268
FXUS65 KBOU 030014
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
614 PM MDT Sun Jun 2 2024

.KEY MESSAGES...

- Summer heat through most of this week, with a few 90 degree
  readings over the plains. Breezy but a little cooler Tuesday.

- Chance of showers and storms for Monday night

- Return to more normal temperatures and a chance of storms
  towards next weekend

&&

.SHORT TERM /Through Monday/...
Issued at 231 PM MDT Sun Jun 2 2024

Lift from the wave tracking across the region is producing strong
to severe thunderstorms over southern Wyoming and western
Nebraska. Additional thunderstorms extend west-southwest into
north central Colorado. As these storms progress eastward, they
will encounter a more moist and unstable airmass. MLCAPE has
climbed to 1000-2000J/kg over the northeast plains and as storms
move into and/or form over the area, they should become severe
with large hail (tennis ball size) and damaging winds. Easterly
winds are prevailing across much of northeast Colorado and are
helping to retain low level moisture. Earlier model runs showed
dry gusty west winds for most of the area and not these northeast
winds, thus forecast confidence is on the low side and expect
convection a little more south. The 18Z NAM shows 400-800 J/kg
with upper 30s dew points, so we could see some stronger storms as
far south of I-70. By mid to late evening, expect the storms to
progress east of the area with dry conditions then in place for
the night.

For Monday, weak ridging in the westerly flow will prevail. It
will be a warm day with highs climbing into the mid to upper 80s
across northeast Colorado. With dew points in the 30s and CAPE
less than 300 J/kg, expect dry conditions, though there should be
high-based cumulus clouds with virga and perhaps dry microbursts.
Better chance for showers and storms will come Monday night as a
short wave trough tracks across the region.

&&

.LONG TERM /Monday night through Sunday/...
Issued at 245 PM MDT Sun Jun 2 2024

Models have a weak upper trough move across the CWA Monday night
into Tuesday morning. This feature looks a bit stronger than it
did yesterday. The QG fields show weak upward vertical velocity
for the CWA Monday night, then weak downward motion Tuesday.
There is neutral energy progged Tuesday night through Wednesday
night. The low level pressure and wind fields show downsloping
surface winds to dominate both Tuesday and Wednesday, with
drainage patterns during the nights.

For moisture, precipitable water values are in the 0.50 to 1.10
inch range over the CWA Monday night. CAPE is just fair Monday
evening, and mainly just over the eastern half of the plains. The
northern half of the CWA will have the highest pops, with 30-50%s
in the mountains and 30-40%s over the northeast corner. For
Tuesday through Wednesday night, moisture dries out and there is
no CAPE progged. Will keep those periods dry. Of note, cross
sections show a bit of a mountain wave set-up later Monday night
into Tuesday after the upper trough passes, so I will make sure
to beef-up the downsloping winds a bit along and east of the
divide in the mountains and foothills.

For temperatures, Tuesday`s highs are a tad cooler than Monday`s,
but Wedensday`s highs are 1-4 C warmer. So "now" it looks like
the first Denver 90 degree F reading will be on Wednesday?

For that later days, Thursday through Sunday, models have upper
ridging in control of Thursday`s weather.  By Friday, continuing
through the weekend, the upper ridge gets pushed a bit west, at
least enough to allow for cooler air to get into the CWA.
Precipitable water values and surface dew points are pretty high.
Instability is decent too.  Scattered pops seem reasonable; perhaps
even higher, but that is still quite a few days away. Temperatures
could cool to below seasonal normals for highs on Saturday and
Sunday.

&&

.AVIATION /00Z TAFS through 00Z Tuesday/...
Issued at 614 PM MDT Sun Jun 2 2024

VFR conditions through Monday.  There is a huge line of storms
exiting Colorado to the east. At the terminals, convective
potential is essentially 0 for the remainder of the evening. Weak
showers along the Wyoming border continue to generate strong
north winds to the north of the terminals. Another gust front from
the north is not out of the question, but if one occurs it would
just prolong the north winds this evening. From now until about
02Z, north winds should weaken, gusting 25-30 kts now, down to
10-20 kt by 02Z. By 06-08Z, drainage winds out of the SSW should
go 8-12 kts all night long, becoming WSW after 14Z. Wind direction
might be a challenge from midday to the afternoon hours, as some
guidance has WNW winds, others an east wind. Either way, winds
will be under 10 kts until virga showers form after 20Z. Then
gusty winds to 25 kt from any direction are possible. For now, we
will handle the potential from gusty winds from weak convection
with a tempo group. Rain is not expected to reach the ground at
near any of the terminals Monday afternoon.

&&

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

&&

$$

SHORT TERM...Meier
LONG TERM....RJK
AVIATION...Schlatter