848
FXUS65 KPUB 152338
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
538 PM MDT Mon Jul 15 2024

.KEY MESSAGES...

- Showers and thunderstorms are expected to last through this
  evening, with strong outflow winds.

- Slight Risk for severe weather Tuesday evening. Main risks
  will be strong winds of 40 to 60 mph over the adjacent plains
  and 1.5"+ hail, 60 to 70 mph wind gusts, and an isolated
  tornado close to the Kansas border.

- Flash flood risk for the mountains and the I-25 corridor Wednesday
afternoon and evening.

- Monsoonal thunderstorms will continue throughout the forecast
  period.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 230 PM MDT Mon Jul 15 2024

Currently...

Isolated thunderstorms have already popped up across the higher
terrain and parts of our northern I-25 corridor. SPC Mesoanalysis
page is showing around 1500 J/kg of DCAPE depending on where you
look across the plains and I-25 corridor, and observations are
showing some pretty large dewpoint depressions. As such, gusty
outflow winds continue to be our main concern this afternoon.


Rest of Today and Tonight...

Shower and thunderstorm coverage will continue to increase this
afternoon and evening, with northwest steering flow aloft pushing
activity off of the mountains and onto the adjacent plains within
the next few hours. While scattered convection will be possible this
evening for the entire eastern plains, the best chance for any
stronger storms will be along and north of Highway 50 where
effective bulk shear is maximized closer to 30-35 knots. While some
storms may be capable of producing moderate to briefly heavy
rainfall, given the dewpoint depressions and sounding profiles, our
biggest convective impact risk for today will be strong outflow
winds. As we move into the overnight hours, showers and storms will
dissipate, mostly leaving the area by around 10pm.


Tuesday...

The upper-level ridge will break down on Tuesday as a cold front is
pushed south across the eastern plains, hinting at the end of this
stretch of excessive heat. High temperatures will be in the high-80s
to mid-90s across the eastern plains, and mainly spread across the
80s for the mountain valleys.

Looking at precipitation chances, the extent of showers and
thunderstorms tomorrow afternoon will likely depend on a few key
factors. First, the timing of the cold front will play a key role in
localized lift and an influx of better moisture. Additionally, winds
behind the front will quickly turn more northeasterly, allowing for
some moist upslope into our higher terrain. Next, looking aloft, a
perturbation to the mid and upper-level flow will be passing over
tomorrow afternoon, coinciding with some lee troughing near the
surface. Between that and the front, there will be plenty of lift
across the area to help initiate storms. Meanwhile, high-res models
are plotting varying amounts of CAPE, depending on which model you
look at, with most in support of a decent amount of convective
activity. Even some of the less enthusiastic models, such as the
GFS, are showing between about 600-1200 J/kg, while more aggressive
models bring in a larger wedge of unstable air behind the front,
getting closer to 2000 J/kg by early afternoon. Then, given the
easterly post-frontal winds at the surface along with breezy
northwest winds aloft, bulk shear should be 30-35 knots or more. So
overall, Tuesday is shaping up to be an active convective day, with
thunderstorms forming over and near the mountains during early to
mid-afternoon before moving off to the east-southeast. Storms will
intensify as they approach the Kansas border, where instability will
be at its highest. Convection is not expected to be very isolated in
nature, with wider overall coverage on account of the easterly
upslope. However, a few discrete cells cannot be ruled out. In
general, main concerns for tomorrow will be strong outflow winds,
large hail, and heavy rainfall with the possibility of flash
flooding in vulnerable areas. Most of the stronger to severe storms
will be over the eastern plains, but the mountains could still see
some heavy rainfall and gusty winds as well.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 230 PM MDT Mon Jul 15 2024

Tuesday Evening:

There is a slight risk for severe weather outlooked over our far
eastern plains on Tuesday afternoon. The short term forecast has the
hazards over the I-25 corridor, but the far eastern plains is
expected to have between 1000-2000 J/kg of MUCAPE, around 30 kts of
0-6km Bulk Shear, and a straight line hodograph in place. All of
this leads to all hazard risks as splitting supercells are expected
with this type of set-up. 1.5"+ hail, 60 to 70 mph wind gusts, and
an isolated tornado are all possible with the risk increasing near
the Kansas border.

Wednesday:

The post frontal airmass creating east-southeasterly winds all along
the plains towards our mountains. There is around 1500 J/kg of
MUCAPE all along the eastern mountains and the plains. In
Wednesday`s case, the further east you travel, the stronger the CIN
and the closer to the mountains the less CIN there is. This really
confines the flash flooding and severe risk to over the adjacent
plains and the eastern mountains. The CAPE profile over those
regions has long and skinny CAPE, which is a very good sounding for
very heavy rains. I am not issuing it right now, but a Flash Flood
Watch may be needed over the eastern mountains and I-25 corridor on
Wednesday afternoon and evening. We`ll need to pay close attention
to the population areas, especially in low lying areas, and our
active burn scars, the Spring Creek and Decker burn scars.

Thursday through Sunday:

Like mentioned before, the high pressure will remain over the desert
southwest, wobbling slowly further to the west by the end of the
forecast period. This results in daily chances for thunderstorms
over the mountains that spread over the eastern plains. There always
seems to be this looming moisture boundary near the Kansas border
that has around 1500 J/kg of MUCAPE and 30-40 kts of 0-6km Bulk
Shear, but by time the thunderstorms reach that area, the night time
inversion stabilizes the atmosphere. So main risks are going to be
heavy rains over the mountains. The severe thunderstorm risk over
this area is pretty limited due to the lack of shear.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 531 PM MDT Mon Jul 15 2024

VFR at all taf sites overnight and through the first half of
the day on Tue, then potential for some brief MVFR/IFR at all
terminals after 20z Tue due to tsra activity. For this
evening, main outflow boundary is through both KCOS and KPUB,
and expect any convection here to be isolated and brief. Still
some gusty storms across the San Luis Valley, so will maintain
an vcts through 02z-03z, before activity diminishes. On
Tue, cold front will switch winds to the e-ne at KPUB/KCOS
18z-20z, with vcts then expected after 20z as storms develop
along/behind the front. At KALS, afternoon storms again likely
after 20z over the San Luis Valley, with gusty/erratic outflow
winds into the evening.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 6 PM MDT this evening for COZ083>086-093-
097-098.

&&

$$

SHORT TERM...GARBEROGLIO
LONG TERM...SKELLY
AVIATION...PETERSEN