758
FXUS65 KBOU 160012
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
612 PM MDT Sat Aug 15 2026

.KEY MESSAGES...

- Another round of showers and thunderstorms this afternoon and
  evening. Heavy rainfall and flash flooding are the main threats
  today. A few thunderstorms could become severe, with strong
  winds and hail possible.

- Monsoon moisture lasts through Sunday, bringing scattered
  showers and thunderstorms again tomorrow.

- Warming and drying trend for Monday and Tuesday.

- Another active day possible middle of next week.

&&

.DISCUSSION /Through Saturday/...
Issued at 103 PM MDT Sat Aug 15 2026

The wetter weather pattern will continue on through this weekend.
For today, there is a risk for severe weather and flash flooding.
The eastern plains should be located near the right entrance region
of a jet over the central US with a small disturbance expected in
the flow aloft. GOES-19 satellite imagery shows a cirrus shield
currently over the mountains that could initially inhibit convective
development. Nevertheless, convective development is starting to
occur across the foothills and in Larimer county. We expect showers
and thunderstorms to develop across the foothills early this
afternoon and move into the I-25 corridor by mid-to-late afternoon.
These storms will then move off to the east in the late afternoon
and early evening.

The previously mentioned cirrus shield could hinder rain coverage
and/or push this timing a bit later. The biggest threat for today
will be heavy rainfall with some episodes of flash flooding possible
across the area. The Weather Prediction Center highlights the
foothills, I-25 corridor, and the eastern plains in a slight (2/4)
risk for excessive rainfall for today. Several ingredients are in
place for this threat. Thus, a Flood Watch is in effect from 2pm to
10pm this afternoon and evening. See the hydro discussion for more
details.

The Storm Prediction Center highlights the plains in a
slight (2/5) risk. MLCAPE values are forecast to be around 1000-1200
J/kg and 0-6 km shear will be around 30-40 kts. Large hail and
damaging winds are possible from storms today, with the highest
chances along the Palmer Divide.

Tomorrow will bring similar threats as today, though we expect less
coverage of thunderstorms. Thus, the threats will be more localized
in nature. MLCAPE and bulk shear values are forecast to be lower
than today. The highest chances for showers and thunderstorms
tomorrow should stay along/near the Palmer Divide, but there will
still be scattered storms possible for most of our plains.

High pressure will shift closer to our area for Monday and Tuesday
further lowering rain chances and raising temperatures to around
90 degrees for the plains. By Wednesday, high pressure should
shift off to the southwest, opening the door for a disturbance to
move through the flow aloft and bringing back some isolated to
scattered rain chances. This will only be a brief break as high
pressure will start to build over the Four Corners region.
Temperatures are expected to return to the low to mid 90s across
the plains for the end of the week and into next weekend.

&&

.AVIATION /00Z TAFS through 00Z Monday/...
Issued at 610 PM MDT Sat Aug 15 2026

Storms have mostly moved out of the Denver metro area, though some
lingering showers and wind gusts may remain this evening through
02Z. Winds will become light and variable behind today`s convection,
with some mild S-SW drainage starting around 09Z. The main concern
overnight and into the early morning hours, around 12-14Z, will be
low ceilings and potential fog (60% chance), particularly over KDEN.
Models are in fairly good agreement on moisture lingering in the low
levels at KDEN, prompting a TEMPO for fog and low visibility. Low
stratus could also be advected into the vicinities of KAPA and KBJC,
though confidence remains lower to the west of KDEN at this time.

Prevailing winds will remain light (<10kts) tomorrow. There will be
another chance for isolated showers and storms, mainly between 22Z
and 02Z. Like today, any thunderstorms may produce brief heavy rain
and strong wind gusts (30kts).

&&

.HYDROLOGY...
Issued at 103 PM MDT Sat Aug 15 2026

Several ingredients are in place for the excessive rainfall
threat today. PWATs values will be around 150% of normal. Warm cloud
layer heights will approach 5000 feet, allowing for rather efficient
warm rain processes. Easterly (upslope) winds are occurring which is
continuing to advect moisture into the area. Dewpoints should be in
the 50s for the I-25 corridor and low to mid 60s across the plains
this afternoon and evening. Significant portions of our area have
received 2 to 5 inches over the last 3 days, lowering flash flood
guidance. Although, storm motions should be a touch faster than
yesterday- around 20-25 kts. Any storms today could produce 1 to 2
inches in 30 minutes. Rainfall totals for today could be in excess
of 2 to 4 inches. Given the nature of these storms, there will be
varying rainfall totals across short distances. A Flood Watch is in
effect from 2pm to 10pm this afternoon and evening.

For tomorrow, moisture is expected to decrease- PWATs will drop to
about 100 to 125% of average. The flooding risk for tomorrow will be
lower than today and more isolated in nature. The Weather Prediction
Center only highlights the Palmer Divide in a slight (2/4) risk for
excessive rainfall for tomorrow, where storm coverage should be
highest.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 PM MDT this evening for COZ036-038>051.

&&

$$

DISCUSSION...MV
AVIATION...Striplin
HYDROLOGY...MV