199
FXUS65 KBOU 151734
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1134 AM MDT Fri May 15 2026

.KEY MESSAGES...

- Summerlike warmth continues today with isolated high based
  showers.

- Elevated to near-critical fire weather conditions today.

- Shower and storm chances will gradually increase this weekend
  through early Monday but some uncertainty as to where and how
  much.

- Accumulating snow likely (>70% chance) for the mountains as
  temperatures turn colder Monday.

&&

.DISCUSSION /Through Thursday/...
Issued at 217 AM MDT Fri May 15 2026

The thermal ridge over the area will weaken slightly for today,
allowing temperatures to drop a few degrees for this afternoon.
However, highs will still remain around 10 to 15 degrees above
normal for this time of the year. A weak shortwave is forecast to
move through the flow aloft to the south of our forecast area.
This could be enough lift to trigger some light showers across the
Palmer Divide this afternoon. However, with the current dry
surface airmass and DCAPEs around 1000 J/Kg these showers are
more likely to bring gusty winds than wetting rain.

Temperatures will continue to drop a few degrees each afternoon
through the weekend. Surface return flow will setup over our eastern
counties on Saturday, bringing moisture in from the Gulf. Dewpoints
are forecast to increase pretty significantly for Saturday
afternoon compared to Friday afternoon. This increase in moisture
combined with lift associated with a developing upper level
trough to our west and associated surface low could be enough to
spark a few thunderstorms Saturday afternoon. A dry line will
likely sit over our area Saturday afternoon marking the line
between the moist Gulf airmass and the drier airmass. Areas to the
east of the dryline will have a much higher chance at seeing
storms on Saturday, giving our eastern Colorado plains counties
the best chance of storms. Right now, high res models are all over
the place with where the dryline will set up in the afternoon, so
confidence is low in the westward extent of any storms. If storms
do manage to get going in our area, we could see a few become strong
to severe. MLCAPEs look to be around 1000 J/Kg, with decent shear
and strong lapse rates. These ingredients will lead to the
potential for a few supercells with large hail and strong winds.

The upper level trough will push closer to the area for Sunday. Models
have a strong surface low to our east on Sunday afternoon, with
moisture wrapping around into eastern Colorado. Once again,
instability will be high enough and shear will be strong enough
that we will have to worry about severe storms Sunday afternoon
and evening. The one thing we will have to watch out for is the
cold front late Sunday into early Monday. The front could help to
trigger storms if it moves through in the late afternoon/evening,
but if it comes too early it will hinder thunderstorm development.
The highest chance for storms will be in our eastern counties,
with uncertainty in how far north and west storms will be able to
initiate. Large hail and gusty winds will be the main concerns
again.

The upper level trough will strengthen and move eastward late Sunday
into Monday. This will be our best chance for widespread
precipitation. We`ll see frontogenesis with the cold front and
strong QG ascent behind the front/ahead of the trough. The best
chance for rain overnight Sunday into Monday afternoon will be in
our northern counties, with decreasing confidence as we go south.
The most likely rainfall totals for the plains during this time
period is a trace to around an inch, with the higher end amounts
expected in our northern counties. The mountains are expected to
pick up a few more inches of snow with this event, with snow
generally staying above 8500ft. Temperatures behind the front
Monday are tricky, with ensemble members ranging anywhere from the
mid 30s to upper 60s for a high at Denver. Right now, we`re going in
the middle with a high in the low 50s, but we may need to trend
temps down for Monday if models continue to come in cooler.

Temperatures will stay on the cooler side for at least a few days
behind the front, before highs start to creep above normal again.
There`s low end rain chances with a shortwave on Tuesday, but
coverage should remain on the lower end.

&&

.AVIATION /18Z TAFS through 18Z Saturday/...
Issued at 1128 AM MDT Fri May 15 2026

VFR conditions will prevail for all terminals through the TAF
period. Winds are likely to oscillate between N and ENE through
mid-afternoon, when a shift to SE flow is anticipated. A period of
higher gusts is still favored for KDEN in particular this
afternoon, beginning near 22Z. Expect a return to drainage winds
this evening, although these will become increasingly light and
variable overnight, thereby raising the uncertainty in the
prevailing direction.

For Saturday, winds will be dominated by a Denver cyclone setup,
favoring southerly flow for KAPA, light northerly for KBJC, and a
more uncertain mix of NE to SE flow for KDEN. Nonetheless,
scattered -TSRA look to develop early to mid afternoon, mainly
east of I-25, bringing potential for robust outflow winds.

&&

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

&&

$$

DISCUSSION...AP
AVIATION...BRQ

NWS BOU Office Area Forecast Discussion