364
FXUS65 KBOU 101644
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
944 AM MST Fri Jan 10 2025

.KEY MESSAGES...

- Very windy Front Range Mountains and Foothills tonight into
  early Saturday.

- Mountain snow late tonight through the weekend, with the
  heaviest amounts expected late Friday night through Saturday.

- Dry much of next week with a temperatures warming to near
  normals.

&&

.UPDATE...
Issued at 944 AM MST Fri Jan 10 2025

It was a chilly start to the day. The coldest temperatures were
in the mountain valleys where temperatures fell below zero and in
Park County, the low lying areas dropped to -20F to -30F. Adjusted
temperatures today to line up with the latest trends, which is to
cool some locations.

For tonight, winds increase and become strong over the Front
Range Mountains and foothills as an upper level trough dives south
across the Central Rockies. There looks to be about a 3 hour
window when winds approach High Wind Criteria (75 mph). A couple
of the windy locations may briefly top 75 mph, but widespread high
winds are not expected. Snow moves into the mountains late
tonight and becomes widespread early Saturday. Adjusted PoPs
slightly to better time the onset of snowfall.

&&

.SHORT TERM /Through Tonight/...
Issued at 409 AM MST Fri Jan 10 2025

Skies are nearly clear at this hour, though there are a few clouds
over Grand and Summit counties and even a few flurries. There`s
also some fog around Walden. Temperatures plummeted in the
mountains as expected, while there`s just enough of a breeze to
keep most of the plains around 10 above, with a few colder spots.
Pretty sure Antero Reservoir will come in as our cold spot, it`s
probably -20 there right now, with some other typical cold spots
down to -15.

The little bits of remaining moisture should be gone by mid
morning, then we`ll start to get some thin high cloudiness
drifting over, but still plenty of sunshine. We`ll have steady
warm advection and increasing mountain winds. Temperatures on the
plains will wind up being controlled by the snow cover, with highs
in the 30s in most areas but probably some lower 40s along the
foothills with a little west wind late in the day.

Tonight still looks promising for some wave amplification over the
Front Range. Maybe a small high wind threat, but gusts in the
40-60 mph range in exposed areas with up to 75 mph in the higher
elevations and the wave hot spots looks likely. By Saturday
morning the amplification profile is gone as cooling aloft and
increasing shear should end the amplification. Serious snow
doesn`t really get going until late night. There could also be
some light showers in the northeast corner by sunrise.

&&

.LONG TERM /Saturday through Thursday/...
Issued at 429 AM MST Fri Jan 10 2025

Upper troughing is expected over the forecast area Saturday
through Sunday night. The flow aloft will be fairly light and
mainly zonal Saturday through Sunday night. In the lower levels
there looks to be a brief period of upslope for the plains
Saturday, but by evening and continuing through Sunday night,
weak normal diurnal wind patterns are progged. The QG Omega fields
have decent synoptic scale upward motion for the CWA Saturday,
then weak ascent to neutral forcing Saturday night through Sunday
night.

There is fairly deep moisture over the mountains Saturday and
Saturday night, with less over the plains and very little in the
lower levels there. Moisture decreases Sunday, but there is still
enough around for light mountain snows. Moisture actually
increases over the western CWA Sunday night. For pops, will keep
the 75-100%s going in the mountains Saturday and Saturday night,
then 50-80%s on Sunday, decreasing into the 25-50% range Sunday
night. The snowfall totals will be fair Saturday and Saturday
night with up to 8 inches; the highest amounts over the Park
Range. Will leave the Snow Advisory highlight going there. For the
plains, will go with 10-40% pops mainly just on Saturday.

For the later days, Monday through Thursday, there is still weak
upper troughing over the CWA but the flow aloft is weak.  Upper
ridging moves in for the rest of the week with dry conditions and a
warm up.  Temperatures may even warm to seasonal normals by
Wednesday and Thursday, with 40s to lower 50s for highs.

&&

.AVIATION /18Z TAFS through 18Z Saturday/...
Issued at 944 AM MST Fri Jan 10 2025


VFR to prevail tonight and through at least 18Z Saturday. High
clouds will increase later today and tonight ahead of a storm
system. This system moves across the area late tonight and
Saturday, bringing lowering clouds for Saturday. Ceilings may fall
below 6000 feet after 18Z Saturday.

Winds for today look to stay southwesterly most/all of the day.
The southwest winds continue this evening. After 06Z, wind
direction becomes more challenging as a mountain wave and
downslope winds develop to the west of Denver.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 11 PM this evening to 11 PM MST
Saturday for COZ031.

&&

$$

UPDATE...Meier
SHORT TERM...Gimmestad
LONG TERM....rjk
AVIATION...Meier

NWS BOU Office Area Forecast Discussion