107
FXUS65 KPUB 170925
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
325 AM MDT Sun Aug 17 2025

.KEY MESSAGES...

- Upper ridge shifts slightly eastward today, bringing drier air
  and lower chances for thunderstorms to the region. &&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 325 AM MDT Sun Aug 17 2025

Today and Tonight...Upper-level ridge moves east into the plains,
with main plume of higher moisture shifting south and east of the
region. As a result, we should see a general drop off in
thunderstorm activity across the area as moisture/instability
decrease, with mainly isolated, high based storms over the
mountains. Sliver of slightly higher instability (CAPE 500-1000
J/KG) possible over the far sern plains where se surface winds allow
for slightly higher dewpoints to linger, and CAMs hint at a few
storms over ern Las Animas/Baca Counties from late afternoon into
early evening, before activity dissipates 02z-03z. Deep layer shear
looks weak, so main risks will be gusty outflow winds and lightning
with any stronger storms. Sunday`s high temperatures will drift
upward a couple degf over the mountains and valleys, while readings
on the plains stay withing a degf or two of Saturday`s numbers.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 325 AM MDT Sun Aug 17 2025

Monday and Tuesday:

Showers and thunderstorms are expected to develop Monday afternoon
with some of the storms could be strong to severe over the Pikes
Peak Region and over and near the Raton Mesa in Las Animas County.
The primary hazards I am concerned about are gusty outflow winds of
up to 40-50 MPH. LCLs are around 10kft, so the precipitants have
very far distance to fall in a dry environment (more evaporation ->
evaporational cooling -> stronger downdraft). CAPE values are
expected to be below 1000 J/kg and deep shear values are around
30kts - not terribly concerned about organized convection producing
hail. Lingering weak thunderstorms will last through around
midnight, but minor impacts are expected.

Tuesday is expected to be the last day for isolated to scattered
thunderstorms before a brief dry spell occurs. The limiting factor
to how strong convection gets will be how much moisture from the
eastern plains is advected towards the plains-mountains interface.
Currently, the majority of guidance has sub 1000 J/kg of CAPE along
the eastern mountains and the I-25 corridor, but the aggressive NAM
has 1500-2000 J/kg of MUCAPE (which I do not believe). Overall,
another I think the main hazards will be gusty outflow winds from
high based thunderstorms along the I-25 corridor.


Wednesday through Saturday:

The upper level high sets up over the four corners region of the
desert southwest and begins to advect moisture from the eastern
Pacific / Baja California towards southern Colorado. While we wait
for that moisture to reach Colorado, we`ll have two dry days with
Wednesday and Thursday. The trend has been having an uptick in storms
on Thursday, but the brunt of the moisture will arrive on Friday.
Some persistent signals amongst longer term guidance is suggesting
heavy rain over the mountains and the I-25 corridor on Friday and
Saturday - perhaps this is mountain flash flood event beginning to
show its eyes for the end of next week and into the weekend.
&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 325 AM MDT Sun Aug 17 2025

VFR conditions anticipated across the forecast area over the next 24
hours, including the three main TAF sites of KCOS, KPUB and KALS.
Surface winds are forecast to be diurnal in direction and generally
under 12 kts. Low chance (10 percent) of some briefly gusty outflow
winds from distant convection at all sites 21z-01z), though with
very sparse coverage of storms, won`t include in any tafs at this
point.

&&

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

&&

$$

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