366
FXUS65 KBOU 222111
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
311 PM MDT Sat Jun 22 2024

.KEY MESSAGES...

- Upper ridging to move in bringing hotter and drier conditions to
  the forecast area this weekend into early next week.

- Above normal temperatures expected through next week with upper
  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 Area

&&

.SHORT TERM /Through Sunday/...
Issued at 237 PM MDT Sat Jun 22 2024

Current radar shows showers and weak embedded storms developed over
the northern foothills, northern plains, and mountains this
afternoon. Some of these have produced gusty outflow winds up to 40
mph. Showers/storms move eastward into the foothills and adjacent
plains and given the lower dewpoints will amount to little rainfall
and moreso light rain, virga, and brief gusty winds up to 45 mph in
the convective showers. Remaining showers dissipate early evening.

An upper level ridge remains over the region on Sunday with weak
synoptic subsidence. 700mb temperatures warm a few degrees from
yesterday and with plentiful sunshine, this will support high
temperatures in the mid to upper 90s across the plains and east I-25
corridor. This is the first day (of several) that will be this
degree (no pun intended) of heat. Marginal MLCAPE (< 500) develops
over the far east plains from a weak disturbance in flow to the SE.
Marginal instability develops over portions of the higher terrain as
well. Moisture will be fairly limited keeping precipitation chances
low, even in the more favored less stable areas. Isolated showers
and storms are possible for the higher terrain and east plains as
result, although low chance overall (<25%). Sounding profiles are
very dry at the surface on the adjacent plains with limited mid-
level moisture which will make it difficult for much activity to
make it eastward off the foothills. If they do, can see some
isolated showers with virga and brief gusty winds.

&&

.LONG TERM /Sunday night through Saturday/...
Issued at 237 PM MDT Sat Jun 22 2024

The broad upper level ridge remains in place across the southern
U.S. through midweek with hot temperatures and mostly dry conditions
through about midweek.

Monday and Tuesday will be especially hot. Models show low relative
humidities in the mid and upper levels of the atmosphere which will
limit the amount of afternoon cloud cover. Long, sunny days with
little relief from the late June sun are expected. Any showers or
thunderstorms that develop will be over the mountains. If a stray
storm were to move east off the mountains, it would produce only
gusty winds and no beneficial rainfall. Will proactively issue a
heat advisory for the Denver metro area for Monday and Tuesday
since it will be quite a prolonged hot, dry spell.

On Wednesday, the ridge begins to flatten/shift eastward as the mid
level low pressure system moves onshore in the Pacific Northwest.
Increasing southwesterly flow across Colorado will allow for a
little more mid and upper level moisture and an incremental increase
in afternoon cloud cover and scattered thunderstorms on the plains.
It will still be quite hot though.

Thursday and Friday, I trended high temps down a degree or two both
of these days. Think the NBM might be a bit too hot as the upper
level ridge shifts off to the east. West to southwest flow aloft
brings a bit more mid and upper level moisture into north central
and northeast Colorado. Thunderstorm activity increases for both of
these days and should have more cloud cover and a better chance for
thunderstorms across the plains, especially Thursday
afternoon/evening. Saturday brings some welcome relief from the
90s.

&&

.AVIATION /18Z TAFS through 18Z Sunday/...
Issued at 1147 AM MDT Sat Jun 22 2024

VFR conditions expected for the TAF period. Light N to NE winds
this afternoon. There is a low chance (< 20%) of an isolated
shower or storm later this afternoon after 21Z. They will likely
be high-based in nature resulting in virga and brief variable
gusts up to 35 kts and winds. Winds become southerly tonight at
07-12 kts. Dry conditions and light winds expected Sunday.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM Monday to 9 PM MDT Tuesday for COZ040.

&&

$$

SHORT TERM...Mensch
LONG TERM...Stark
AVIATION...Mensch