806
FXUS65 KPUB 211736
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1136 AM MDT Fri Jun 21 2024

.KEY MESSAGES...

- A Flash Flood Watch is in effect from Noon until Midnight tonight
  for the San Juan Mountains.

- Thunderstorms increase in coverage and severity across the high
  country today, with main risks being flash flooding, damaging winds
  gusting to 60 mph, large hail to 1 inch diameter, and lightning.

- Warming and drying trend into early next week, most notably
  across the southeast Plains, with temperatures some 10-15F above
  seasonal levels early next week.

- An uptick in daily showers and storms for the middle and end of
  the next work week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 343 AM MDT Fri Jun 21 2024

Currently..

A surface low is in place over Pueblo County, bringing gusty
southwesterly winds to the southern I-25 corridor and our
southwestern plains, and gusty southerlies to our far eastern
plains. Trinidad recorded southwesterly winds gusting to 35mph at
130am and Lamar recorded southerly winds gusting to 30mph around the
same timeframe. Temperatures are warm this morning, with most
locations still in the mid to upper 60s across the I-25 corridor,
and even some low 70s on the eastern plains as of 2am. Dewpoints are
in the 50s and low 60s on the plains. Satellite and radar imagery
show continued rain showers over the high country, where many
locations have seen significant moisture over the past 24 hours.
MRMS 3 hour precip totals are estimating portions of the San Juans
at around 0.65 inches of rain between midnight and 3am this morning.
With more rain and storm chances in store for today, our warm and
moist airmass and previous rainfall will increase chances for
excessive rainfall across the high country this afternoon and into
this evening.

Today..

Models bring a messy and weakening trough across Colorado throughout
the day today. This feature will help to usher in even more
moisture, and enough instability to increase our chances of seeing
some strong to severe thunderstorms across the high country today.
With both EPS and GEFS ensemble members showing PWATs in the 200-
220% of normal range over the high country today, along with steep
lapse rates, our main risk with storms this afternoon and this
evening will be excessive rainfall and flash flooding, especially
for our burn scars and flood prone areas. Many of these areas saw
rain yesterday and the day before as well, and will already be
saturated before today`s storms begin to fire up over the area. The
WPC has our San Juans and La Garitas outlooked for a slight risk for
excessive rainfall, with the rest of our mountains in a marginal
risk as well. The San Juans saw the most rain overnight, and have
the highest forecast QPF amounts for today as well. Early in the
afternoon, models paint enough instability over this area to
indicate the potential for very heavy rainfall that could lead to
flash flooding. For this reason, a Flash Flood Watch was issued for
this afternoon, valid from Noon until midnight tonight. With decent
shear and CAPE values of around 1200-1700 J/Kg over the high country
and our mountain adjacent plains, large hail up to 1 inch diameter
and damaging winds with gusts up to 60 mph can`t be ruled out with
any stronger storms that develop as well. The SPC has the San Juans,
the La Garitas, and Lake and Chaffee counties outlooked for a
marginal risk for severe thunderstorms today, but one other area to
watch closely will be Fremont and Teller counties, where higher
shear and instability seem to overlap around max heating this
afternoon. Other than our increased storm chances over and near the
mountains, temperatures today will be around 3 to 6 degrees warmer
than yesterday for most locations, with increasing cloud cover and
breezy southwesterly winds.

Tonight..

High res model guidance suggests that storms begin to die off
quickly after sunset over the Pikes Peak region and the central
mountains, but are likely to continue through the evening hours
further south. Our far southeast mountains look to clear out latest,
with all locations clear by around midnight tonight. With all the
lingering moisture and overcast skies, overnight low temperatures
look to stay in the mid to upper 60s for our plains as we head into
Saturday morning, with 50s for mountain valleys and 40s for higher
terrain locations.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 343 AM MDT Fri Jun 21 2024

Latest model data continues to indicate a warming and drying trend
for the weekend, as drier air within modest west to northwest flow
filters into the region. Ensemble data indicates pwats decreasing
to at and below seasonal levels, most notably across southeast
Colorado, with enough residual moisture across western and into
south central Colorado, to support isolated to scattered afternoon
showers and storms over and near the higher terrain through the
weekend. Sounding data supports convection to be higher based with
the main threats through the weekend being lightning and gusty
outflow winds. With warming aloft and less expected convection, highs
through the weekend will be above seasonal levels in upper 80s to upper
90s across the southeast Plains, and mainly in the 70s and 80s across
the higher terrain, save for 50s and 60s at the peaks.

Warming continues into early next week as upper level ridging builds
across the Southern Rockies and into the Four Corners region by midweek.
This will keep modest and fairly dry west to northwest flow aloft in
place with temperatures areawide continuing to sizzle, especially across
the plains with highs above the century mark and some 10 to 15 degrees
above seasonal levels, with the potential for heat advisories across
portions of southeast Colorado Monday and Tuesday.

The upper high gets pushed south and east through the end of the next
work week, leading to another influx of subtropical moisture within
modest southwest flow aloft across the Central Rockies.  This increase
in available moisture, along with a surge of cooler air and low level
moisture across the southeast plains from a passing High Plains front,
will lead to increased coverage and intensity of diurnal convection
areawide into the end of the next work week. The increased moisture
and expected convection will also lead to slightly cooler
temperatures into later next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1127 AM MDT Fri Jun 21 2024

Thunderstorms will develop over the mountains and move off into
the lower elevations affecting the TAF sites after 22-23z. KALS
will have the best chance for TSRA which could drop cigs into
the MVFR to even high end IFR category with +RA if storms
directly impact the terminal. Gusty outflow winds up to 50 kts
and hail up to 1 inch will be possible across the San Luis
Valley with the isolated stronger storms. Storms will become
less energetic as the move into the I-25 corridor with KCOS
having the greater likelihood for VCTS in the 23z-01z time
period. Gusty erratic winds up to 40 kts will be possible. KPUB
will have a lower chance so TAF will carry VCSH with a wind
shift from the west due to convective outflows around 00z. Winds
and convective cloud cover will diminish after 03z for KCOS and
KPUB, but -SHRA could continue at KALS until 08z. There is the
chance some fog could develop at KALS overnight if skies clear
out quickly enough but some VFR cloudiness is more likely to
prevent this from occuring. -KT

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Flood Watch through this evening for COZ068.

&&

$$

SHORT TERM...EHR
LONG TERM...MW
AVIATION...KT