National Weather Service Forecast Discussion

Thornton Weather Forecast   
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167
FXUS65 KBOU 150019
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
619 PM MDT Tue Apr 14 2026

.KEY MESSAGES...

- Numerous rain showers with snow showers above 7000-8000 feet MSL
  will continue through this evening. Rain showers linger
  overnight across the northeast plains.

- Locally critical fire weather conditions over the plains
  Thursday afternoon.

- Next system moves in Friday with much colder temperatures and
  snow for most locations.

- Hard freeze likely Friday night and into Saturday morning with
  lows in the upper teens to mid 20s.

&&

.DISCUSSION /Through Tuesday/...
Issued at 227 PM MDT Tue Apr 14 2026

Water vapor satellite imagery shows the upper level trough
tracking east across Utah. The trough will continue tracking
eastward through tonight. Numerous showers and isolated
thunderstorms will continueahead of the trough. Rain and snow
showers will taper off this evening over the higher terrain and
along the Front Range as the trough shifts over northeast
Colorado. The snow level will be between 7,000 and 8,000 feet MSL.
An additional 2 to 6 inches of snow is expected in the mountains.
The rain showers will linger through the night over the northeast
plains. Locally, up to half an inch of rainfall is possible over
the northeast plains under the deformation zone.

Cool northwest flow aloft will prevail Wednesday behind the
exiting trough. High temperatures will reach the mid 60s to lower
70s across northeast Colorado. Flow aloft backs to the southwest
Thursday ahead of the next storm system. This will bring warmer
temperatures and continued dry conditions. South to southwest
winds will increase as flow aloft increases and a surface low
forms over Wyoming/northeast Colorado. The strongest winds, with
gusts up to 40 mph, are expected over the mountains. Over the
plains, the stronger winds will be found south of I-70.

An upper level trough will track across the Central Rockies on
Friday. Models are in good agreement that this trough will bring
widespread light precipitation (less than half an inch) and cold
temperatures. There are slight differences between the models
regarding strength and timing, which could nudge amounts up or
down. Precipitation may begin as rain across the plains, but
theairmass quickly cools with snow expected Friday afternoon.
Temperatures at 700mb fall to -8 to -12C, which is plenty cold
enough for snow. As previouslydiscussed, precipitation amounts
are generally expected to be light with snowfall amounts less than
3 inches across the plains. In addition to the needed
precipitation, this system will be very cold. Overnight lows are
expected to fall into the lower to mid 20s. Low lying areas will
likely see colder temperatures, with readings in the 15 to 20
degree range. Saturday morning temperatures will be the coldest
since mid March. Above-ground irrigation lines may be damaged
Friday night and Saturday morning due to the hard freeze. It`s
best (safest) to disconnect hoses and drain aboveground
irrigation lines aheadof time.

The upper level trough shifts east of the region by Saturday
morning, leaving a dry northwest flow aloft in its wake. After
Saturday morning`s cold start, temperatures climbed into the 50s
across northeast Colorado. A little below average for this timeof
year. Sunday through Tuesday, upper level ridging builds over
the Central Rockies for Sunday and possibly into Monday. Once the
ridge shifts east of the region late Monday or Tuesday, southwest
flow aloft will prevail. All three days are expected to be warm
and dry. Sunday will be the coolest withhighs in the upper 60s to
lower 70s. Slow warming continues early next week and by Tuesday
highs over northeast Colorado are expected to reach the upper 70s
to lower 80s. Windy conditionsare not expected under this
pattern, but if they occur, they would raise fire weather
concerns.

&&

.AVIATION /00Z TAFS through 00Z Thursday/...
Issued at 617 PM MDT Tue Apr 14 2026

Recent radar imagery shows light rain showers in the vicinity of
KDEN and KAPA at this time, as well as WNW winds gusting to 25KT.
We have extended the TEMPO for -SHRA until 03Z, given that it is
still possible for brief ceiling lowerings (5000-6000ft) and gusty
winds to occur with the ongoing shower activity. Ceilings will
improve later tonight after rain showers and virga move out of
the area, and winds will turn variable with some weak drainage
winds possible in the early morning hours.

Winds on Wednesday afternoon will stay W-NW at all three TAF
sites. There is a slight chance (30%) for some periods of gusts in
the 20-25KT range at KBJC late in the afternoon due to favorable
conditions for downsloping winds, but we opted not to include
gusts in the TAF at this time due to low confidence.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 8 PM MDT this evening for COZ247.

&&

$$

DISCUSSION...12
AVIATION...AA

NWS BOU Office Area Forecast Discussion