249
FXUS65 KBOU 140927
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
327 AM MDT Fri Jun 14 2024

.KEY MESSAGES...

- More numerous thunderstorms and a greater severe storm threat
  this afternoon through late evening

- A return to hot and mainly dry weather this weekend into early
  next week.

- Snowmelt producing minor impacts from high streams. Gradually
  diminishing flows next week.

&&

.SHORT TERM /Through tonight/...
Issued at 327 AM MDT Fri Jun 14 2024

GOES-18 mid level water vapor imagery displays deeper moisture
arriving to Utah Colorado border this morning. This shortwave trough
will be the main driver for scattered to numerous showers and storms
across northeast Colorado. A few stations along the foothills and
plains present dew points ranging from 45-58 this morning. With
favorable thunderstorm conditions such as MLCAPE values between 1000-
1500 J/kg, and lapse rates near 7-8 C/km, there is a threat of
storms becoming severe this afternoon. The highest probability area
for severe storms sits east of I-25 corridor this afternoon.
Storms could begin as early as 1 PM MDT. Model soundings indicate
large DCAPE values between 700-1000 thus expect storms to produce
wind gusts up to 65 mph. Additional hazards such as large hail and
lightning could occur. Storm motion seems not significantly fast
thus there is still a threat of localized flooding given
precipitable water values are above normal near 1-1.5 inches. The
only limiting factor for severe storms would be our inability to
heat up this afternoon. Temperatures will remain cooler today.
Expect low to mid 80s this afternoon for the urban corridor and
plains; temperatures for the mountains and valleys hover between
60-75F. Severe storms should end across the plains a few hours
before midnight. It is possible a few showers will linger as the
short wave trough exits the eastern plains.

&&

.LONG TERM /Saturday through Thursday/...
Issued at 327 AM MDT Fri Jun 14 2024

The upper level trough will move eastward on Saturday with a drier
airmass across the area.  However, there will still be enough
instability for isold to widely sct tstms in the aftn thru the early
evening hours. Severe potential looks low but a few storms may
produce gusty. Highs on Sat will rise back into the lower to mid
90`s over nern CO.

For Sun into Mon, drier air in SW flow aloft will be over the area
with a sfc lee trough over ern CO.  Overall, it appears any tstm
activity will be very isold.  Highs both days will stay in the 90`s
over the plains.

Looking ahead to Tue, SW flow aloft will remain over the area. A
cold front will move across the area but timing is still somewhat
uncertain. At this point have gone with a blended solution and kept
highs in the lower to mid 80s over nern CO.  Tstm chances will
depend on how much low level moisture moves in behind front and
whether capping inversion can be broken.

For Tue night into Wed, another surge of cooler air may affect the
area.  The GFS is stronger with this feature vs the ECMWF.  The GFS
has highs only in the 70`s across the plains while the ECMWF keeps
readings in the lower to mid 80`s.  As far as the upper levels, the
flow aloft will remain SW.  Once again, tstm chances will depend on
how much low level moisture there is and the strength of the capping
inversion.

By Thu, SW flow aloft will continue.  The ECMWF has temps rising
back into the 90`s over the plains while the GFS has readings near
seasonal levels.  As for tstms, the GFS has low level moisture
increasing across the plains with decent instability. This results
in a good chc for aftn storms. On the other hand, the ECMWF is
drier with less instability so it has far less activity.

&&

.AVIATION /06Z TAFS through 06Z Saturday/...
Issued at 1133 PM MDT Thu Jun 13 2024

Winds should shift back into drainage through Friday morning. By
late Friday morning winds could shift north for a brief period
then shifting east by Friday afternoon. Thunderstorms will develop
as early as 19Z then continuing until 00-02Z for all terminals.
Winds will increase up to 35-40kts gusts. By Friday evening,
showers should push east out of terminals and drainage winds are
expected once more.

&&

.HYDROLOGY...
Issued at 327 AM MDT Fri Jun 14 2024

Precipitable Water (PW) values increase to between 1 and 1.5",
with the highest amounts over the northeast plains. Storms will be
more efficient rain producers leading to localized flooding
issues. Cameron Peak would be most susceptible to a minor flood
risk through this evening.

Elevated flows continue in the mountain streams, with Flood
Advisories remaining in effect for the streams above Granby and
Grand Lake. Remain alert of the dangers of water that is running
high and cold. Flows are expected to gradually decrease over the
weekend and through next week as the peak snowmelt is passing by.

&&

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

&&

$$

SHORT TERM...AD
LONG TERM...RPK
AVIATION...AD
HYDROLOGY...AD/RPK