National Weather Service Forecast Discussion

597
FXUS65 KBOU 240235
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
735 PM MST Thu Jan 23 2020

.UPDATE...
Issued at 735 PM MST Thu Jan 23 2020

There is an area of mid cloud over the eastern plains. Models
shows that this area shifts east and north overnight, but hangs on
for much of northeast Colorado through the night. Adjusted the
sky coverage to reflect this. Also nudged PoPs up in the mountains
where radar indicates it is snowing. No other changes are planned
to the forecast.

&&

.SHORT TERM...(This evening through Friday)
Issued at 218 PM MST Thu Jan 23 2020

A shortwave trough over the Central Plains will continue to drift
eastward tonight and tomorrow while a flattening ridge moves over
Colorado. This ridging, along with a decrease in moisture, should
decrease the coverage of snow showers in the mountains later
tonight and Friday. Additional accumulation by tomorrow evening
should be less than an inch.

700mb temperatures will increase to near 0 degrees Celsius across the
plains tomorrow afternoon under the ridge aloft. This, along with
light winds at the surface, will allow highs to reach the low to mid
50s with dry conditions.

Upper level moisture will increase ahead of an approaching trough
tomorrow afternoon. Cloud cover will develop but snow showers in the
mountains should mostly hold off until the evening.

.LONG TERM...(Friday night through Thursday)
Issued at 218 PM MST Thu Jan 23 2020

For the weekend, a quick moving shortwave will push through the
region bringing light snow to the higher elevations Friday night
into Saturday morning. Model cross-sections show shallow moisture
with this system and weaker lapse rates in the 5 to 6 C/km range.
With the lack of lift provided by an upper level jet snow will be
light in nature and accumulations will be on the lower end. At this
time models are saying 1 to 3 inches is possible for the higher
elevations and west-facing slopes and less than an inch for mountain
valleys. With the orientation of the upper-level flow pattern the
plains will stay dry with increased downsloping. Snow will end by
mid-day Saturday as warm air advection increases under a flat ridge
that extends through Sunday. Temperatures will be on the cooler side
behind the shortwave with highs in the upper 40s to lower 50s on the
plains and teens and 20s across the high country.

For next week, an upper level trough will push onshore and into the
central and northern high plains by Monday morning. Models are not
showing a ton of moisture with this feature and it is relatively
quick moving. There is some decent QG associated with the trough as
it progresses southeastward into early Tuesday and closes off over
the TX panhandle. Models seem to be a tad more excited about
bringing a slight chance of precipitation to the plains with the
surface low dropping south and pulling in some cooler air. Depending
on timing of the precipitation and cooler air, it could start out as
rain with a quick changeover to snow later in the day on Monday.
Will continue with slight chance pops with conditions improving
through the morning Tuesday as the system pushes further eastward.
Temperatures will cool with highs closer to seasonal normals with
40s across the plains and 20s in the high country.

Flat ridging will return for Tuesday night into Wednesday as another
trough forms across the western coast and moves into the Great Basin
by mid-day Wednesday. This system is a bit far out to pinpoint
details but could bring another round of snow for the high country
Wednesday into Thursday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 735 PM MST Thu Jan 23 2020

VFR conditions will prevail through Friday with mid and high
clouds at times. Winds are expected to remain a southerly
component through 18Z Friday. A Denver Cyclone is expected to form
over Denver and bring easterly winds to KDEN. However, wind
direction will be somewhat uncertain after 18Z Friday because of
the Denver Cyclone.

&&

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

$$

UPDATE...Meier
SHORT TERM...Danielson
LONG TERM...Bowen
AVIATION...Meier

NWS BOU Office Area Forecast Discussion