148
FXUS65 KBOU 191825
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1225 PM MDT Wed Jun 19 2024

.KEY MESSAGES...

- Continued cool today with scattered showers and a few storms.

- Scattered thunderstorms Thursday and Friday.

- Hotter and drier this weekend into early next week.

&&

.UPDATE...
Issued at 1010 AM MDT Wed Jun 19 2024

GOES-16 satellite imagery shows a mixture of clouds across the
forecast area this morning. With persistent cloud coverage
expected throughout the day, max temperatures were lowered a few
degrees, especially along the Palmer Divide and adjacent plains to
account for the lack of surface heating. The rest of the current
forecast looks to be intact, so will leave as is.

&&

.SHORT TERM /Through tonight/...
Issued at 308 AM MDT Wed Jun 19 2024

Persistent SW flow aloft will remain over the area today thru
tonight.  At the sfc, high pres will slowly move eastward allowing
for the low level flow to become more southeast by aftn, across the
plains. As a result, should see deeper low level moisture to the
east and southeast advect into the area.

Overall, can`t find any defined disturbance embedded in the SW flow
aloft to help enhance convection this aftn.  So it appears will have
to rely on convective temps being reached.  Most of the plains will
have low level cloud cover in place thru the aftn so this would
prevent convective development.  Portions of the higher terrain
should reach convective temps this aftn with sct showers and tstms
developing.  Outflow boundaries from this activity could trigger
some activity along portions of the I-25 Corridor by late aftn.
Overall, CAPE at lower elevations will be fairly minimal unless
temps rise into upper 75 to 80 degree range.  At this time, have
kept the highest pops over the higher terrain with lower chances
elsewhere.  Highs this aftn, will be mainly in the 60`s across the
plains.  However, some areas may not rise above 60 degrees where low
level cloud cover is expected to persist thru the aftn.
Meanwhile, around the Denver area readings may rise into the
lower 70s if cloud cover breaks up.

For tonight, will continue to see an increase in low level moisture
across the plains. Should see a warm air advection pattern
develop overnight. This could lead to a chc of nocturnal storms
overnight over portions of the plains, however, confidence isn`t
high as to overall coverage. Thus have kept pops mainly in the chc
category due to uncertainty.

&&

.LONG TERM /Thursday through Tuesday/...
Issued at 402 AM MDT Wed Jun 19 2024

A strong ridge of high pressure over the eastern United states is
expected to push westward Thursday and Friday. This will bring a
return to summer heat for the forecast area.

Models keep southwesterly flow aloft over the forecast area Thursday
through Friday night.  The QG Omega fields also continue to indicate
weak upward synoptic scale energy for the CWA through the period
with perhaps slightly stronger energy Friday night as a weakening
upper level trough moves across. In the lower levels models show a
pretty weak pressure gradient across the state with weak low
pressure east of the mountains. Southerly low level winds will
dominate over the plains on Thursday with a weak cold behind and
northeasterly winds on Friday.

Moisture will increase on Thursday with precipitable water values
climbing into the 0.80 to 1.40 inch range by late in the day.  With
temperatures expected to be about 20 degrees warmer than today`s
readings, there is fairly decent CAPE progged. Expect better
instability on Thursday compared to today. Will go with 20-50%
pops for most of the CWA with a few strong storms possible.

Moisture looks just as prevalent on Friday and Friday night with
precipitable water values as high as 1.50 inches over the plains.
Temperatures by be a bit cooler than Thursday`s with some models
showing a weak cold front to move into the plains.  The CAPE looks
pretty good. Will go with 20-70% pops in the afternoon and evening
with highest values in the mountains and foothills.  Models also keep
some precipitation going overnight in the alpine areas. Storms may
not be as strong than the Thursday storms.

For temperatures, Thursday`s highs are expected to be 6-11 C
warmer than today`s highs. Friday`s reading look to be a tad
cooler than Thursday`s highs.

For the later days, Saturday through Tuesday, the models continue to
move the upper ridge westward into the southwestern/south central
United States by Sunday. This upper ridge looks to stay there
much of next week. Hot temperatures will be the main weather story
those four days, especially over the plains where mid and upper
90s are expected. The chance of rain and thunderstorms will be
minimal over the plains all four days, with slightly higher
chances over the alpine areas.

&&

.AVIATION /18Z TAFS through 18Z Thursday/...
Issued at 1149 AM MDT Wed Jun 19 2024

Ceilings continue to fluctuate this morning at and around the
5000-8000 ft range. This is expected to continue with a pronounced
lifting not anticipated until later tonight. The persistent cloud
coverage has kept temperatures cool across the area and winds
have become increasingly gusty a little ahead of schedule, which
are expected to keep a gusty and southerly component through the
evening at DEN/APA. The latest guidance shows potential for winds
to gust in the low 30kt range at DEN/APA. There is low probability
that a thunderstorm passes near APA this afternoon, however, with
the persistent cloud coverage and low instability, showers are
the most likely scenario, so have left out of the TAF.

With greater instability over the higher terrain this afternoon,
have put VCTS at BJC as a storm may develop over the high country
and move east across the area. There is still a chance this
doesn`t happen with the current cloud cover. Winds at BJC look to
become variable around 4Z tonight and guidance shows this
continuing through the morning. There is a chance a Denver Cyclone
develops and N/NE winds setup. Or southerly winds may be another
option. Either way, winds are expected to stay light for either
scenario.



&&

.HYDROLOGY...
Issued at 404 AM MDT Wed Jun 19 2024

There will be minimal threat of flash flooding in the burn scars
this aftn especially over Cameron Peak and Williams Fork. A
limited flash flood threat will continue Thursday and Friday.

&&

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

&&

$$

UPDATE...Bonner
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...Bonner
HYDROLOGY....RPK/RJK