639
FXUS65 KPUB 182032
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
232 PM MDT Thu Jul 18 2024

.KEY MESSAGES...

- More daily thunderstorms expected with a few strong to severe
  possible through this evening and again on Friday.

- Unseasonably cool and unsettled this weekend into early next week.

- Some drying, especially across southeast Colorado, for the
  middle to end of next week, with temperatures warming back to
  near seasonal levels.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 225 PM MDT Thu Jul 18 2024

Overnight convection has spread higher dew points westward across
southern CO with mid 50 to lower 60 readings across much of the
southeast plains and 40s across the high country. Northerly flow
continues across the area along the eastern periphery of the upper
high with weak perturbations within the flow.  Overall forcing looks
a little less than yesterday which appears to limit thunderstorm
coverage a bit, especially across the plains into the overnight
hours. Thunderstorms will continue into the evening hours, drifting
off into the adjacent plains according to HREF members as
thunderstorms and outflows spread off the mountains and encounter
higher CAPE and increasing shear.  The Marginal Risk for severe
thunderstorms still looks on target with high res models suggesting
El Paso county area may have the greatest coverage again today. HREF
mean CAPE is higher than yesterday with values approaching 1500-1750
near the eastern border, so storm strengths should increase as
storms move eastward into more favorable CAPE and better shear
regimes. Hail up to ping pong balls and outflow winds up to 65 mph
will be possible through the evening.

Friday`s pattern looks similar to today though with better forcing
as a shortwave decends the eastern periphery of the upper high
through the afternoon and evening. Recycled monsoon moisture within
the upper high across CO doesn`t really change all that much though
values do come down a bit in the afternoon along the I-25 corridor
and adjacent plains as low level moisture mixes out. Afternoon CAPE
decreases with HREF knocking back mean CAPE values to 500-1000 J/kg
with highest values near the eastern border.  Storms initiate over
the mountains again and develop along a frontal boundary which will
drop southward into northern portions of the southeast plains in the
late afternoon and evening.  With soundings showing more inverted V
profiles on Friday, gusty outflow winds up to 60 mph and locally
heavy rain will be the primary storm risks, however some severe
criteria hail will be possible farther east across northeast
portions of the plains where CAPE and shear are a little stronger
and a convective cluster develops and spreads southward through the
evening along the frontal boundary.

Temperatures will be a little warmer on Friday, but still at or
below climo for most areas. -KT

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 225 PM MDT Thu Jul 18 2024

Latest ensemble and operational model data supports another cool and
fairly unsettled pattern developing across the region through the
weekend, as upper level ridging remains progged to elongate north
and west across the Great Basin and Intermountain West, leading to
unseasonably cool north to northwest flow aloft in place across the
Rockies. While available moisture does thin out within the northerly
flow aloft, there will continue to be bouts of increased uvv and
moisture, especially across Eastern Colorado, with passing waves
translating down the backside of the upper ridge across the Northern
Rockies and into the High Plains. These waves will bring cold fronts
and surges in available moisture, with continued daily chances of
showers and thunderstorms, especially over and near the higher
terrain, throughout the weekend and into early next week. The
strongest cold front on Saturday night could keep showers and
storms ongoing across the region into Sunday morning, with Sunday
looking to one of the coolest days of the next week with highs well
below late July levels in the 70s to lower 80s across the Plains.

The upper high again looks to slowly slide south and east by the
middle of next week and could be sliding into western Colorado by
the end of next week. This will shift upper level flow to east
to northeast across Eastern Colorado, with weak southerly flow
developing across Western Colorado. Main signal is slowly warming
conditions across the region and back to seasonal levels by the end
of next week. A drier and more subsident airmass will move across
Eastern Colorado, while Western Colorado will see a slow increase
in available moisture once again, keeping the best chances of daily
storms along and west of the ContDvd for the end of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1124 AM MDT Thu Jul 18 2024

Another round of thunderstorms will develop over the mountains
and spread into the adjacent lower elevations this afternoon
through early evening. Winds will be dominated by southeast to
easterly winds for KCOS and KPUB before -TSRA will contribute to
erratic wind directions and gusts up to around 40 kts after 21z
as thunderstorms move off the mountains. Probability of
thunderstorms directly impacting the terminals is under 50%
right now so will maintain VCTS in both KCOS and KPUB tafs but
outflow winds are more likely affect both terminals so have
included a tempo group for this probability. KALS will also see
VCTS and -SHRA this afternoon with erratic gusty outflow winds
up to 40 kts possible. Thunderstorms should move east of the
terminals by 01-02z with clearing skies overnight. Another round
of thunderstorms will be possible Friday afternoon. -KT

&&

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

&&

$$

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