049
FXUS65 KPUB 262043
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
243 PM MDT Fri Apr 26 2024

.KEY MESSAGES...

 - Heavy snow spreads into the mountains tonight through
   Saturday, with heavy rain possible for El Paso county.

 - Critical Fire Weather conditions expected for Baca county
   with one or two strong storms possible for the southeast
   plains north of highway 50 Saturday afternoon.

 - Showers expected across the region Saturday night, with snow
   showers for higher elevations and rain and rain/snow mix for
   lower elevations.

 - Showers blossom again Sunday afternoon, before quikcly
   dissipate Sunday night.

 - Quieter weather expected for much of next week, with singals
   for the possiblility of more unsettled late next week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 241 PM MDT Fri Apr 26 2024

A complex weather scenario with a variety of weather hazards will
impact southern CO over the next 24 hours as a closed low taking
shape over the Great Basin moves through the 4 Corners region
tonight and lifts into eastern CO on Saturday.  As upper level
difluence overspreads the area, rain and snow showers will spread
into the mountains this evening with snow levels dropping after
midnight as colder air aloft moves in.  First wave of
WAA/overrunning will generate widespread rain/snow showers and
embedded thunderstorms along the I-25 corridor, mainly north of
highway 50 after midnight, concentrating heaviest QPF across the
Pikes Peak region Saturday morning before lifting northward.
Snowfall totals will be heavily reliant on snow levels and
temperatures in the higher res models have come down in most recent
runs.  Teller county is of greatest concern as temperatures drop to
around or slightly above freezing towards morning with snow levels
dropping to around or a little below 8kft.  Have upgraded winter
storm watches with winter storm warnings though expect quite a
gradient by elevation with most impacts above 8500-9000 feet where
some areas will receive over a foot of snow, and closer to 30 inches
on the top of Pikes Peak.  Palmer Divide could see a rain/snow
change over Saturday morning with some visibility impacts during the
heavier snow, but the ground warmth should limit accumulations to up
to 3 inches on grassy surfaces.  High res models have been wavering
these details from run to run, so this will need to be watched
closely.  Meanwhile, southerly flow upsloping into the Palmer Divide
overtop of the frontal boundary will mean some fairly healthy
rainfall amounts across the remainder of El Paso county with up to
1.5 inches of rain over the 36 hour period.  This will likely lead
to some enhanced runoff but within bank flows given the dry
antecedent conditions.  Other areas with impacts from heavy snow
will be the Upper Arkansas River valley with elevations above 8500
feet seeing snowfall totals in the advisory range, and warning
numbers (around 1 foot or more) across the higher elevations above
11kft. A mix of warnings and advisories have been posted for Lake
and Chaffee county.

All other headlines remain unchanged.  Did bump the start time a
little later for the southeast mountains with the heaviest spreading
in after midnight.

Across the plains, the surface low/surface boundary will lift back
northward with dry, windy southwest flow overspreading the southeast
corner of the state.  Critical fire weather conditions will be met
across Baca county and a Red Flag Warning has been issued.  North of
the northward advancing boundary, there will be a ribbon of
instability and the potential for one or two strong to severe
storms, particularly north of highway 50 where HREF members show
some helicity streaks with thunderstorms as they lift northward into
more favorable deep layer shear and SRH in the 100-200 m2/s2.
Marginally severe hail looks to be the main risk as parameters look
more favorable to the north of the CWA.  But trends have been
pointing to a slower advancing warm front, so some of our northern
counties, Kiowa, Crowley and perhaps even NE El Paso if sufficient
CAPE can be realized, may become under increasingly favorable
conditions for a severe storm or two.  Can not rule out an brief
weak tornado immediately behind the front if residence time within
narrow axis of instability is sufficient. -KT

