460
FXUS65 KBOU 232015
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
215 PM MDT Sun Jun 23 2024

.KEY MESSAGES...

- Above normal temperatures expected through next week with mid 90s
  to low 100 readings across the plains and eastern I-25 corridor
  early next week.

- Heat Advisory Monday and Tuesday for the Denver Metro.

- Continued heat across the region through the end of the upcoming
  work week.

- Slight pattern change moving into the weekend bringing a slight
  cool-down and better shower/storm coverage.

&&

.SHORT TERM /Through Monday/...
Issued at 143 PM MDT Sun Jun 23 2024

It`s hot outside.

A quick glance at observed temperatures so far today shows most
locations in the plains have already made it to the mid 90s. The
warmest spots in our CWA look to be Logan county (99s from
AWOS/RAWS/CoAgMet stations) and Phillips county (100F at the Haxtun
CoAgMet). Across the I-25 corridor, there`s been a few upper 90s
readings... with maybe a degree or two to go at most locations.
Meanwhile, radar has been quiet so far today and only a couple of
high-based are expected later this afternoon given meager
instability.

Overnight lows tonight should remain above normal across the
forecast area, with low generally in the upper 50s to mid 60s for
the plains. Guidance shows a strong signal for weak downslope flow
to continue overnight for the western metro, with HREF mean MinT
close to 70F in some spots.

Another hot day is expected on Monday, with temperatures quickly
rising into the 90s during the mid/late morning hours. Forecast
highs are pretty similar to today with relatively similar mid-
level temperatures expected. Main change in this period was to add
the western suburbs zone (COZ039) into the Heat Advisory.
Temperatures are marginal but the limited relief overnight tonight
and the warm start to the morning was just enough to tip the
scales towards issuing, though it was admittedly a marginal/50-50
decision.

One caveat for tomorrow`s temperatures is the coverage of showers
in the afternoon hours. Guidance shows a slight increase in
moisture/instability tomorrow afternoon, and isolated to widely
scattered showers should develop near peak heating. Gusty outflow
winds will be the main threat (DCAPE > 1500 J/kg) and would also
bring some relief from the heat.

&&

.LONG TERM /Monday night through Sunday/...
Issued at 143 PM MDT Sun Jun 23 2024

Tuesday...This is shaping up to be another very hot day region wide.
Several pieces of ensemble guidance are showing 90-99% chances of
exceeding 95F across the Denver Metro and points east which would
make it 7 days this month of 95+F heat which we have only
accomplished two other times through June 25th since 2000. The one
fly in the ointment, because flies love ointment I guess, is the
higher based convection and quicker moving outflows and cirrus
shield that could keep us cooler than currently expected. With
700hpa temperatures projected to exceed 19-20C it`s downright hot
regardless of the time of the year, even in the high terrain where
mid to upper-60s above 10kft are possible.

Wednesday - Saturday...A bit more moisture tries to work into the
region from the southwest aloft as mid-level ridging starts to
meander back towards the west and we tap into some Gulf of Mexico
moisture across the east along the surface. West-northwest driven
shortwave troughs carve into the top of this ridge throughout the
week as well allowing heights to decrease, meaning some cooling
within the column, and some weak lift for diurnally driven showers
and thunderstorms. We`re still thinking several more days with 90+F
heat though timing of showers/storms and cloud cover could keep
us cooler the later part of this work week. It`s really not until
we get into Friday and the first half of the weekend do we start
to see better chances for sub-90F heat along with more scattered
showers and storms. The reprieve could be short lived with ridging
reloading just south of the region bumping temperatures backup
again.

&&

.AVIATION /18Z TAFS through 18Z Monday/...
Issued at 1131 AM MDT Sun Jun 23 2024

VFR through the TAF period. Winds are expected to remain light and
variable this afternoon. Still a very slight chance of a stray
outflow boundary this afternoon, with a better chance by BJC.
Typical drainage flow is likely overnight tonight. There is a
better chance for outflow from high-based showers on Monday
afternoon.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM to 9 PM MDT Monday for COZ039.

Heat Advisory from 11 AM Monday to 9 PM MDT Tuesday for COZ040.

&&

$$

SHORT TERM...Hiris
LONG TERM...Heavener
AVIATION...Hiris