609
FXUS65 KPUB 261751
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1151 AM MDT Wed Jun 26 2024

.KEY MESSAGES...

- 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.

&&

.UPDATE...
Issued at 1022 AM MDT Wed Jun 26 2024

Increased PoPs over the southeastern plains due to early
convective initiation. -Stewey

&&

.SHORT TERM /THROUGH TONIGHT/...
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

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
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.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1150 AM MDT Wed Jun 26 2024

VFR conditions are expected to prevail for all TAF sites (KALS,
KCOS, and KPUB) throughout the forecast period. Winds will be
increasing and becoming more synoptically influenced throughout the
day, but become more diurnally influenced by later in the forecast
period as they decouple and weaken. Winds are expected to be gusty
at times out of the ESE-SSE at both KCOS and KPUB during the
afternoon. SHRA and TSRA are expected to be in and around the
vicinity of all stations later in the afternoon and though the
evening today, mainly after 22Z at KALS and 00Z at KCOS and KPUB. If
SHRA/TSRA does develop, it could temporarily reduce CIGs and VIS to
MVFR/IFR criteria. It could also result in periodic windshifts and
increased wind speeds for all terminals. -Stewey

&&

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

&&

$$

UPDATE...
SHORT TERM...KT
LONG TERM...SIMCOE
AVIATION...STEWARD