622
FXUS65 KPUB 082137
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
337 PM MDT Sat Jun 8 2024

.KEY MESSAGES...

- Severe thunderstorms, with all hazards, expected through this
  evening across the eastern plains, mainly along and north of
  Highway 50.

- Thunderstorms, a few strong to severe, possible Sunday and
  Monday across the mountains and adjacent plains with risks
  transitioning towards hail and heavy rainfall capable of
  producing localized flash flooding.

- Heat build backs into the area by the middle part of next
  week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 334 PM MDT Sat Jun 8 2024

Severe risk continues this afternoon across the plains, with latest
radar imagery showing more isolated thunderstorm development across
the Pikes Peak region along the Raton Mesa. In these areas have seen
lee troughing occur while a well defined shortwave moved overhead.
Latest RAP analysis showing some CIN remaining in place, which has
likely limited any robust updrafts at this. However, guidance now in
fair agreement with any remaining CIN eroding here in the near term,
with intensity of the current storms likely increasing. While can`t
completely rule out a strong to severe storm over the far southern
area near the Colorado and New Mexico border this afternoon, think
they will be less likely there given some drier air, lower
instability, as well as lower shear. From Pueblo up towards the
Springs, will see more robust updrafts over the next couple of
hours, given a steady southeast wind advecting low 50s dewpoints
into this area, resultant CAPE values around 1000 j/kg, and shear
upwards of 35 to 45 kt. In these areas this afternoon, expect hail
up to around 1.5 inches and wind gusts up to 60 mph. Think this risk
will continue through around the 5 pm time frame, with development
likely shift to the east.

By early this evening, will see the isolated to widely scattered
severe storm development to shift east into the plains. Once again,
given the above mentioned moisture, instability, and wind shear
values, think the highest risk of severe storms will be along and
north of the Highway 50 corridor. Will closely monitor the severe
threat for Baca county though, as observational data showing some
higher dewpoints inching into this area. Along and north of Highway
50 and especially near the Colorado and Kansas border, low to mid
60s dewpoints and steep lapse rates are yielding CAPE just above
3000 j/kg. This much higher instability and moisture along with
increasing shear will not only support the continued severe risk,
but will support the risk for higher end wind gusts and larger hail.
This is especially as CAMS are indicating more upscale development
into linear segments. So, will continue to message a high chance for
winds up to 80 mph and large hail up to around 2 inches for areas
northeast of a Las Animas to Springfield line. The risk for a few
tornadoes also remains for these areas even if linear convection
develops. Should see the severe risk quickly lower by around the 7
pm time frame but as instability remains in place, can`t rule out
additional thunderstorm development into the late evening time
frame. While a low confidence scenario at this time, its possible
the instability axis swings back into the I-25 corridor and
southeast mountains. If this were to occur, could see at least
isolated development in these locations.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 334 PM MDT Sat Jun 8 2024

By Sunday, will see rising heights and weakening flow, but will see
moisture and instability remain in place. It does look as if the
moisture/instability axis shifts further west, with increased
chances for showers and thunderstorms over the mountains and
mountain valleys. Guidance is in fair agreement with bringing mid to
upper 50s dew points right up to the southeast mountains, and with
CAPE values easily in the 1000-1500 j/kg range and quite possibly
approaching 2000 j/kg.  While there is weakening flow that will
support less organized development on this day, I think the risk for
hail and damaging winds will remain. Overall setup could support the
risk for more wet microbursts/damaging winds on Sunday. The highest
risk for severe storms will likely be across the southeast mountains
into the I-25 corridor. Additionally, still closely monitoring the
potential for heavy rainfall and flash flooding, for these same
areas. With higher moisture content air, forcing/focus right into
these areas, and with slow storm motions, definitely have concerns
for flash flooding. Did debate issuing a Flash Flood Watch for these
areas on Sunday, but have opted not to at this time and will let
later shifts take a look at additional guidance.

The risk for heavy rainfall and flash flooding continues Monday, as
upper energy evolves into a closed low on this day. Guidance begins
to really diverge with this system, most importantly placement of
this system. So, while there might be a slightly higher chance for
precip development to shift more across the Continental Divide on
Monday, think guidance could easily shift back east. So, at this
time, will continue to message more widespread precip development
over much of southern Colorado. Severe risk does lower, but will
remain possible just given the nature of closed upper level lows. It
does appear that by Tuesday, we`ll see coverage of precip chances
lower that continues on Wednesday as upper ridging is the trend.
This will return building heat to the area though, with well above
normal temperatures in the 80s and 90s, and quite possibly 100
degrees, returning to southern Colorado by mid week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 211 PM MDT
Sat Jun 8 2024

Outside of thunderstorm chances, VFR conditions are expected at all
three TAF sites, KCOS, KPUB, and KALS, for the next 12 hours.
Afternoon thunderstorm activity is expected over and near both
KCOS and KPUB from 20Z until around 02Z today, with main
concerns being gusty outflow winds in excess of 40kt, hail, and
lightning. After 10Z tonight, MVFR and IFR ceilings are expected
to develop at KCOS and KPUB, with conditions improving after
16Z tomorrow morning.

&&

.HYDROLOGY...
Issued at 334 PM MDT Sat Jun 8 2024

Rapid snow melt will continue across the mountains leading to
elevated flows along the Arkansas River from Leadville to Canon
City through Monday as well as on smaller creeks and streams in
and near the mountains. Flows are expected to remain within
banks for most locations along the Arkansas River but fast flows
can still be dangerous. Slightly cooler temperatures may
decrease the snow melt Sunday and Monday, however the potential
for heavy rainfall will increase both days for the southeast
mountains and adjacent plains. This could cause localized flash
flooding and push flows above the projected bank full forecast
for localized areas depending on where the rain falls.
Latest projections place the heaviest rainfall across Teller,
western El Paso and Fremont counties on Sunday though the flash
flood risk still looks localized. Continue to monitor weather
forecasts closely.

&&

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

&&

$$

SHORT TERM...RODRIGUEZ
LONG TERM...RODRIGUEZ
AVIATION...EHR
HYDROLOGY...KT/Rodriguez