443
FXUS65 KBOU 121811
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1211 PM MDT Wed Jun 12 2024

.KEY MESSAGES...

- Above normal temperatures and mostly dry weather are expected
  today and Thursday.

- Snowmelt producing minor impacts from high streams, mainly in
  Grand County.

- Slightly cooler conditions will arrive Friday and Saturday with
  scattered showers and storms. Some of these storms could be
  strong to severe along the plains with heavy rain on Friday.

&&

.UPDATE...
Issued at 1208 PM MDT Wed Jun 12 2024

Convective cloudiness is developing over the high country at this
time. Nothing on the radars yet. Temperatures over the plains
have already reached 90F in some place. The temperatures at DIA in
Denver is 13 degrees F higher now than it was yesterday at the
same time. For this update, will make a few wind and sky fixes,
minor overall.

&&

.SHORT TERM /Through tonight/...
Issued at 334 AM MDT Wed Jun 12 2024

Warmer and drier air will be over Colorado today. We should be too
dry for any substantial convective development, but there is still
a sliver of mid level moisture streaming in from the west,
evidenced by some thin convective clouds lingering around Grand
Junction at this hour. So we`ll likely have some development of
clouds/virga/sprinkles in the mid afternoon through early evening
hours. Hard to say if there will be enough rain generated to make
for much wind. The models say there will be almost no CAPE over
the western half of our area, although there obviously is a little
bit. Further east, there`s a little better surface moisture and
there could be a few more substantial thunderstorms in the early
evening hours that could generate near-severe wind gusts but not
much else.

Forecast highs look good, mainly mid 90s on the plains. We`re
nearing heat advisory criteria given that it`s the hottest day so
far, but we`re not quite there. We increased the late afternoon/evening
cloud cover a bit but kept PoPs below 15 percent.

&&

.LONG TERM /Thursday through Tuesday/...
Issued at 334 AM MDT Wed Jun 12 2024

Above normal temperatures continue Thursday across the region. An
upper level high remains south of Colorado keeping moisture
limited. Cross sections display zonal flow Thursday morning. There
is enough instability of ML CAPE values between 200-400 J/kg to
lead to an isolated shower or storm mainly east of the I-25
corridor. Any storm will likely remain sub-severe and could
produce small hail. A front sweeps through early evening which
should end any additional storms. Thursday afternoon highs
approach the low to mid 90s for the plains while the mountains and
valleys range from the low 70s to low 80s. This pattern will
likely lead to additional snowmelt on the higher peaks increasing
watershed flows.

As the high pressure system breaks down, an incoming shortwave
trough brings additional moisture and forcing to allow scattered
to numerous storms and showers to occur throughout our CWA. Long
skinny model soundings and PWATs increasing between 0.80-1.00 inch
may lead to localized flooding mainly for the urban corridor and
plains. There is some uncertainty in the severe threat location
and lack of shear. Friday afternoon could start as a few strong to
severe storms in the plains then becoming more of a heavy
rainfall event by the evening hours.

This weekend, ensembles favor temperatures bouncing back above 90
across the urban corridor and plains. Generally, thunderstorm
coverage remains isolated for northeastern Colorado.

&&

.AVIATION /18Z TAFS through 18Z Thursday/...
Issued at 1208 PM MDT Wed Jun 12 2024

Models show weak normal diurnal wind patterns at DIA into
Thursday morning. Will leave precipitation and the associated
gusty variable outflow winds out of the TAF for now. There will be
no ceiling issues.

&&

.HYDROLOGY...
Issued at 334 AM MDT Wed Jun 12 2024

Elevated flows continue across the upper Colorado River basin in
Grand County, with Flood Advisories in effect for streams above
Granby and Grand Lake. Remain alert of the dangers of water that
is running high and cold. Flows may increase over the next few
days as hot temperatures are expected followed by showers on
Friday.

&&

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

&&

$$

UPDATE.......RJK
SHORT TERM...Gimmestad
LONG TERM....AD
AVIATION.....RJK
HYDROLOGY...AD/Gimmestad