Castle Rock, Colorado 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

739
FXUS65 KBOU 221147
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
447 AM MST Sun Dec 22 2024

.KEY MESSAGES...

- Warm and dry today.

- Periods of light snow in the mountains late tonight into Monday,
  Wednesday, and Friday with some travel impacts.

- Slight chance of rain or snow showers at lower elevations on
  Christmas afternoon and evening with minimal impacts.

&&

.SHORT TERM /Through Tonight/...
Issued at 418 AM MST Sun Dec 22 2024

It is pretty mild for the middle of the night in the later part of
December in Denver, Colorado. It has been down to 43 so far today.
It should stay pretty mild through sunrise with the southwesterly
drainage winds at DIA expected to continue. Also there is another
growing lenticular cloud getting over the airport at this time.
The record high low temperature for December 22nd in Denver is 41
degrees set in 2005. We`ll see? The western suburbs are still in
the 50s at this time.

Models have flat upper ridging for the CWA today and tonight. Cross
sections show decent mid and upper level moisture to stay over the
CWA for the first two periods.  There is a shallow batch of low
level moisture progged to get over the mountains, but not until
after 06Z-09Z. There will be limited orographic snow showers in
the high mountains, nothing significant. I pushed the alpine snow
showers back to after 06Z tonight based on model`s moisture
availability. No pops for the plains and foothills. For
temperatures, readings should stay well above seasonal normals for
the CWA. The plains should see highs in the lower and mid 60s.
Denver`s record high is 70 degrees for December 22nd.

&&

.LONG TERM /Monday through Saturday/...
Issued at 418 AM MST Sun Dec 22 2024

Not a lot to change in the longer term. There will be quite a bit
of cloud cover Monday along with a little puff of cooler air. It
still looks like there`s some weak lift associated with a jet
streak moving from the mountains onto the plains, a bit faster now
in the afternoon/evening. Nudged the PoPs up a little late in the
day as there could be an attempt at light showers moving onto the
plains for a few hours as this goes by.

There`s pretty sharp warming aloft/subsidence/clearing behind this
Monday night, and Tuesday is looking more clearly like a break
between systems with temperatures recovering, so we`ve warmed the
forecast highs back to around Monday`s readings.

Only minor changes for Wednesday`s system, there continues to be a
gradual slowing trend in the models. There`s some variation in the
strength, but this looks like it mostly affects the gradients on
the southern side of the system. NBM PoPs with a chance of rain or
snow showers in the late afternoon and evening seem alright.
Probably just rain over most of the plains, there`s a chance it
could be cold enough for a small amount of snow on warm ground in
Denver. We found two Christmas Days in 152 years of Denver weather
history with rain but no snow, 1892 and 1922. The latter had over
half an inch of rain! If we get anything this time around it would
probably be closer to a tenth of an inch.

There`s a bit more spread on the upstream trough which is quick
moving and could be fairly sharp dynamically but still doesn`t
have much cold air with it. Stronger solutions would bring a
shower band across during the day Friday, enough for a chance of
rain at lower elevations. Weaker solutions would probably limit
the precipitation to the mountains. Better agreement on ridging
for the weekend with a bit of warming.

Throughout temperatures will remain mild for the season, and even
in the mountains the occasional snow will be light. There could be
brief travel impacts in the high country, but for the most part
they should be minor.

&&

.AVIATION /12Z TAFS through 12Z Monday/...
Issued at 444 AM MST Sun Dec 22 2024

Normal drainage winds should give way to light west-northwesterly
winds at DIA by late morning, then to weak northeasterly winds by
late afternoon. Models are showing a weak surge of northerly
winds late evening, continuing much of the night. Normal, weak
drainage winds may eventually win out during the predawn hours of
Monday morning. There will be no ceiling issues.


&&

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

&&

$$

SHORT TERM...RJK
LONG TERM....Gimmestad
AVIATION.....RJK