497
FXUS65 KPUB 172039
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
239 PM MDT Sat Aug 17 2024

.KEY MESSAGES...

-  Hot again Sunday, with an upturn in thunderstorm chances, especially
   across the mountains and I-25 corridor.

- Cooler with an uptick in heavy rain producing thunderstorms
  for Monday and possibly Tuesday with a few strong to near
  severe across the SE plains/I-25 corridor.

- Heating up again with thunderstorms possible most days,
  greatest coverage over the mountains.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 236 PM MDT Sat Aug 17 2024

Currently...Better moisture and instability have remained over UT
and wrn CO this afternoon, with thunderstorm activity as of 230 pm
staying west of the Continental Divide. Have also seen an isolated
storm develop over the ern plains of Colorado north of I-70 in Kit
Carson County along the wrn edge of deep instability pool over nw
KS, though expect this activity to remain north of the CWA. Building
upper ridge has brought warmer temps to much of the region this
afternoon, and locations along the lower Arkansas Valley were around
100 degf as of 2pm.

Tonight...HRRR suggest wrn CO convection eventually reaches the
central mountains from late this afternoon into this evening, with
more isolated activity farther south over the La Garitas/San Juans.
Valleys and eastern mountains could see a weak storm this evening as
well, though rainfall amounts at lower elevations will be light at
best. Activity ends at most locations after midnight, though a few
lighter showers could linger into early Sunday morning over the
higher peaks of the central mountains.

Sunday...Upper ridge slips slowly eastward, allowing deeper moisture
to gradually increase across the area by afternoon. Most models show
a fairly substantial upturn in afternoon convection as a result,
with a few storms reaching the I-25 corridor/sern plains. 0-6km
shear (20 kts) and modest CAPE (1000 J/KG) suggest limited severe
threat Sunday, though brief downburst/gusty near severe wind may be
possible with any stronger storms. If convection can bridge the gap
on the plains and reach deeper instability/greater shear near the KS
border late in the day, severe threat would increase, especially
Kiowa/Prowers Counties. Before storms develop, max temps Sunday look
hot once again, with widespread 90s to near 100 lower elevations,
80s to low 90s valleys and lower mountain slopes.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 236 PM MDT Sat Aug 17 2024

Upper ridge remains anchored over the southern Rockies through the
period with the ridge axis gradually shifting eastward with time
through next week.  This will mean westerly flow aloft will
gradually become more southwesterly putting southern CO more
directly under the monsoon fetch by mid week. Precipitable
waters increase into the 100-150% of normal range for Monday
with post frontal upslope flow spreading 50s to lower 60 dew
points into southeast CO by afternoon. Shortwave rounding the
top of the upper ridge across CO on Monday will provide a
trigger for widespread afternoon and overnight showers and
thunderstorms which will develop over the mountains by afternoon
and spread eastward with time. Models suggest a convective
cluster will develop somewhere along the southern I-25 corridor
region and move east southeastward through the evening with the
potential for heavy rainfall and flash flooding for vulnerable
locations. With the potential for up to 2000+ J/kg of CAPE and
respectable deep layer shears around 30 kts, a few strong to
severe storms can`t be ruled out with large hail and damaging
winds the primary concerns. Storms could linger past midnight
out across far eastern areas until the MCS pushes eastward into
KS overnight.

Recycled moisture for Tuesday will lead to another round of
afternoon and evening thunderstorms with heavy rainfall the primary
risks.  These may stay focused across the mountains and adjacent I-
25 corridor as forecast soundings look more capped across eastern
areas Tuesday afternoon, and forcing aloft looks weaker.

Flow aloft becomes more southwesterly for mid to late week with a
continued fetch of monsoon moisture over the region. Precipitable
waters remain around 100-150% of normal each day with deepest
moisture fetch across the Continental Divide, while lee
troughing on the southeast plains drops back surface dew points
some. There will still be a shot for heavy rain each day, but
focus would trend westward across the eastern San Juans and
Continental Divide region into next weekend. Meanwhile,
temperatures should return to above normal with some near 100
degree readings across portions of the southeast plains. -KT

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1119 AM MDT Sat Aug 17 2024

VFR conditions are anticipated during the next 24 hours at all
3 taf sites, KPUB, KALS and KCOS. Winds at KCOS and KPUB have
been slow to switch to the usual upslope this morning, but most
guidance suggests a shift back to s-se by 19z-20z. Overnight
and Sunday morning, winds will be light and diurnally driven.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...PETERSEN
LONG TERM...KT
AVIATION...PETERSEN