658
FXUS65 KPUB 241118
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
518 AM MDT Mon Jun 24 2024

.KEY MESSAGES...

- Dangerously hot temperatures are expected today and Tuesday,
  especially for El Paso, Pueblo, and eastern Fremont counties.

- Isolated to widely scattered showers and thunderstorms are
  expected today, mainly along and near the higher terrain and
  our far southeastern plains.

- Influx in moisture late week will bring an uptick in
  thunderstorm chances with stronger storm strengths and heavy
  rainfall possible Wed-Fri.

- Cold front will bring an end to the 100 degree readings and a
  much needed cool down across the plains this weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 342 AM MDT Mon Jun 24 2024

|Currently..

Satellite imagery reveals that we are along the northern periphery
of the subtropical high this morning, with mostly clear skies and
above normal temperatures across the area. Most of our plains are
still in the upper 60s and low 70s as of 2am, with dewpoints in the
30s and 40s. Winds are light and following normal drainage patterns
in most mountain and mountain adjacent locations.

Today and Tonight..

Models strengthen the upper-level ridge and drag it more overhead
throughout the day today, which will make for very hot temperatures
across the forecast area. Many locations will see daytime highs well
into the triple digits, and most areas will be around 12 to 16
degrees above normal for this time of year. The Lower Arkansas River
Valley will see highs in the 102 to 104 range. Elsewhere on the
plains, expect highs in the upper 90s to low 100s, with our mountain
valleys topping out in the mid 80s to low 90s. A Heat Advisory
remains in effect for El Paso, Pueblo, and eastern Fremont counties,
where Category 3 heat indices are expected this afternoon.
Vulnerable populations should take extra precautions today, along
with anyone who has to spend extra time outdoors. Try to limit time
in the sun and remain hydrated! Another influx of subtropical
moisture looks to arrive this afternoon as well, which should allow
for another round of isolated to widely scattered showers and
thunderstorms over and near the higher terrain, along with our far
southeastern plains. For storms over the mountains, gusty outflow
winds and lightning will be our main concerns. For our far southern
plains, a few stronger storms may be possible later this afternoon
and into this evening. Models indicate that this area could see
around 40kt of deep layer sheer, along with around 1400 J/Kg of
SBCAPE and 1800 J/Kg of DCAPE later on today. With any storms that
manage to get going over our southeastern plains, small hail and
wind gusts up to 55 mph will be possible today. High res model
guidance suggests that convection should die off fairly quickly
after sunset, though outflow interaction from any lingering storms
could keep things going in some areas. The general consensus seems
to end precip chances by around 10pm at the latest. With clear skies
and dry conditions overnight, we should cool efficiently, with
overnight lows falling well into the 60s across our plains by
Tuesday morning. It is probably worth noting though that any
overperforming showers, cloud cover or even just lingering moisture
in general tonight will lead to warmer overnight temperatures, and
an even warmer start to an already scorcher of a forecast for our
Tuesday.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 342 AM MDT Mon Jun 24 2024

Upper ridge builds northward, with Tuesday looking like the hottest
day of the week across southern CO.  We could get close to record
highs which are 93 in ALS, 98 in COS and 105 in PUB all set in 2012.
For now forecast high temperatures are 2-5 degrees below records
with PUB standing the best chance of seeing a tie.  With the very
hot temperatures another round of Heat Advisories have been
issued for El Paso, Pueblo and eastern Fremont counties which
will run from 11 AM to 7 PM Tuesday. Otherwise, mountains and
valleys will be very warm as well. Residual mid and high based
moisture will be sufficient for isolated high based
thunderstorms over the mountains and possibly along a surface
trough axis across the eastern plains. Gusty winds and lightning
will be the primary risks. Thunderstorms should diminish during
the evening with loss of heating.

Moisture increases from the south within the upper high which
flattens some across CO Wednesday afternoon.  H7-H5 layer specific
humidity increase to around 6-7 J/kg across the mountains and
valleys with PWATs increasing to around or slightly above an
inch.  This is about 2-3 standard deviations above normal.  This
will lead to more widespread thunderstorms this day with better
chances for heavy rain and stronger thunderstorm strengths. Gusty
outflow winds, small hail, heavy rain and lightning will be the
primary storm risks and will need to monitor burn scars closely as
storm motions will be slow with light flow aloft under the ridge. A
little better shear will be in place farther east, especially
Wednesday night as the low level jet increases.  Models are in good
agreement with developing a thunderstorm cluster across western NE,
into NW KS Thursday night along and north of the cold front.
Thunderstorms could linger into the night across far eastern areas
with the increasing low level jet, though main track of any MCS
appears to stay to the east.  Temperatures may cool a couple degrees
with more convective cloud cover Wed, but overall it will still be
well above normal.

Upper ridge flattens out for Thursday.  Specific humidities stay
fairly high (6-7 g/kg) and spread eastward, so another day of
scattered to numerous showers and thunderstorms can be expected
with heavy rainfall possible with the stronger storms. Deep layer
shears may be strong enough for a few strong to severe storms
depending on low level moisture and resultant CAPE.  Gusty winds
over 60 mph may be the primary risk with these.

Drying starts to spread in for Friday out west as an upper trough
swings by to the north. However this also sends a cold front into
the southeast plains by Friday evening with post frontal upslope
flow. Overall a cool down is expected, especially for weekend
behind the front. Long range models differ with how much low level
moisture spreads in behind the front and resultant instability which
will affect thunderstorm chances.  The GFS suite keeps
the plains more capped with highest pops across the southeast
mountains where upslope flow and surface heating will trigger a
round of afternoon thunderstorms capable of producing heavy
rainfall and a few strong to severe storms especially on Sat. EC is
a little more moist across the plains and suggests a better chance
for thunderstorms to spread eastward across the plains. This is
still a ways out so will need to monitor how this evolves as we
get closer. -KT

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 518 AM MDT Mon Jun 24 2024

VFR conditions are expected at all three TAF sites, KCOS, KPUB, and
KALS, for the next 24 hours. Isolated showers and weak thunderstorms
are possible in the vicinity of all three stations this afternoon
and this evening, mainly between 21Z and 02Z. Though confidence in
any storms moving directly over any station is low at this time,
gusty outflow winds could directly impact the terminals today.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon today to 6 PM MDT this evening for
COZ083>086.
Heat Advisory from 11 AM to 7 PM MDT Tuesday for COZ083>086.

&&

$$

SHORT TERM...EHR
LONG TERM...KT
AVIATION...EHR