093
FXUS65 KPUB 231143
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
543 AM MDT Thu May 23 2024

.KEY MESSAGES...

- Critical Fire Wx conditions across lower eastern slopes of
  southern mtns today.

- Meteorological conditions for critical fire behavior will
  occur this afternoon across most of the plains, San Luis
  Valley and lower Fremont County, but fuels are not critical
  these areas.

- Hot and Windy most of plains today.

- Patchy frost will occur over areas of El Paso County tonight
  through Friday morning.

- Critical fire weather again across lower eastern slopes of
  southern mtns tomorrow, but more widespread on Saturday.

- Isolated afternoon and early evening thunderstorms will be
  possible over the higher terrain on Friday, and a stray storm
  or two is possible over the plains north of Highway 50.

- Scattered showers and thunderstorms will become more likely
  this weekend, with better chances for the plains.

- Only a few thunderstorms will be possible during the afternoon
  hours over the higher terrain on Monday, then thunderstorm
  activity will have an uptick from Tuesday through Wednesday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 330 AM MDT Thu May 23 2024

Currently...

Besides all the biological echoes on radar at 2 AM (Miller Moths
pushing westward, skies clear across the region this morning. Temps
this morning were still rather mild over the far eastern plains,
with readings in the 60s, while 40s were noted over El Paso county.
The valleys ranges from the 30s to around 50F. Mtns were in the 30s
and 40s. Dewpts were quite low in the mtns with readings in the
teens. An impressive LLJ was noted, with Lamar gusting from the
south to around 40 mph.

Today...

In a nutshell, sunny, windy and hot most areas. Temperatures will be
running several degrees above normal all areas. This is due to a
short wave moving in from the west causing a lee trough to develop
over the plains which in turn is going to cause gusty SW sfc winds
downsloping off the higher terrain. Correspondingly, temps will
rise into the 80s to L90s across the plains today, with minimum
humidity values in the single digits to L10s.

In the mtns it will be quite breezy/windy, with gusts in the higher
terrain in the 45 to 55 mph range. The SLV will see gust to 40 mph
range and the I-25 corridor region in the 25 to 35 mph range.

This same short wave will bring a chance of some high level thunder
snow showers to the central mtns later this afternoon and especially
this early evening, mainly areas north of Cottonwood Pass.

Tonight...

A cool front will push down the plains this evening, with winds
shifting to the north by late evening into the nighttime hours. It
will remain dry with the frontal passage with somewhat cooler air
advecting into the region. Temps in N El Paso county will drop
into the 33-35F range and some patchy frost will be possible.
After coord with NWS BOU, will hold off on any frost hilites for
now. /Hodanish

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 330 AM MDT Thu May 23 2024

Friday...

A frontal boundary associated with the passing wave on Thursday will
allow for some colder air advection behind it on from the north and
because of this there will be some patchy areas of frost during the
morning hours over El Paso County.

As the U/L low continues to propagate eastward and further away from
the region, this will allow for the pressure gradient to loosen and
therefore winds will not be as strong. In addition, upsloping winds
will help to mitigate the threat for the drier southwesterly winds
in the Trinidad area, and because of this I am becoming less
confident that there will be widespread critical conditions with
only some confined areas closer to the Sangres with overall more
"spotty" conditions, and therefore I`ve decided to keep the
highlight as a Fire Weather Watch for Zone 225 tomorrow. It will
remain mostly dry for most of SE Colorado, with the only exception
being over the higher terrain and especially north of Highway 50
again, where the best residual mid-level moisture will be. A weak
cold frontal boundary associated with the exiting U/L low will move
through early in the morning and switch winds to a northerly
direction which will help to advect in cooler temperatures and
therefore highs, especially for the plains, will be notably cooler
by some 10 to 15 degrees.

Saturday through Sunday...

Latest models still reflect that this period of the forecast will
begin to become more active as a major shortwave trough over well
upstream begins to slowly make its way towards the region and allows
for an increase of moisture and instability. Afternoon and evening
showers and thunderstorms will be more widely scattered over the
higher terrain, with some high elevation snow likely increasing and
additional accumulations likely, especially across the central
mountains. As indicated with increasing PWAT values, chances of
showers and thunderstorms will also increase over the plains,
especially for locations north of Highway 50. There will still also
be some high elevation snow, although it will likely be confined to
highest of elevations for the northern Sawatch and Mosquito Range,
and only a couple of inches at best.

As the U/L low associated with this major shortwave progresses
southeastward, it will further increase chances of precipitation
across the region, although there continues to be some deviation
with the deterministic models about the timing and progression of
this. The ECMWF still has the progression being much quicker and
therefore drying out sooner, and this aligns more with what the
Canadian model is displaying. The GFS has made the least amount of
change within past runs and is proving to be more reliable with
resolving this feature with better continuity, with the U/L low
passing just to the north midday on Sunday, resulting in more
convection, and this more closely aligns with what the NAM12 shows.
Both the ECMWF and Canadian, with the speed and progression much
quicker than the other two, has most of the convection clearing out
by Sunday with only some isolated thunderstorms developing during
the afternoon over the higher terrain. Given the higher PWAT values,
there will be a low risk of flash flooding with some of these
storms, especially if they become stationary or train over a burn
scar area and/or urbanized area prone to flooding. There could be
some critical fire weather conditions for the eastern slopes of the
southern mountains again on Sunday.

Monday through Wednesday...

A cold front will move through with the major shortwave on Sunday,
which will result in cooler temperatures for highs on Monday. With
high pressure building back in behind it and a ridge strengthening
upstream, there will be mostly dry conditions, with only a few
isolated afternoon storms over the higher terrain. The ridge moving
over on Tuesday will cause temperatures to rebound quickly, yet
there will also be an advection of mid-level moisture with the upper
level disturbance upstream which will cause an increase in
thunderstorm activity over the higher terrain on Tuesday afternoon
and then spread into the plains later in the evening. There will
also continue to be an uptick in even more thunderstorm activity as
deterministic models show another approaching major shortwave trough
towards the end of next week.    -Stewey

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 537 AM MDT Thu May 23 2024

VFR conditions are anticipated during the next 24 hours at all 3
taf sites, KPUB, KALS and KCOS.

As for winds, a prefrontal trough and cold front will move
across KCOS and KPUB during the evneing time period. Winds will
become gusty from the S-SW later this morning, becoming more
west to northwest late this afternoon, then shifting to
northerly later this evening. Winds will be gusty this afternoon
and during frontal passage.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 10 AM this morning to 9 PM MDT this
evening for COZ225.
Fire Weather Watch from Friday afternoon through Friday
evening for COZ225.
Fire Weather Watch from Saturday morning through Saturday
evening for COZ225.

&&

$$

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