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 241 PM MDT Fri Apr 26 2024

Saturday Night: Saturday night will bring the tale end of more
impactful weather as a large trough starts exiting the south central
and southeast Colorado area. Throughout the night, the trough will
be pushing eastward, and while forcing will start to lessen heading
into Sunday morning, synoptic forcing and orographic forcing will
continue to some extent during this timeframe. With the forcing
still in place, and moisture still residing over the region, showers
are expected throughout the overnight hours, with the heaviest
showers expected along the mountains. The snow level will hover
around 7,000 feet throughout the night. Areas generally around and
above this value are expected to remain all snow, while areas
generally around and below this value are expected to be a rain to
rain/snow mix. As mentioned though, forcing will be lessening
overnight, and in response to that, any showers across the area will
decrease in coverage and intensity heading into Sunday morning.
Looking at temperatures, a mild night is expected, as clouds help to
limit optimal cooling, keeping the region at to slightly above
seasonal values for overnight.

Sunday: Some active weather continues for the end of the weekend. A
shortwave will swing around the western periphery of the exiting
larger trough. While this wave won`t be as strong or organized, it
will still bring an uptick in forcing, especially during the
afternoon and evening. Given this wave, showers will again bloom
over the region during the day, with the greatest coverage of
showers during the afternoon and evening hours. Snow is anticipated
for the mountains, with rain expected for the lower elevations and
most of the valleys. There is some minor instability that will be
present during the afternoon, so some rumbles of thunder and brief
periods of heavier precipitation will be possible. As this wave
treks eastward Sunday evening and night though, precipitation
present across the area will lessen in coverage and intensity from
west to east. As for temperatures, a slight rebound to warmer values
is expected to near seasonal values, though daytime clouds will
hinder warming potential.

Monday - Thursday: For the rest of the long term period, relatively
quiet weather is expected for south central and southeastern
Colorado. Flow will become predominantly westerly over the region,
which ensemble model guidance are in decent agreement on. Given the
lack of major forcing with this flow pattern, dry conditions are
expected, with the exception of isolated light showers along the
mountains given weak orographic forcing. With that all said, there
are hints of a more unsettled and meridional flow pattern developing
during the midweek week period and into the later half of the week,
which could bring more precipitation chances to the area. Confidence
is low though at this time on how, if at all, this more wavy pattern
will influence the region. Temperatures during this period will
continue to warm, with many parts of south central and southeastern
Colorado warming to above seasonal values for late April to early
May.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 241 PM MDT Fri Apr 26 2024

Lowering cigs can be expected overnight as conditions at KCOS drop
into the MVFR to IFR range from 06z to 12z as widespread SHRA and
TSRA develop overnight and continue through the morning. KPUB will
also see a round of SHRA/TSRA around/after 12z with MVFR cigs/vis.
KALS will see a chance for SHRA between 06z and 12z with brief MVFR
conditions before improving after 12z.  Conditions should return to
VFR for KALS and KPUB by the afternoon with MVFR to VFR for COS.
Surface winds will decrease and shift out of a light northerly
component for KCOS and KPUB tonight.  Gusty southwest winds at KALS
will diminish this evening but stay southerly overnight before
increasing again Saturday morning. KPUB and KCOS will see
predominantly northerly winds Saturday gusting to around 30 kts in
the afternoon. -KT

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 6 AM MDT Sunday for COZ058-060.
Winter Weather Advisory from 6 PM this evening to 6 AM MDT
Sunday for COZ059-061-063.
Winter Weather Advisory until 6 AM MDT Sunday for COZ066-068-
073.
Winter Weather Advisory from 9 PM this evening to 6 AM MDT
Sunday for COZ076.
Winter Storm Warning from 9 PM this evening to 6 AM MDT Sunday
for COZ081.
Winter Storm Warning from 6 PM this evening to 6 AM MDT Sunday
for COZ082.
Red Flag Warning from noon to 7 PM MDT Saturday for COZ237.

&&

$$

SHORT TERM...KT
LONG TERM...SIMCOE
AVIATION...KT