695
FXUS65 KBOU 171145
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
545 AM MDT Sun May 17 2026

.KEY MESSAGES...

- Another active shower/storm day Sunday, although threat of
  severe weather is more uncertain.

- Rain and mountain/foothill snow increases Sunday night through
  Monday with much colder temperatures arriving.

- Accumulating snow for the mountains, and >70% chance of
  accumulation in the foothills. Only a few wet snowflakes
  possibly mixed in for the I-25 Corridor.

- One last spring freeze possible on some of the plains Monday
  night.

- Gradually drier with a warming trend through the end of next
  week.

&&

.DISCUSSION /Through Saturday/...
Issued at 207 AM MDT Sun May 17 2026

We`re looking at another day of scattered showers and thunderstorms,
with the potential for a few strong to severe storms in the
afternoon. The upper level trough to our northwest this morning will
be digging south and progressing east towards Colorado today. In the
flow ahead of the upper low, a disturbance or two will move over the
area. This will help trigger some convective activity today. At the
surface, a front will move into our northern counties this morning,
moving south and potentially stalling somewhere near our southern
counties by early this afternoon. Behind the front, north winds will
bring drier air into the plains. This drier air will lower
instability, making severe storms less likely. Areas near and just
ahead of the front will have higher instability and convergence
along the front as an additional lifting mechanism, making this
area the best chance to see strong to severe storms today. The
positioning of the front early this afternoon is still uncertain,
but looking at high res guidance, the areas most likely to see
severe weather this afternoon will be Lincoln and Washington
counties and the far northeast plains. The biggest concern with
any storms today will be hail, however we could see strong winds
and potentially an isolated tornado as well.

Storm chances will dwindle as we go into the evening, however rain
chances will stick around. The upper level trough will approach the
area late Sunday, moving over the area mid Monday. Strong lift ahead
of this trough combined with decent moisture will bring more
widespread precip chances to the area. As the showers and storms
move east of the plains early this evening, additional showers will
be moving into the mountains from the west. Snow levels will start
out on the higher end, with snow generally above ~10,000ft. However,
the snow level will be continuously dropping overnight and
throughout Monday, leading to a rain/snow transition for the
lower mountains elevations, foothills, and Palmer Divide early
Monday. We could start to see a few snow flakes mix in Monday
afternoon for the I-25 corridor and northern plains, however
accumulations look unlikely (

NWS BOU Office Area Forecast Discussion