760
FXUS65 KPUB 060540
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1140 PM MDT Sun May 5 2024

.KEY MESSAGES...

- High winds will spread across the region tonight through
  Monday morning.

- Brief round of wind driven snow expected for the Continental
  Divide late tonight through Monday morning.

- Critical fire weather conditions will be widespread for the
  San Luis Valley and portions of the plains during the
  afternoon and evening hours on Tuesday and Wednesday.

- Very strong and gusty winds (near High Wind Warning criteria
  for some areas) are expected on Tuesday. Blowing dust will be
  possible across the lower elevations.

- A few showers and high elevation snow showers will be possible
  for areas mainly north of Highway 50 on Tuesday through
  Wednesday.

- Scattered showers and thunderstorms, with high elevation snow,
  will be possible on Thursday through Saturday, along with
  cooler temperatures.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 241 PM MDT Sun May 5 2024

Upper low over NV/UT will move eastward across northern CO tonight
and into western NE by Monday afternoon.  This will send a brief
round of wind driven snow into the mountains along the Continental
Divide tonight before snow diminishes from south to north Monday
morning. Still getting around 4 to 8 inches across the higher peaks
and passes with the potential for brief hazardous travel impacts
during the overnight hours.  Have issued a short duration winter
weather advisory to highlight this potential.

A bora cold front will cross the mountains late tonight into Monday
morning spreading a round of high winds across the southeast
mountains and into portions of the I-25 corridor around dawn on
Monday.  Gusts in the 60 to 75 mph range will be possible as the
front crosses the mountains and strong downward forcing briefly
transports higher momentum aloft to the surface.  It will remain
windy through the morning, but the high wind potential looks to
diminish rapidly after 15z.  Will upgrade the High Wind Watches to
High Wind Warnings with the afternoon package. There is the
potential for high wind gusts to impact portions of western Pueblo
and southwest El Paso as well though coverage looks limited to
locations west of I-25 and close to the mountains.

Very dry air behind the front will overspread southern CO on Monday
resulting in a return of critical fire weather conditions across
southern CO for locations where fuels are deemed critical by land
management agencies.  This will be confined to the San Luis Valley,
the lower slopes of the Wets and Sangre De Cristo Mountains, the Wet
mountain valley, and the Comanche grassland locations of Otero,
eastern Las Animas and Baca counties where greenup has been delayed
due to dry conditions this spring.  However, given the magnitude of
the winds on Monday, any activities which could start a wildfire is
discourages as any fuel sources available to burn could become
volatile with such strong winds.

Otherwise, temperatures will remain mild, though cooling to a little
below climo for Monday behind the front.  Winds tail down in the
afternoon though it will still remain windy with critical fire
weather conditions.  Think any blowing dust will be confined to the
morning hours with the strongest winds associated with the frontal
passage. -KT

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 241 PM MDT Sun May 5 2024

Monday night through Wednesday...

After passage of the bora front Monday night, there will be a lot of
forward shear on the backside of the front within the westerly flow
at the 700 mb level moving over the entire CWA on Tuesday, with some
50 kt pennants showing up over the southern I-25 corridor with some
of the deterministic models. This is going to translate to very
strong and gusty winds down to the surface, which could occasionally
reach High Wind Warning criteria over certain areas by later in the
day on Tuesday. Along with this will be blowing dust possible across
the lower levels, as well as critical fire weather conditions for
the San Luis Valley, and portions of the plains by later in the
afternoon and through the early evening once RH values tank. The
winds look to become the strongest right around peak heating in the
middle of the day once there is the best mixing present. Although,
confidence of persistent High Wind Warning criteria is not high at
this time, given that cross sections display only forward shear, and
thus deep mixing would be the only forcing that could get these
stronger winds down to the surface.

Stronger winds will be more likely across the higher elevations
of the Sangre de Cristo Mountains, which appear at this time to
have a higher probability of needing a High Wind Warning vs
other mountains. Again, there is still some uncertainty of
this, depending on the position of the longwave trough and where
the strongest 700-500mb flow will be. The San Luis Valley will
also be another area in question for needing a potential High
Wind Warning on Tuesday, if deep layer mixing does occur. With
winds as the main concern, precipitation will be generally
sparse on Tuesday, and more or less confined to areas north of
Highway 50. The northern Sawatch and Mosquito Ranges will be the
locations most likely to receive any measurable precip, with a
few inches of snow possible. Downsloping winds will also
adiabatically warm up the lower levels, with highs topping out
in the upper 70s to low 80s across the plains. The higher
terrain will be relatively cooler, and either at, or slightly
below, the seasonal average for this time of year.

By Wednesday, a frontal boundary will move through with winds
shifting more out of the northerly direction over the plains. This
will help to allow for colder air advection, with temperatures being
anywhere around 10 to 15 degrees cooler for highs. Strong and gusty
winds will continue to be out of the more west to northwesterly
direction over the higher terrain, yet not as strong. There will
still be some showers possible over the central mountains, and also
for areas of the Pikes peak Region (PPR), Ramparts, and Palmer
Divide. There will still be widespread critical fire weather
conditions over the San Luis Valley, although the northerly flow for
the plains will help to mitigate fire concerns over the plains,
although there could still be some areas which are vulnerable due to
critical fuels over eastern Las Animas County that may need fire
weather highlights for the afternoon hours.

Thursday through Saturday...

Chances of precipitation for all of SE Colorado will ramp up during
this period in the forecast, along with cooler temperatures. The
pattern will remain unsettled as there will be a deepening
major shortwave trough that is going to be slowly progressing
towards the south and over the region on Thursday, then splits
with an upper level low retrograding back towards the southwest
on Friday. There is a general consensus between the
deterministic models as to what this U/L low will do once it
becomes cut-off somewhere over the Great Basin region, although
there is some deviation between the solutions. The GFS has this
remaining further to the north, and then moving towards
Colorado with a much more extensive mid-level moisture
advection. The Canadian is more similar to what the GFS is
showing, while the ECMWF is a much drier solution with the
position of the U/L low being further to the southwest and only
allowing for mid-level moisture to be more confined to the
higher terrain with the plains remaining mostly dry. There is
still some time to allow models to resolve this feature better
in the upcoming days, and determine if the plains will be either
more wet or more dry for both Friday and Saturday. It will be
overall cooler, with highs running anywhere from 5 to 10 degrees
below the seasonal average for most locations, especially on
Friday. -Stewey

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1139 PM MDT Sun May 5 2024

onight, gusty southwest winds will continue across the TAF sites.
KALS will gusty to around 35 knots, while KPUB and KCOS have surface
winds near or below 20 knots. At KCOS, LLWS will be a concern
through the next few hours, after which things are expected to mix
out more and bring gustier winds towards the surface. By 15Z or so,
all three TAF sites will see winds gusting 30-40 knots, turning more
westerly. Winds will peak in the afternoon at or above 40 knots at
all three sites before beginning to weaken after 00Z towards the end
of the period. Clouds may also lower a bit during late afternoon
tomorrow, but should stay within VFR.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 AM MDT Monday for COZ058-060.
Winter Weather Advisory until 6 AM MDT Monday for COZ066-068.
Red Flag Warning from 10 AM to 10 PM MDT Monday for COZ224-225-
232-233-237.
Fire Weather Watch from Tuesday morning through Tuesday
evening for COZ224-225-232-233-237.
High Wind Warning until noon MDT Monday for COZ072>075-079-080.
High Wind Warning until noon MDT Monday for COZ078-081>083-087-
088.

&&

$$

SHORT TERM...KT
LONG TERM...STEWARD
AVIATION...HODANISH