721
FXUS65 KBOU 261143
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
543 AM 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 on Sunday 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.

&&

.SHORT TERM /Through Saturday/...
Issued at 400 AM MDT Fri Jul 26 2024

Some similar and some different features are being observed this
AM compared to the last few days. Upper level RAP model analysis
shows the same ridge centered around the Baja Peninsula, extending
NE`ward through CO. One notable difference, seen on mid-level
water vapor satellite imagery, is an elongated plume of moisture
spanned across western/central CO. Ensemble guidance shows that
this plume of above normal moisture will gradually shift eastward
over the mountains/foothills and into the I-25 corridor this
afternoon. In terms of how above normal, it is around 110-140% of
normal. Precipitable water values range from 0.6-0.8" for the
higher terrain and 0.8-1.2" across the I-25 corridor. This will
support increased chances for precipitation this afternoon.

Upper level support is fairly limited today. A weak 500mb trough
moves through the flow by tonight providing weak synoptic ascent.
Instability will be marginal with MLCAPE values < 800 j/kg. These
ingredients will still be sufficient to support scattered showers
and thunderstorms this afternoon/early evening. Some storms may
contain small hail, gusty winds, and localized heavy rainfall for
the higher elevations. With localized heavy rainfall comes the
potential threat to the burn areas. That is discussed further in
the hydro discussion below. Showers/storms develop in the
mountains/foothills by early afternoon, extending eastward onto
the adjacent plains. Model soundings exhibit a sufficient amount
of dry air remaining at the surface at the lower elevations
reducing the heavy rain potential and increase the threat for
gusty outflow winds. DCAPE values 1000-1600 j/kg paired with
inverted v sounding profiles reflect this potential quite well.
This could mean some storms or dissipating ones may be capable of
gusts up to 50 mph. Showers/storms move out and/or dissipate early
this evening. For temperatures, highs will be slightly cooler
with cooler 700mb temperatures and increased cloud cover. Most of
the urban corridor will see low 90s and low to mid 90s for the
east plains.

&&

.LONG TERM /Saturday night through Thursday/...
Issued at 400 AM MDT Fri Jul 26 2024

Flow of subtropical moisture will continue on Sat in WSW flow aloft.
Precipitable water values will be in the 0.80" to 1.00" range with
sfc based cape in the 500-1000 j/kg range. Showers and storms
will increase over the higher terrain by midday with activity
spreading eastward across the plains during the aftn. DCAPE over
the plains will be up to 1500 j/kg so expect gusty outflow winds
from some of the storms. Storms will be moving but can`t rule out
some locally heavy rainfall in some areas due to favorable
precipitable water values. Highs on Sat will remain above normal
with readings in the 90`s across the plains.

By Sun, drier air in westerly flow aloft will move into the area.
Thus shower and tstm activity will be more widely sct and confined
mainly to the higher terrain.  Highs over the plains will range from
95 to 100 degrees.

For Mon thru Wed, dry westerly flow aloft will be over the area.
This will lead to mainly dry and hot weather with highs in the upper
90`s to lower 100`s across the plains.  Thus may see a few records
tied or bkn during this period.

&&

.AVIATION /12Z TAFS through 12Z Saturday/...
Issued at 543 AM MDT Fri Jul 26 2024

VFR conditions expected through the TAF period. Winds gradually
decrease early this morning becoming SW/WSW. Light winds
transition "around the horn" from WSW around to NE by the
afternoon. Scattered showers and thunderstorms return to the
forecast with chances this afternoon, mainly between 21-03Z. Winds
will generally keep a westerly component with storms coming off
the higher terrain to the west. Storms may contain variable gusty
winds for periods which has been reflected as a TEMPO within the
storm timeframe. Lacking moisture at the lower elevations and
scattered coverage have kept -TSRA out of the TEMPO for now. Gusts
mainly up to 35 kts, but can`t rule out a stronger storm with
localized gusts up to 45 kts. Winds return to drainage flow
overnight at APA/DEN and WSW at BJC. Light and variable winds
Saturday morning.

&&

.FIRE WEATHER...
Issued at 400 AM 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 400 AM MDT Fri Jul 26 2024

ABove normal moisture shifts into the region today, around
110-140% of normal with precipitable water values 0.6-0.8" for the
high country and 0.8-1.2" for the I-25 corridor. Localized heavy
rainfall in the higher elevations will be the main concern due to
the burn areas. With weaker winds aloft, storm motions will lean
on the slower side thus resulting in a limited threat for flash
flooding over the burn areas today.

Enough moisture will remain across the region on Saturday for
another round of showers and thunderstorms. There will be a limited
threat for flash flooding in the burn scars. Beyond Saturday, the
pattern dries out and warms up through the middle part of next
week.

&&

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

&&

$$

SHORT TERM...Mensch
LONG TERM...RPK
AVIATION...Mensch
FIRE WEATHER...RPK
HYDROLOGY...Mensch/RPK