051
FXUS65 KBOU 280912
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
312 AM MDT Fri Jun 28 2024

.KEY MESSAGES...

- Slight risk of severe storms across NE Colorado this afternoon,
  with large hail and strong winds the main hazards.

- Gusty conditions likely at times for almost all areas this
  afternoon.

- Isolated to scattered thunderstorms this weekend, with a few
  strong to severe storms possible Sunday afternoon and evening.

- Drier conditions possible by mid next week.

&&

.SHORT TERM /Through tonight/...
Issued at 140 AM MDT Fri Jun 28 2024

Relatively quiet early this morning now that most of the
precipitation has dissipated or moved east of us. Locally breezy
conditions still exist extending across the northern half of our
forecast area, and are keeping nocturnal temperatures quite
elevated - still hovering around 80 degrees in Phillips County as
of 2AM! Meanwhile, a secondary wave of moisture is evident in
water vapor imagery across the Western Slope along the leading
edge of the approaching shortwave, with a disorganized cluster of
showers and thunderstorms moving eastward. Although some weakening
is likely as they near our northern mountains, it`s worth
maintaining at least a chance (30%) of showers across our higher
elevations through around or a little past sunrise. A weak front
is also descending into our northern plains currently and will
bring a period of lighter northeasterly winds to much of the
plains this morning. It could knock a couple degrees off our
temperatures today, but compressional warming will kick in later
today and help reduce its effects. We should still climb to near
or slightly above 90F across the I-25 corridor and plains.

Moisture today will be more limited, with peak PWAT values closer
to 0.7-0.8" for the urban corridor and around 1" in the eastern
plains. With enhanced drying downslope winds this afternoon, and
marginal instability, suspect that storms initiating in the high
country early afternoon will struggle to hold together along the
I-25 corridor. Have adjusted PoPs downward slightly to better
reflect this. MLCAPE will be somewhat more favorable from about
Fort Morgan northeastward (anywhere between 300-900 J/Kg), and
robust deep-layer shear in the 35-45 kt range should support a
few stronger to severe storms late afternoon and early evening in
the northeast plains. It`s worth emphasizing that free air winds
will be stronger today and, with continued dry conditions near the
surface and DCAPE values in excess of 1,000 J/Kg, it would be no
surprise to see somewhat of a repeat of yesterday`s strong
convective winds across our lower elevations, which could locally
reach or exceed 50-60 mph. Widespread fire weather concerns are
not expected given humidity levels mostly above 15-20%, but brief
periods of elevated/near critical conditions will be possible
below ~8,000 ft if any particularly strong outflows coincide with
areas of low humidity.

A secondary cold front will then descend into the plains tonight,
ushering in a cooler night and potentially even some low-level
cloud cover east of the Front Range, setting the stage for more
seasonable temperatures on Saturday.

&&

.LONG TERM /Saturday through Thursday/...
Issued at 140 AM MDT Fri Jun 28 2024

As mentioned in the short term AFD, temperatures should be cooler
on Saturday behind the cold front. Afternoon highs will likely
remain in the low to mid 80s across the plains. Deeper moisture
will gradually advect into the region during the day as it wraps
around the southwestern edge of an upper level ridge located over
the southern Great Plains. There should be isolated to scattered
thunderstorm development, mainly across the Front Range/Foothills
during the afternoon hours, with less coverage across the plains
where the airmass is fairly stable.

The cooler weather will be short-lived, as warmer mid-level
temperatures advect back into the region by Sunday. Some question
as to how much cloud cover there will be in the afternoon hours,
but models generally support a return to low/mid 90s. With
moisture lingering across the region, forecast soundings do show a
better convective environment with modest CAPE along with good
deep-layer shear. Still don`t think overall storm coverage will be
too widespread, but a couple of strong to severe storms would be
possible.

Storm chances will continue on Monday and Tuesday afternoon, with
near normal to above normal precipitable water values in place.
Temperatures should remain pretty warm with highs near or above
90F. A gradual drying trend expected for the latter half of the
week, as a strong upper ridge begins to build off the Pacific
coast.

&&

.AVIATION /06Z TAFS through 06Z Saturday/...
Issued at 1133 PM MDT Thu Jun 27 2024

Evening convection continues to wane across the plains of eastern
Colorado and with that, the bulk of the surface boundaries have
moved east of the Denver terminals, with southwesterly drainage
flow filling in in their wake. There`s another wave of high-based
showers moving over the northern Front Range and foothills, with
an associated northwesterly outflow, but suspect these will
continue to weaken and currently leaning towards this boundary
dissipating before reaching the Denver metro. Expect VFR
conditions to prevail for all terminals overnight.

Some models still show a very weak boundary pushing through the
lower elevations and nearing KDEN ~11-12Z. Will retain a shift to
NE flow in the morning for now, but have tapered it back to keep
away from KBJC and KAPA as it may struggle to make it that far
south. These should be shortlived, with winds potentially becoming
rather variable later in the morning, with speeds generally below
10 kts. May see prevailing NW flow at times.

By 18-19Z, expect NW winds to pick up across the area, with a
stronger surge arriving to all terminals closer to 21Z and lasting
through late afternoon. The greater potential for any convection
will be after 21Z. There will be a few hours where gusty outflow
winds will be possible from any direction with storms in the
vicinity of terminals. Convection will dwindle in the evening with
weaker northwest flow favored most of the night. Late in the
period, models show the passage of a more robust front near 06-07Z
Sat, brining a period of enhanced northerly winds to all
terminals, along with potential for SCT low clouds at/below 020.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...Rodriguez
LONG TERM...Hiris
AVIATION...Rodriguez