957
FXUS65 KPUB 191025
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
425 AM MDT Thu Sep 19 2024

.KEY MESSAGES...

- Another dry day with frost possible again in the San Luis
  Valley tonight.

- Warm and breezy conditions for Friday, with spotty critical fire
  weather conditions and isolated convection across the plains.

- High confidence (70-90%) in a cool and wet weekend with
  widespread rain and mountain snow likely Saturday through
  early Sunday.

- Lower confidence (10-20 percent) in stronger storms across the
  SE Plains on Saturday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 421 AM MDT Thu Sep 19 2024

Cool front is dropping southward through the plains, evident in area
radars early this morning.  This will bring some minor cooling
(perhaps a degree or two cooler than yesterday) across the plains as
winds shift out of the east then southeast by afternoon.  Out west,
little change is expected from yesterday with dry and warm fall
temperatures returning.  Winds will become breezy in the afternoon,
especially in and near the mountains, but gusts overall should stay
under 25 mph which should limit any critical fire weather concerns
in spite of low afternoon humidity values across the lower
elevations. There will be a wave of high cloudiness lifting
northward across the area this afternoon and evening, but the
forecast area will remain dry. Clear skies overnight tonight will
lead to another crisp fall morning across southern CO, especially
mountain valleys.  We could see another frost for the San Luis
Valley, but with Frost Advisories already in effect this morning,
will let later shifts issue additional headlines if necessary.
-KT

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 421 AM MDT Thu Sep 19 2024

Friday-Friday night...Latest models are in good agreement on slowly
increasing southwest flow aloft across the Rockies through the day on
Friday, as a seasonably strong upper low digs across the West Coast
and into Western Arizona by 00Z Saturday, which is a tad slower and
a tad further west than was forecasted 24 hours ago. Southwest flow
induces lee troughing across the plains on Friday, with breezy south
to southwest winds again leading to some spotty critical fire weather
conditions, mainly along and west of the I-25 Corridor, with southerly
flow expected to increase low level moisture further east across the
plains. This will lead to the potential for a few afternoon and evening
showers and thunderstorms, with NBM mean CAPE of 200-600 j/kg across the
far southeast plains. Friday also remains the last day for above normal
temperatures for a while, with highs in the mid 80s to mid 90s expected
across the plains, and mainly in the 60s and 70s across the higher terrain.

Saturday-Sunday...Operational and ensemble model data are coming into
much better agreement with timing and location of the upper low across
Western Arizona lifting out into the Four Corners region Saturday
afternoon. This system remains progged to continue out across south
central Colorado Saturday evening before continuing into northeastern
Colorado by Sunday afternoon.

With that said, increasing moisture and uvv ahead of the system will
develop rain showers across south central Colorado by mid morning, with
the potential for waa showers developing across the southeast Plains
through the late morning and early afternoon. The latest NBM data
indicates mean CAPE across the plains of 400-900 j/kg with enough
shear for the development of supercells. However, with the slower
ejection of the upper low, there may not be enough uvv or instability
to develop strong storms across the southeast plains. Time will tell.
The latest SPC Day 3 outlook has a marginal risk across much of eastern
New Mexico, with the marginal risk inching into southeastern portions of
Las Animas county into southwestern portions of Baca county.

The expected movement of the upper low will lead to widespread precipitation
across south central Colorado spreading north and east across the eastern
eastern and plains Saturday afternoon and evening before precipitation
lifts north and east into northeastern Colorado Saturday night and Sunday,
with some wrap around precipitation continuing across the Pikes Peak and
Palmer Dvd region through the day Sunday. Latest qpf has increased across
the area with 1/2 to 1 1/2 inches possible by Sunday morning, greatest
amounts over and near the higher terrain along and north of Highway 50,
as will as across the far southeast plains. Snow levels look to lower
to between 10-11K ft Saturday night, with latest model data supporting
several inches of snow across the higher peaks (generally above 12K
ft), across the Central Mtns into the Pikes Peak region by Sunday
morning. Later shifts may need to go with early season winter weather
highlights for the highest zones. While precipitation totals remain
in flux with the eventual track of the passing system, temperatures
will definitely cool to well below seasonal levels through the weekend,
with coolest day expected to be Sunday, with highs in the 60s across
the lower elevations and mainly in the 40s and 50s across the higher
terrain, save for 30s at the peaks.

Monday-Thursday...A generally cool and unsettled northwest flow pattern
remains in the offing for early next week. This will keep chances of
precipitation, especially over and near the higher terrain, along with
temperatures at and below seasonal levels into the middle of the work
week, with warmer and drier weather returning into the end of next
week, as upper level ridging builds back across the Rockies.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 421 AM MDT Thu Sep 19 2024

VFR conditions expected over the next 24 hours.  North winds at KCOS
and KPUB this morning will shift around from the east then southeast
in the afternoon but speeds should stay under 20 kts.  Light winds
at KALS will increase out of the southwest and gust up to 25 kts in
the afternoon. Winds will become light and diurnally driven tonight
at all 3 terminals with some passing high cloudiness from late
afternoon through the evening. -KT

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 8 AM MDT this morning for COZ069>071.

&&

$$

SHORT TERM...KT
LONG TERM...MW
AVIATION...KT