333
FXUS65 KPUB 281729
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1129 AM MDT Tue May 28 2024

.KEY MESSAGES...

- Strong to severe storms are possible (40-60% chance) for
  today, especially for our southeastern plains.

- Daily thunderstorm chances (40-60% chance) will continue
  across the southeast mountains/plains through the week, with
  strong to severe storms possible along and east of I-25.

- Slow drying and warming trend starts late weekend into early
  next week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 322 AM MDT Tue May 28 2024

Currently..

Satellite imagery depicts troughing over the northeastern and
northwestern conus, with broad ridging overhead. Temperatures are
still in the 40s and 50s across the plains as of 3am this morning,
with dew points in the 30s and 40s. Other than a bit of lingering
mid-level cloud cover on our far eastern plains, sky conditions are
mostly clear. Light northerly winds are in place over the I-25
corridor.

Today and Tonight..

High res models bring a bout of shortwave energy and easterly
surface winds through the area this afternoon, which will help to
bring in additional moisture and instability. Our mountains will see
weak general thunderstorms develop by around noon, with main risks
for the high country today being gusty winds and lighting. Forecast
soundings across our far eastern and southern plains however, show
anywhere from 2500 to 3000 J/kg of CAPE this afternoon, especially
for eastern Las Animas and Baca counties. These areas are also
looking at 35 to 45kt of 0 to 6km bulk shear, and are outlooked as
Slight Risk for damaging winds and hail for this afternoon as well.
CAMs show the potential for to severe storms over Kiowa, Bent, and
Prowers counties also, and the SPC has included much of the plains
in their marginal outlook, though it does look like the western
extent of moisture and instability will be limited at least somewhat
this afternoon. Most high res model guidance develops storms over
the southern plains by around 1pm this afternoon. These storms look
to become strong to severe as they push through eastern Las Animas
and Baca county after 3pm this afternoon, where main threats will be
large hail up to 2 inches and winds gusting to 60 mph. Another round
of storms looks to develop over the Pikes Peak region after 2pm.
Chances for storms becoming severe over El Paso and Pueblo County
today are low due less instability and less moisture further west
this afternoon, but as storms push eastward into Kiowa, Bent, and
Prowers counties, some storms may become strong to severe later this
afternoon and this evening, with main threats being large hail up to
2 inches and 60 mph winds. Daytime highs today will be near to just
slightly above normal, with most of our plains warming into the mid
80s, 70s for mountain valleys and El Paso County, and 50s and 60s
for higher terrain locations. Storms look to weaken and push into
Kansas by around 10 or 11pm at the latest this evening, with mild
temperatures and continued moist southeasterly flow persisting
through the overnight hours into Wednesday morning. Continued
southeasterly winds and potential moist outflows will help to set
the stage for potentially more available moisture and a possible
higher risk for strong to severe storms on Wednesday.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 322 AM MDT Tue May 28 2024

Low amplitude upper ridge will slide east into the plains on
Wed, as moderate w-sw flow aloft continues. At the surface,
expect Tue evening/overnight convection to our southeast to send
some sort of outflow westward across the plains, potentially
pushing deeper low level moisture all the way west to I-25 by
Wed morning. It may then take much of the day for instability to
build over the plains given rather cool/stable air mass
initially in place, but by late afternoon/early evening, most
models show CAPE of 1000-2000 J/KG over the plains east of
I-25. Model scenarios point to late (around 00z) convection
firing near the Palmer Divide and Raton Mesa, with strong storms
then pushing eastward toward the KS border in the evening. Main
negative factors for Wed convection include lack of a strong
s/w trigger (best upper energy ejects fairly far to the north)
and rather weak 0-6km shear values (around 30 kts) due to
pronounced weakness in the wind field from the surface through
about 3km AGL. SWODY2 has most of the plains in a marginal
severe risk, with the southern end of the slight into Kiowa
County, which looks reasonable as stronger forcing is to the
north. Farther west over the mountains and interior valleys,
surface air mass is rather dry, with any convection likely
staying high based and weak.

Thursday is setting up to potentially be a rather active convective
day across the plains, though numerous hard to time mesoscale
details will play a major role in storm formation/evolution.
Fairly strong upper wave will move through the state in the
afternoon, providing enhanced upward motion to all of srn
Colorado in the afternoon/evening. Surface pattern is rather
messy on the plains early in the day, with outflow enhanced
cold front (and accompanying north winds) dropping south through
the plains in the morning, following by increasing easterly
surface winds and westward moisture advection in the afternoon
as surface low pressure spins up over nern NM. Progged CAPE over
the plains approaches 3000 J/KG over the far east, with values
in the 1000-2000 J/KG range all the way west to I-25. Again,
0-6km shear isn`t particularly strong (30-35 kts), but if
forecast deep instability develops, shear/instability combo will
likely be sufficient for widespread severe storms, potentially
all the way back to the I-25 corridor. Set-up again looks like
convection forms over the higher terrain mid-afternoon, then
strengthens late afternoon/evening as it encounters deeper
instability on the plains. Main negative factor for storms would
be if post-frontal air mass ends up cooler/more stable than
currently forecast due to potential large cold pool from Wed
night convection to our north, but tough to forecast that at
this time range (48+ hours out). SWODY3 reflects the increased
chance of severe storms Thu, with slight risk covering almost
all of the plains from I-25 eastward. Would lean toward
strong/damaging winds being the greatest risk Thu, though CAPE
may be large enough to overcome weak shear and thus storms could
produce large hail as well. Mountains and interior valleys may
see an uptick in convective coverage Thu afternoon/evening with
better forcing, but low level moisture remains lacking, so
widespread wetting rains look unlikely.

Thunderstorm pattern remains in place Fri on the plains, with
moderate wly flow aloft and residual low level moisture
lingering, though convective outflows from Thu night convection
will play a major role in the evolution of the surface air mass
and resultant instability. Forecast at this point has scattered
pops for much of the area, which looks fine for now. Trend
toward drier weather then develops over the weekend into early
next week, as upper flow turns slightly more swly and increases
by Sunday, drawing some drier air into the region, especially
Sun/Mon.

Temps for the Wed-Fri period will end up roughly near to
slightly above seasonal averages, before warmer weather arrives
over the weekend into early next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 1029 AM MDT Tue May 28 2024

Showers and thunderstorms developing over the mountains will
drift off into the adjacent lower elevations during the late
afternoon and evening. VCSH/VCTS will be possible at all three
terminals, though coverage looks too isolated to put into the
TAFs just yet, though will time some gusty outflow winds into
all three terminals in the afternoon. If VCTS does impact the
terminals, then localized erratic gusts to 40 kts will be
possible. Moisture will increase with easterly winds overnight
at KCOS and KPUB. Have delayed the onset of stratus at KCOS
until 10z, as recent models have backed off on this scenario
some. Have kept conditions MVFR for now, but it is possible that
a stronger moisture surge originating from yet to form
thunderstorms to the east could result in a few hours of IFR
conditions at KCOS during the early morning hours. -KT

&&

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

&&

$$

SHORT TERM...EHR
LONG TERM...PETERSEN
AVIATION...KT