Peyton, Colorado Weather Forecast Discussion

580
FXUS65 KPUB 092109
AFDPUB
Area Forecast Discussion
National Weather Service Pueblo CO
Issued by National Weather Service Denver CO
309 PM MDT Tue Sep 9 2025
.KEY MESSAGES...
- Another round of gusty thunderstorms this afternoon/evening,
  with some strong to severe storms possible along the eastern
  border late.
- Daily storms continue over the mountains into midweek, with
  lower chances over the plains.
- Greatest coverage of showers and storms Friday, with the
  highest chances and locally heavy rain threat over the
  mountains.
- Drier again into the weekend but a little cooler.
&&
.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 307 PM MDT Tue Sep 9 2025
Currently...Upper trough over the West Coast with the low center
over western OR was producing brisk southwest flow aloft across
the Four Corners, with moisture advection for the western half of
CO. Isolated showers and thunderstorms have developed across the
higher terrain this afternoon, with a focus area over the central
mts. Temps have warmed into the 70s and 80s for most locations as
of 1 PM, with near 90F for the far eastern plains.
Tonight...Upper low trough will dig south through the night, with
the upper low center pushing onshore across northern CA. Southwest
flow aloft will persist, while the upper ridge over CO gradually
slides to the east and the ridge axis reaches the eastern CO border.
Current convection across the higher terrain is expected to gradually
drift across the I-25 Corridor late this afternoon, but latest runs
of the HRRR and HREF are indicating potentially stronger storms
further east later tonight, in the 9 PM to midnight timeframe and
possibly lasting longer. Due to lee troughing with southerly surface
winds near the eastern border, current dewpoints in the mid 50s
indicate the best llvl moisture there. Model CAPE of 1500-2000j/kg
and bulk shear of 35-45 kts right along the CO/KS border further
supports the potential for stronger storms out east late tonight,
and latest SPC severe wx outlook has painted a Slight area for
severe storm potential dipping down into Kiowa Co, while a Marginal
remains all along the eastern border. Main threat from convection
this afternoon and evening will be gusty winds to 45 mph, but the
stronger storms will potentially produce 55-60 mph gusts, hail up
to one inch in diameter and periods of moderate to heavy rainfall.
Plan on overnight lows in the 40s across the high valleys and 50s
across the plains.
Wednesday...The upper trough initially makes a push onshore but
then remains somewhat static, with more of a south-southwest flow
aloft across the Four Corners and Great Basin regions. Convection
is expected to fire over the higher terrain by midday once again,
but storm motion will likely be a bit more to the northeast while
models are indicating less shear and slightly less CAPE to work
with. Another round of gusty storms will be the main threat, and
SPC has painted the entire area under General for thunder. Plan on
one more day with highs in the 70s to around 80F for the high
valleys, and 80s to around 90F for the plains.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 307 PM MDT Tue Sep 9 2025
Wednesday Night and Thursday:
The upper level low located over the western United States will
continue to emit weak waves over southern Colorado which will
keep thunderstorms going for 1 to 2 hours after the beginning of
the long term forecast period (6PM on Wednesday).
Environmentally, there isn`t much to talk about since any CAPE
over the region will be on the decrease as we lose heating. The
storms are pegged to develop over the southern I-25 corridor,
which hosts CAPE values of less than 500 J/kg with a hefty
amount of CIN. Main hazard will be gusty winds of up to 40 MPH
as the storms dissipate and the cores drop. For Thursday, the
closed low slides slightly closer to Colorado which will emit a
wave that is a little strong than that on Wednesday. The main
vorticity stream extends SW to NE from the San Luis Valley
towards the Pikes Peak Region, which is where the convection is
expected to develop. Once again, the instability is lacking with
values less than 1000 J/kg, so the main risks will be gusty
thunderstorm outflow winds with gusts up to 50 MPH, small hail,
and lightning. Showers and thunderstorms would continue
overnight over the Continental Divide.
Friday:
Friday is the day that the closed low finally gets caught up in
the upper level flow and begins to make its exit out of the
western half of the United States. The strongest waves will pass
overhead as the primary trough propagates SW to the NE. The main
energy will be focused over the West-Northwest portion of
Colorado, which is where the majority of the convection will
develop - so expect widespread thunderstorms over the mountains
and mountain valleys. The highest CAPE values will be near the
New Mexico border in the San Luis Valley, but those values are
at most around 800 J/kg. However, the CAPE is long skinny CAPE,
meaning that the sounding is pretty saturated throughout the
entire layer, which makes sense since the source of moisture
with this low-pressure system originates from the Pacific. I
think there will be some sneakily heavy rainers that form from
these storms and flooding and flash flooding needs to be
monitored. Lingering showers will continue through the early
morning hours on Saturday.
Saturday through Monday:
Drier conditions are expected as the drier airmass and the
height rises from the backside of the passing low-pressure
center develop over southern Colorado. Perhaps we`ll see an
isolated stronger thunderstorm on the east side of the dryline
near the Kansas border, but the rest of the region will be warm
and dry. The same sentiment exists on Sunday, as well. I suppose
one thing we`ll have to worry about are fire weather conditions
on both Saturday and Sunday, as the upper level pattern will be
SW flow over the region, which tends to indicated elevated fire
weather concerns.
&&
.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 1134 AM MDT Tue Sep 9 2025
VFR conditions anticipated across much of the forecast area over the
next 24 hours, including the three main TAF sites of KCOS, KPUB and
KALS. Showers and thunderstorms will fire over the higher terrain by
18z-19z, gradually spreading across the I-25 Corridor affecting KCOS
and KPUB in the 23z-00z time frame. Maintained PROB30 wording for -
TSRA and variable gusts to 30 kts for those two sites, with
intermittent MVFR conditions possible.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...MOORE
LONG TERM...WFO Pueblo
AVIATION...MOORE

NWS PUB Office Area Forecast Discussion