609
FXUS65 KBOU 102157
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
357 PM MDT Fri Oct 10 2025

.KEY MESSAGES...

- Scattered showers and isolated thunderstorms through Saturday,
  mainly across the higher terrain.

- Near normal temperatures with chances for showers Sunday into
  early next week. This precipitation will fall as snow in the
  mountains and rain across the plains.

- Warmer, drier, and windier Wednesday and Thursday.

- Perhaps the first signal of a frost for lower elevations between
  October 19-21.

&&

.DISCUSSION /Through Friday/...
Issued at 346 PM MDT Fri Oct 10 2025

Water vapor shows a healthy amount of moisture streaming up from
the tropical eastern Pacific. In addition, there is a trough over
the West Coast of the US that is helping to provide forcing across
the Four Corners while streaming this moisture towards the area.
The GFS is forecasting precipitable water values that are 5
standard deviations above normal. So this is significant moisture
and there is a large area of Flood Watches to our west. However,
most of this moisture will fall in the mountain ranges to our
southwest and our forecast area will not receive significant
rainfall. Having said that, there will be multiple waves of
precipitation across our forecast area through Tuesday.

The first wave of precipitation is occurring right now with rain
ongoing in the mountains and virga across the plains. Visible
satellite shows a wide area of thick cloud cover and radar shows
increasing coverage of rain in the mountains and this trend is
expected to continue through much of the night. Since this is
tropical moisture, the vast majority of the precipitation will
fall as rain over the mountains with the only exceptions being
ridges above 12,000 feet.

During the later part of the night and into tomorrow morning,
there may be a break in the moisture and precipitation. Another
wave of precipitation with the aid of a shortwave trough will
move across our forecast area Saturday afternoon. The forcing
associated with this trough should be enough that rain will reach
the ground across the plains. PoPs were increased to have a
mention of rain in the forecast.

A trough with much colder air aloft will move over Colorado Sunday
morning. This will significantly decrease 700 mb temperatures by
7-10 degrees C. The 700 mb temperatures will reach below freezing
across the western slope and precipitation will transition to
snow above 9,000 feet. 1-4" of snow will occur in the Park Range
and western slopes of the Front Range mountains. Strong winds are
expected to develop with this frontal passage and gusts up to 60
mph are possible in the Front Range foothills with up to 45 mph
across the northern plains.

Another trough will be over the western US on Monday and Tuesday.
This will also bring moisture from the tropical Pacific and there
is a chance that it spreads precipitation across our entire
forecast area.

On Wednesday and Thursday, there will be drier air that moves into
our forecast area ahead of the trough. Most ensembles are
indicating this could be a very mild day with strong southerly
winds. If there is no cloud cover, temperatures could reach near
record highs.

The ECMWF ensembles are finally starting to show a signal that the
first low elevation frost of the year could occur between October
19-21. This will have to be monitored as more than half the
ensembles also have precipitation during this time.

&&

.AVIATION /18Z TAFS through 18Z Saturday/...
Issued at 1217 PM MDT Fri Oct 10 2025

A DCVZ has setup to the east of the Denver metro. For most of the
afternoon, this boundary will be stationary with northwest or
northerly winds at all terminals. However, there is a chance that
this boundary moves northwestward towards APA and DEN. If this
were to occur, gusty southeast winds would develop at both
terminals. While the HRRR and other models have this boundary
pushing through the terminals, it seems unlikely it will until the
evening.

Otherwise, light showers will be near the airports throughout the
TAF period. These are high level showers and will have very little
impact at the surface. There will be drainage winds tonight that
will increase out of the southwest during the day tomorrow.

&&

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

&&

$$

DISCUSSION...Danielson
AVIATION...Danielson