Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 261746
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1146 AM MDT Tue Mar 26 2024

.KEY MESSAGES...

- Scattered convective showers will develop this afternoon, with
  some rumbles of thunder and gusty winds possible.

- Most precipitation dissipates tonight, with isolated snow
  showers still expected over the mountains.

- Longer period of near critical and critical fire weather
  conditions expected beginning on Thursday and lasting through
  Sunday

- Spring system to bring snow over the higher elevations on
  Sunday through Tuesday - still uncertain for the lower
  elevations

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 400 AM MDT Tue Mar 26 2024

Today: Tuesday will bring a Spring-esque day to south central and
southeastern Colorado, with afternoon convective showers, despite a
cool day. Synoptically, northwesterly flow will prevail, though an
embedded shortwave wave will push southeastward over the region. The
northwesterly flow will help keep orographic forcing in place, while
the wave brings an uptick in broader synoptic forcing/support. The
rise in forcing will allow for scattered precipitation to develop
along the mountains during the early afternoon, and the overall
synoptic support will help them to survive being pushed off of the
higher terrain and across the valleys and immediate I-25 corridor
during mid to late afternoon. Precipitation across the mountains and
valleys is expected to remain snow throughout the day. Precipitation
generally around and along the I-25 corridor is expected to be rain
and rain/snow mix given warmer temperatures across this area. Given
colder temperatures aloft with the shortwave, and therefore
steepening lapse rates, modest MUCAPE is expected to materialize
during the afternoon, with values ranging around 100-400 J/kg. This
instability will help showers become convective in nature, and some
lightning and rumbles of thunder will be possible with any stronger
precipitation cores that develop. Along with that, minor DCAPE will
also be present over the region, which will allow for gusty outflow
winds of around 30-40 mph with any of the more organized
precipitation cores. As for temperatures, a cool and mild day is in
store for the area. Temperatures will start to rebound to warmer
values, though the slightly unsettled pattern and cloud cover will
limit heating. Given that, the plains will warm into the 40s, the
valleys rising into the 30s, and the mountains reaching into the 10s
to mid 20s.

Tonight: Tuesday night will bring a relatively quieter period of
weather to the region. Northwesterly flow will continue over the
area, while the shortwave from the day will be drifting to the
southeast. Broader forcing will lessen as the wave exits the area,
but orographic forcing will continue as northwesterly flow persist.
In addition to all of that, instability will start to wane as
diurnal warmth decreases. With all that said, any precipitation
present will start to lessen in coverage and intensity throughout
the evening, with only isolated light snow showers remaining over
the mountains overnight given the orographic forcing still in place.
Looking at temperatures, a chilly night is expected, though again
warmer than recent nights. With the lack of northerly winds
reinforcing colder air, and the presence of some clouds, low
temperatures will also rebound to warmer values, relatively
speaking. With that all said, the plains will cool into the 20s, the
valleys sinking into the 10s to low 20s, and the mountains dropping
into the single digits.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 400 AM MDT Tue Mar 26 2024

Wednesday :

The broad trough that has been impacting souther southern Colorado
the last few days finally exits at the end of the day on Wednesday.
Before is completely leaves the region it`ll produce scattered snow
showers over the central mountains. There is a little bit of
instability in the air, so the snow showers that do develop will
have moderate to heavy snowfall rates. There may be a pop-up shower
over the eastern plains, but overall a dry day is expected over the
lower elevations. High temperatures will be in the 40s to 50s over
the plains and the 30s to 40s over the mountain valleys. Low
temperatures overnight will be in the 20s over the plains and the
teens to 20s over the mountain valleys.

Thursday and Friday:

A brief ridge develops over Colorado late Wednesday through Thursday
bringing warmer temperatures and dry conditions throughout the day.
By midday the ridge axis will already be east of Colorado and
southwesterly flow will replace it. A jet streak starts to propagate
over the western portion of the state by midday. The jet aloft is
expected to create some gusty wind over the San Luis Valley and over
the gap flow prone areas such as the exit of the Big Horn Sheep
Canyon in Fremont County and the Spanish Peaks region. Wind gusts of
up to 30 to 35 mph are expected. The relative humidity values are
above 20% at this time, so no critical fire weather conditions are
expected at this time - we`ll need to keep monitoring however.

Expect the same thing on Friday but more widespread gusty winds
across much of the region. Relative humidity values will be closer
to that 15% threshold over the plains - so this will be our first
good shot at critical fire weather conditions. The central mountains
will start seeing some snow showers once again on Friday afternoon.

Saturday through Monday:

The best set up for meteorological fire weather conditions will be
Saturday and Sunday. As a low pressure system propagates over
southern California its associated jet streak (the polar jet) merges
with a sub-tropical jet enhancing the wind speeds that are oriented
from the southwest to northeast over Colorado. This is a great
orientation from downslope winds off our mountains. So it does seem
like we`ll have a warm, dry, and windy weekend with critical fire
weather conditions being the biggest concern.

On Monday concerns shift from fire weather to winter weather issues
once again, but right now the data shows two closed lows interacting
with each other 6 to 7 days out - which just might have the lowest
amount of forecast confidence out there. Either way, currently there
is fairly high confidence for snow over the mountains and if what I
am seeing today persists, the strong southwesterly flow and small
amounts of instability in the atmosphere will make for a snow band /
snow squall set-up for the lower elevations. Let`s iron out the
details before we sound the alarms, though.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1134 AM MDT Tue Mar 26 2024

At KCOS and KPUB, VFR the next 24 hrs, with a vcsh at both sites
from 20z until 02z-03z as showers move off the mountains. Could
see a brief period of IFR cigs/vis under any heavier showers,
and even a brief tsra is possible, bringing gusty winds to 30
kts, though will monitor radar trends before adding any mention
to the taf. Precip ends this evening after 03z, with VFR cigs
overnight. On Wed, VFR expected.

At KALS, already seeing some convection on radar across the
valley, and will include a vcsh mention for most of the
afternoon into early evening. Also have a tempo group from
20z-24z for MVFR conditions as showers strengthen, and there is
a low risk for a brief period of IFR with a tssn, though won`t
explicitly mention in the taf at this point. Convection ends
after 03z, with VFR cigs overnight. On Wed, VFR expected.

&&

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

&&

$$

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


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