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807
FXUS65 KPUB 260955
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
355 AM MDT Wed Jun 26 2024

.KEY MESSAGES...

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- Slightly cooler with an uptick in thunderstorms today, with a
  few severe storms possible across the southeast plains this
  afternoon and evening.

- Rain showers and thunderstorms expected each day Thursday
  through Tuesday.

- Some days may have strong to severe storms during the long
  term period, with Thursday and Sunday of biggest concern at
  this time.
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&&

.SHORT TERM /THROUGH TONIGHT/...
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Issued at 353 AM MDT Wed Jun 26 2024

A shortwave across the Great Basin will be cutting down the upper
ridge across CO today bringing an uptick in thunderstorms as forcing
moves across during the late afternoon and evening. Meanwhile a cool
front/outflow boundary will backdoor into the southeast plains,
bringing an increase in surface dew points through the day.  By 21z,
consensus is dew points will increase into the upper 40s to around
50 along the I-25 corridor to around 60 for the far eastern plains.
Precipitable waters increase even across the mountains today as the
southerly tap of subtropical moisture shifts westward with the
incoming shortwave.  Values will range from 0.75 across the
mountains to 1.5 across the plains. This will be approaching 150+%
of normal based on extrapolation of blended TWP satellite products.
So thunderstorms will have greater coverage and precipitation
efficiencies over the mountains today.  And, as storms develop/push
eastward into the southeast plains, they will encounter HREF mean
CAPE values of up to 1250 J/kg of CAPE and deep layer shears of 40
kts which will be sufficient for a few strong to severe
thunderstorms. Soundings still show inverted V structure, especially
closer to the mountains and across the Raton Mesa region/southern
plains so gusty outflow winds over 60 mph looks like the main risk.
CAPE and shear appear better north of highway where a combined hail
risk will be included.

Timing of thunderstorms differ across the plains between the CAMS
models with some showing storm initiation as early as 1 PM along the
Palmer and Raton ridges as convective temperatures are reached.
Another round spreads off the mountains late this afternoon and
evening as forcing from the shortwave gets closer.

A low level jet this evening allows for a thunderstorm cluster to
get organized across our far eastern counties which could keep
convection going until 1 AM near the eastern border.  Will keep
thunderstorms in the forecast well into the overnight hours out
east, though think main severe risk will diminish after 9-10 PM as
focus shifts eastward. Meanwhile, the moisture plume over the
mountains may keep showers and isolated embedded thunderstorms going
into the overnight hours along the Continental Divide a well.

Temperatures today will be a little cooler than yesterday but still
could hit 100 degrees across portions of the southeast plains before
thunderstorm outflows cool things off in the evening.  With residual
cloud cover tonight, overnight lows will stay on the warm side for
all areas. -KT
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&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
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Issued at 353 AM MDT Wed Jun 26 2024

Thursday - Tuesday: Active weather is expected throughout much of
the long term period for south central and southeastern Colorado.
Flow will mostly fluctuate between southwesterly to westerly with
embedded shortwaves pushing over the area, bringing periods of
enhanced forcing. Along with that, moisture will remain in place
through much of this timeframe. With the heightened periods of
forcing and the abundant moisture in place, rain showers and
thunderstorms are anticipated each afternoon across the area,
initially along the mountains during the early afternoon hours and
expanding across the valleys and plains through mid to late
afternoon hours. Along with that, some days may bring strong to
severe storms, with Thursday and Sunday of particular concern at
this moment, with both days having a better combination of shear,
moisture, and instability. Thursday is a rather unique day though,
as rich moisture and modest shear will overspread most of the area,
which will open the possibility of strong to severe storms for the
entirety of south central and southeastern Colorado, though weaker
shear is anticipated to keep the severe risk lower. The most likely
hazards at this time with any strong to severe storms is expected to
be strong to severe wind gusts and large hail. In addition, flooding
could become a concern with any slower moving thunderstorms any of
these days, given the moisture content in place. With all of that
said, showers and storms in place any of these days is expected to
decrease in coverage and intensity throughout the mid to late
evening hours as instability starts to lessen. Looking at
temperatures, the stretch of hot days continue. Much of the region
will remain near to slightly above seasonal values for late June to
early July. With that said though, a cold front will push southward
over the area late Friday into early Saturday, helping to bring at
least one day of minor relief from the heat.
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&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
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Issued at 353 AM MDT Wed Jun 26 2024

There is a better chance for TSRA at all three terminals today and
will carry this in a tempo group at all three TAF sites.  Best
chance will be after 23z.  Winds at KCOS and KPUB will shift from
the east to southeast this afternoon at 10-20 kts before
thunderstorm outflows dominate winds during the late afternoon and
evening.  KALS will see more south to southwesterly winds today
prior to thunderstorm development.  Winds will become light and
variable at KALS overnight but become east to southeasterly at KCOS
and KPUB.  Most areas will stay VFR overnight but will need to
monitor the westward transport of low level moisture into the
mountains as some MVFR to IFR stratus could develop for KCOS and
KPUB with upslope flow if sufficient moisture return occurs. -KT
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&&

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

&&

$$

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