229
FXUS65 KBOU 010020
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
620 PM MDT Tue Mar 31 2026

.KEY MESSAGES...

- Mountain snow will continue through Wednesday, with scattered
  rain showers possible over the plains this evening.

- Better chances for precipitation (50-70%) across the plains
  Wednesday afternoon and evening.

- A brief warm up on Thursday, but an unsettled pattern continues
  with another storm system possible Thursday night into Friday.

&&

.DISCUSSION /Through Tuesday/...
Issued at 322 PM MDT Tue Mar 31 2026

Current water vapor satellite imagery shows moisture being advected
into Colorado ahead of an incoming shortwave trough. Scattered
rain/snow showers are gradually developing over the mountains and
will continue through the evening. For the plains, hi-res
guidance is in good agreement of showers spilling over from the
high terrain later this afternoon and evening. For the most part,
expect light rain wherever the showers develop on the plains.
However, there is a chance of briefly moderate rainfall,
particularly the Palmer Divide, due to the Denver cyclone.

More meaningful QPF and widespread mountain showers are expected
overnight tonight and through Wednesday as QG lift increases with
the strengthening of the shortwave. However, the bulk of the
precipitation will stay west/southwest of our forecast area due to
the unfavorable southwest flow aloft. Despite that, guidance is in
good agreement of measurable snowfall for elevations above 9000-9500
ft, with total accumulations between 3-10" and localized higher
amounts at highest elevations. Due to the warm air mass that has
resided over the region, snow-to-liquid ratios will start off low
(6:1 to 10:1). However, the shortwave will bring in cooler air on
Wednesday, which will raise snow-to-liquid ratios up to 15:1 in some
mountains by Wednesday evening. Have continued the Winter Weather
Advisory for the mountains, with travel impacts likely during the
Tuesday evening and Wednesday morning commutes.

Along with the arrival of the shortwave Wednesday afternoon, lee-
cyclogenesis is favored to form over the plains, which will help
bring another round rain across the lower elevations. Modeled Skew-T
soundings show a couple hundred J/Kg of CAPE, which would support
moderate rainfall at times along with a couple rumbles of thunder.
However, QPF amounts remain generally unimpressive, with guidance
indicating less than 0.3". Precipitation should gradually end across
the forecast area overnight Wednesday as subsidence increases aloft.

Warmer and drier weather returns to the region on Thursday in
between systems. Guidance is in good agreement of temperatures
rising back up to the low 70s across the plains. Gusty southwest
winds at the surface will promote elevated fire weather conditions,
particularly for the eastern plains, where gusts up to 35 mph are
possible. With relative humidities expected to drop to the low teens
by Thursday afternoon, have opted to issue a Fire Weather Watch for
Lincoln county and portions of Elbert County, as those areas may not
receive measurable precipitation from the previous system. However,
if those areas were to receive widespread rain showers on Wednesday,
would opt to cancel the watch.

The next system is progged to arrive late Thursday/Friday morning,
with a 500-mb closed low trekking just north of Colorado. The best
chance for snowfall looks to be for our northern mountains, as QG
lift, upper level jet and mid-level frontogenesis line up the best.
A surface cold front will bring in cooler temperatures for Friday,
however no precipitation is expected on the plains, aside from an
isolated shower.

Weak ridging will return to the region over the weekend, with warm
and dry conditions through the beginning of next week.

&&

.AVIATION /00Z TAFS through 00Z Thursday/...
Issued at 618 PM MDT Tue Mar 31 2026

Scattered light rain showers are currently moving east over the
Denver area and ending by 03-04Z. Showers could briefly lower
ceilings to 6000-7000ft but otherwise ceilings above 10000ft can
be expected through tonight. Recent observations show a Denver
cyclone positioned south of DIA. While the exact evolution of this
cyclone is uncertain, we expect it to weaken or shift northwards
this evening before a push of strong southerly winds arrives at
KAPA and KDEN by midnight. Wind gusts in the 20 to 30kt range will
be possible with this surge of south winds.

N-NW winds will arrive around 19Z tomorrow as well as increased
moisture that will allow for the development of scattered rain
showers. Enough instability (300-600 CAPE) will be present for a
weak thunderstorm or two to develop, which is why we have included
a PROB30 for -TSRA. Gusty outflow boundaries could occur with any
showers that develop. However, the chance of a thunderstorm
passing over any airports is 10-20%.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 PM MDT Wednesday for COZ031-033-
034.

Fire Weather Watch from Thursday afternoon through Thursday
evening for COZ246-247.

&&

$$

DISCUSSION...MAI
AVIATION...AA

NWS BOU Office Area Forecast Discussion