000
FXUS65 KBOU 091135
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
435 AM MST Sat Dec 9 2023

.KEY MESSAGES...

- Light mountain snow through this evening.

- Wind gusts to 45 mph eastern plains today.

- Potential for high winds up to 80 mph in the higher mountains
  and Front Range Foothills on Sunday.

&&

.SHORT TERM...(Today and tonight)
Issued at 306 AM MST Sat Dec 9 2023

Snow will continue to decrease through the early morning, ending
by sunrise across the foothills and Urban Corridor. Left in the
snow`s wake will be snow covered and slippery roads this morning.
The worst driving conditions will be found west of I-25 and into
the foothills and mountains. Speaking of the mountains, areas of
light snow are expected through the day due orographic lift caused
by the northwest flow. Additional snowfall is expected to be
light, less than 2 inches. Cross sections show that the moisture
slowly decreases through out the day and the snow will come to an
end this evening. It will be a chilly day under the north-
northwest flow aloft. Highs across northeast Colorado will be
mainly in the mid to upper 30s. Downslope off the Cheyenne ridge,
could push temperatures into the lower 40s from Greeley to Fort
Morgan. Expect gusty north winds across the eastern plains with
gusts to 45 mph.

Winds ramp up in the Front Range Mountains and higher foothills late
tonight as northwest flow aloft increases. A mountain wave may set
up late tonight, but a better chance for one Sunday morning. A quiet
night is expected across the plains with lows in the teens.

.LONG TERM...(Sunday through Friday)
Issued at 306 AM MST Sat Dec 9 2023

Main concern on Sunday is the high wind threat over the
higher mountains and Front Range foothills. There will be a strong
northwest flow pattern in place while the strong 105+kt jet streak
remains north of Colorado across Wyoming. Cross sections showing 40-
50kt cross barrier flow Sunday morning while mountain top inversion
strengthens after 12z between 700-750mb. Local wind programs
indicate pretty decent chances for high winds on Sunday while the
surface pressure gradient across the state tightens 12-17mb from GJT
to DEN. High resolution models showing gusts in excess of 70kt
Sunday morning then slowly decreasing Sunday afternoon. Given the
above parameters, a high wind watch is warranted for Sunday over
the higher mountains and foothills and will be issued with this
morning`s forecast package. A warming trend is also in the cards
Sunday with the increasing downslope flow and warming at 700mb
across lower elevations.

Given the persistent northwest flow pattern, there is enough
moisture for areas of light orographic snow showers in the
mountains, especially late Sunday into early Monday. Temperatures
will continue at seasonal normals. Forecast confidence decreases
through much of next week as the next upper trof develops into a
closed low somewhere over the Great Basin and desert southwest by
the middle of next week. Overall the majority of the models
(GFS/Canadian) keep the brunt of the energy and moisture south of
Colorado. However the European solution keeps the low further
north towards southwest Colorado which could mean more potential
snowfall for Colorado. Each run, however changes and not much
confidence in any one solution. Will keep a chance of snow in the
mountains for now but mainly dry across lower elevations through
the week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 435 AM MST Sat Dec 9 2023

Snow has ended at the Denver airports. Skies to remain sct-bkn
this morning before thinning some this afternoon. Ceilings through
15-16Z look to be 6000-8000 feet. Light west to southwest winds
will turn northerly 15-17Z as northerly winds aloft mix down.
Gusts to 25 knots will be possible at DEN, with stronger winds not
far off to the east. The northerly winds end by 00Z and become a
southerly drainage direction at DEN and APA. For BJC, light winds
are expect around 00Z, but gusty west winds may form overnight,
around 06Z with gusts of 25-35 knots possible.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...

High Wind Watch from late tonight through Sunday afternoon for
COZ033>036.

&&

$$

SHORT TERM...Meier
LONG TERM...Entrekin
AVIATION...Meier

NWS BOU Office Area Forecast Discussion