547
FXUS65 KBOU 262050
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
250 PM MDT Fri Jul 26 2024

.KEY MESSAGES...

- Numerous showers and thunderstorms for the mountains today and
  Saturday, with scattered storms on the plains.

- Elevated fire weather conditions are expected over the
  higher terrain and South Park on Sunday and Monday due to hot,
  dry, and windy conditions.

- Trend towards hot and dry continues late weekend into next week.

- A few daily records tied or broken is very feasible with the upcoming
  heat as we broach the triple digits again, Monday - Wednesday.
  &&

.SHORT TERM /Through Saturday/...
Issued at 219 PM MDT Fri Jul 26 2024

While smoky skies have lingered into the afternoon along the Front
Range, associated air quality has improved over the past few days.
With the shifting wind patterns aloft transitioning to a more
westerly pattern later today, continued improvements are expected.
The only caveat is whether the W/WSW flow starts to bring in smoke
from the wildfires currently burning in California. The latest run
of the HRRR Vertically Integrated Smoke shows a hefty plume of
high concentrations expected to enter western WY and southwestern
Utah in the next day. This will continue to be monitored in the
coming days. The shifting pattern will also be responsible for
increased moisture across the forecast area today and tomorrow.
Current satellite imagery shows a plume of mid- and low- level
moisture extending from the Baja region into central and eastern
Canada and passing directly through Colorado. Slow moving storms
have already developed over the mountains early this afternoon.
SPC mesoanalysis currently shows PWAT values between .7" to .8"
across the forecast area. These storms are expected to be
scattered in nature and the HREF indicates a 40% chance that some
of the stronger storms may contain pockets of .25"/hr
accumulations. The HREF LPMM accumulated precipitation portrays
our areas of greatest concern for heaviest rainfall to be in
portions of central Larimer County, and southern Clear
Creek/northern Park Counties between the 2-5 PM time frame. The
storms in Larimer County may develop or pass over some of our burn
scars and will be monitored for flash flooding concerns. With
forecast soundings showing DCAPE values surpassing 1000 J/kg,
gusty outflows are expected with these storms as they move east
off the higher terrain and begin to dissipate over the lower and
less favorable environment across the plains. Gusts are expected
to be in the 30-35 mph range with a chance of a few gusts
surpassing that with the stronger storms. Overnight temperatures
are forecast to be in the 60s across the plains and 40s for the
higher elevations.


Tomorrow will bring another round of scattered to numerous storms
and showers. With more instability expected, there is a better
chance of these storms making their way onto the plains than
today`s. With the increased instability and some better shear,
these storms have a better chance of becoming slightly more
organized which could bring increased chances for producing some
hail, mainly for the northeastern portion of the forecast area.
High temperatures are expected to surpass the 90s once again
across the plains and high 70s/low 80s for the mountains. Expected
cloud coverage should help take the edge of the heat in the
afternoon.


&&

.LONG TERM /Saturday night through Friday/...
Issued at 219 PM MDT Fri Jul 26 2024

At this point in time with the upcoming heat we`re trying to define
if it`ll be 98 degrees, not the band, or 100 degrees across the
urban corridor and 100 to 105 degrees over the plains from Monday
through Wednesday of next week. Ensemble probabilities have been
showing the signal for 100F for several days now with probabilities
inching higher as of today. Tuesday and Wednesday look to be the
hottest days with the coarser ensemble data showing a 60-70% chance
of reaching 100F from the Denver Metro to the north and east across
the plains. That is not to say that the other days during the long
term period aren`t hot, they are just not as hot.

Though not a definite correlation, the last time across the metro
area and plains to make a run at three consecutive days of 100F,
just two weeks ago, 500mb heights were 594dm. At this time we`re
seeing a 90+% chance of having heights exceed that level on numerous
pieces of ensemble guidance. Some moisture does try to increase
later in the period, even with these deeper heights, but cloudiness
could keep us a degree or two cooler by Thursday and Friday of next
week. Any shower or storm activity looks to be confined to the
higher terrain as well, again late period.

&&

.AVIATION /18Z TAFS through 18Z Saturday/...
Issued at 1141 AM MDT Fri Jul 26 2024

Storms have developed over Jefferson County and are slowly moving
east towards BJC. These storms may be associated with gusty winds
reaching 35 kts at times. Some stronger storms may even contain
localized gusts up to 45 kts through the afternoon and early
evening. These storms are expected to continue eastward and bring
gusty winds to DEN and APA in the coming hours. Tomorrow will see
a similar pattern as today with afternoon thunderstorms and gusty
outflow winds expected at all TAF sites. Guidance indicates
tomorrow`s wind gusts may be slightly higher than today`s.

&&

.FIRE WEATHER...
Issued at 219 PM MDT Fri Jul 26 2024

Elevated to critical fire conditions will be in place over the
higher terrain both Sunday and Monday due to gusty winds, low
humidity and above normal temperatures. Across the plains winds
will be lighter, however, hot and dry conditions will lead to
elevated fire conditions.

&&

.HYDROLOGY...
Issued at 219 PM MDT Fri Jul 26 2024

Slow moving storms this afternoon and evening are expected over
the high country, with a chance of some making their way to
adjacent lower elevations. With increased moisture across the low
to mid- levels, some localized heavy rainfall is possible. The
main concern is the limited threat of flash flooding over the
burn scars, mainly for those residing in Larimer County.

Enough moisture will remain across the region on Saturday for
another round of showers and thunderstorms. There will again, be a
limited threat for flash flooding in the burn scars. Hot and dry
conditions are the main concerns Sunday through the end of the new
work week.

&&

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

&&

$$

SHORT TERM...Bonner
LONG TERM...Heavener
AVIATION...Bonner
FIRE WEATHER...Bonner/Heavener
HYDROLOGY...Bonner/Heavener