday could be strong with heavy rain and
  severe weather, especially across the plains east of Denver.

&&

.UPDATE...
Issued at 851 PM MDT Mon Jun 24 2024

Although low temperatures will hover near the mid to upper 60s
tonight for Boulder, Jefferson, and Broomfield counties, the Heat
Advisory was allowed to expire. An additional Heat Advisory
continues for Denver until 9 PM MDT Tuesday. Outflows from
decaying showers should end within the next hour or two.
Adjustments to wind direction and slightly higher speeds were
include in this update until midnight.

&&

.SHORT TERM /Through Tuesday/...
Issued at 125 PM MDT Mon Jun 24 2024

Mid level moisture in weak westerly flow aloft is moving across the
area this aftn.  MLCAPE is around 500 j/kg which is allowing for sct
showers/storms over the higher terrain with activity over the plains
more widely sct.  DCAPE values are around 1500 j/kg so a few of the
storms may still produce wind gusts to 50-55 mph.  This activity
will linger into the early evening hours before ending around 03Z or
so.

On Tue, it appears there will be a decrease in overall moisture
along with not as much instability.  Thus expect any high based
shower/tstm activity will be more isold and confined to mainly
the higher terrain. Highs will remain well above normal with
readings in the 95 to 100 degree range across much of the plains.
Will keep the heat advisory in place for the Denver metro on Tue
as well.

&&

.LONG TERM /Tuesday night through Monday/...
Issued at 125 PM MDT Mon Jun 24 2024

Upper level high pressure will remain centered over the Central and
Southern Rockies Tuesday night and Wednesday with above normal
temperatures continuing. Models are showing a weak cool front moving
across Northeastern Colorado Tuesday evening with increased low
level moisture behind it. There should also be an increase in
subtropical moisture moving into Colorado from the Desert Southwest.
As a result, slightly cooler temperatures are expected across the
forecast area along with a better chance for precipitation region
wide. With PW`s on the plains ranging from 1.00" to over 1.50" there
is the potential for heavy rain, especially east of the Front Range
Urban Corridor. In addition, some of the models are suggesting the
potential for a few strong to severe storms mainly east and
northeast of Denver during the afternoon and evening hours due to
quite a bit of instability and plenty of shear. With the additional
cloudiness and precipitation around, temperatures should be somewhat
lower than previous days, but still hot with highs in the upper 80s
to mid 90s on the plains.

On Thursday, the upper ridge flattens in response to an upper level
shortwave moving across the Northern Rockies. Moisture levels and
shear should be somewhat less. Consequently, there may be a lower
threat for severe storms and heavy rain than on Wednesday. One thing
to note is that the GFS deterministic and ensemble runs as well as
the GEM solution is showing quite a bit of precipitation across
portions of the high country Thursday evening. Nothing really stands
out when looking at the models other than a southwest to northeast
50kt upper jet moving over Western and Central Colorado which could
be the reason for the enhanced precipitation. Due to the model
differences, there is quite a bit of uncertainty if the heavier
precipitation will occur.

Friday looks to be somewhat drier and cooler across the CWA as we
see some cool air advection at mid levels and downsloping flow east
of the mountains. Saturday looks to be the coolest day of the week
as another cold front moves across the region. Max temperatures on
the plains are only expected to climb into the upper 70s and lower
80s. Precipitation chances may be limited across far Northeastern
Colorado due to the presence of a cap with better chances across the
high country, adjacent plains and Palmer Divide. There should still
be enough available moisture and instability to produce a few
stronger storms with brief heavy rain and small hail, mainly over
the higher terrain.

On Sunday, the models show the upper high centered over Arkansas
with an upper trough over the western U.S. This is more of a classic
monsoon setup and if it verifies, we could see more numerous showers
and storms across the forecast area with the potential for heavy
rain in some areas. There is also the potential for some severe
weather across the plains as surface winds turn southeasterly and
richer low level moisture advects into the area.

By Monday, precipitation chances may decrease as the monsoonal plume
of moisture gets shunted south and eastward in response to the upper
trough pushing into Colorado from the west.

&&

.AVIATION /06Z TAFS through 06Z Wednesday/...
Issued at 1144 PM MDT Mon Jun 24 2024

Southerly drainage winds to prevail at DEN and APA through early
to mid morning (14-16Z). Winds then transition to a northerly
direction for Tuesday afternoon. High based gusty showers develop
after 20Z Tuesday, with a wind shift or two possible. Chances for
a weak thunderstorm are low, about 10 percent. Threat for showers
and wind shifts end 03-06Z with southerly drainage winds kicking
in.

&&

.HYDROLOGY...
Issued at 125 PM MDT Mon Jun 24 2024

Increased moisture will lead to a potential for moderate to heavy
rain across the forecast area Wednesday and Thursday. The plains
east of the Front Range Urban Corridor will see the greatest
threat late Wednesday afternoon and evening. We may see another
threat for heavy rain across portions of the forecast area on
Sunday as monsoonal moisture moves over the area.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM MDT Tuesday for COZ040.

&&

$$

UPDATE...AD
SHORT TERM...RPK
LONG TERM...JK
AVIATION...Meier
HYDROLOGY...JK