091
FXUS65 KBOU 190005
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
605 PM MDT Tue Jun 18 2024

.KEY MESSAGES...

- Cooler through Wednesday with scattered showers and a few
  storms.

- Scattered thunderstorms Thursday into Friday

- Turning hot and drier this weekend through early next week

&&

.SHORT TERM /Through Wednesday/...
Issued at 141 PM MDT Tue Jun 18 2024

Cooler temperatures have settled in across the forecast area
today after a cold front swept through the region earlier this
morning. As the troughing pattern continues over the western CONUS,
there is a slight chance we get some weak rain showers or an
isolated storm to develop over the higher terrain this afternoon.
Current water vapor imagery indicates low level moisture is lacking
at this time, but looking upstream, low and mid level moisture looks
to be heading our way.

The better chances for precipitation will be overnight tonight and
tomorrow as the trough shifts eastward and a 90 kt jet will be in
place to provide upper level support to northern CO. CAMs indicate
banded precipitation spreading across the plains and continuing into
tomorrow. Forecast soundings also show a dry to start moisture
profile becoming increasingly saturated as low level flow will be
from the southeast, allowing for moisture support from the Gulf.
With the increasing moisture in place, some lower level stratus
are expected to help keep Wednesday`s high temperatures on the
cooler side. Temperatures are forecast to be 10-20 degrees below
the norm and will likely struggle to reach the 70s across forecast
area.

&&

.LONG TERM /Wednesday night through Tuesday/...
Issued at 230 PM MDT Tue Jun 18 2024

Models are in very good agreement overall with regard to the
weather pattern.

With more moisture and higher precipitable water values,
scattered showers and a few storms will work their way eastward
across the plains through tomorrow evening. Most of these should
be ending by late evening in/near the mountains with some drying
aloft noted, but linger over the eastern plains with low level
850-700 mb theta-e advection.

For Thursday, the airmass should moisten a bit further across the
area with deepening southerly flow. There are indications a
little of this starts to peel off the easterly wave (broad
circulation around Potential Tropical Cyclone One) in the western
Gulf of Mexico. We`ll also be returning to warmer temperatures,
which gives us more instability and probably an area of 1000-1500
J/kg MLCAPE over the northeast plains. Thus, a couple stronger
storms would be possible, and perhaps an isolated pulse severe
storm.

By Friday, there`s a better chance some of this tropical moisture
spreads northward across the forecast area and onto the western
slope of Colorado. This would keep at least scattered shower and
storm coverage in the forecast in/near the mountains, along with
adding a threat of locally heavy rainfall. It appears an embedded
shortwave could be arriving a little late for higher storm
coverage, but something to keep an eye on for Friday afternoon and
evening.

For Saturday, the above shortwave will be passing to the east of
Colorado, resulting in drying and subsidence through the weekend.
Ensembles are in good agreement with that timing, and the
subsequent mid level ridging over the Central Rockies and Great
Basin into early next week. The combination of the ridge, drier
airmass, and westerly flow aloft all supports a return of hot
temperatures for the lower elevations, with mid and upper 90s
expected for the plains and I-25 Corridor for Sunday, Monday, and
Tuesday. There could still be enough moisture under the ridge for
scattered mountain convection, and isolated storms on the plains
each afternoon/early evening. But overall these would be high
based with gusty winds and mainly light rainfall.

Finally, depending on the fire intensity near Ruidoso, New
Mexico (it is flaring up again this afternoon), the HRRR Smoke
shows some smoke spreading across Colorado Thursday.

&&

.AVIATION /00Z TAFS through 00Z Wednesday/...
Issued at 541 PM MDT Tue Jun 18 2024

There will be a few showers in the vicinity of the terminals this
evening but they are not expected to impact operations. Any
ceilings that would form will be elevated and not significant.
Winds will not be the typical drainage but will be ESE at DEN and
APA.

Late tonight and into tomorrow morning, there will be better
moisture advected in from the east which may lead to status
development. The limiting factor that could keep stratus away from
the terminals would be the very dry air that is in place in this
post-frontal airmass. But given pattern recognition, there is
usually stratus that develops shortly after sunrise on setups like
this and the stratus can last for the entire morning.

The stratus will breakup around midday leading to some sunshine
and gusty SE winds at DEN and APA. There will be showers and
perhaps a couple thunderstorms tomorrow afternoon and evening. It
is unlikely these would produce much of an impact as they will be
elevated and likely won`t produce strong winds at the surface.

&&

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

&&

$$

SHORT TERM...Bonner
LONG TERM...Barjenbruch
AVIATION...Danielson