Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 041749
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1049 AM MST Sun Dec 4 2016

.UPDATE...
Issued at 1049 AM MST Sun Dec 4 2016

No changes to the forecast at this time. Skies are mostly clear
across the forecast area and temperatures have warmed to the lower
and mid 40s at some locations, and remain in the 30s elsewhere.
Moisture will begin increasing over the mountains later tonight as
west-northwest flow aloft begins to strengthen.

&&

.SHORT TERM...(Today and tonight)
Issued at 211 AM MST Sun Dec 4 2016

Colorado is under a strong northwest flow pattern today following
a weak upper trof, which is now moving through the central plains
states. With this strong flow pattern, have seen wind gusts in
the 25-45 mph range in the mountains and foothills through the
night. Expect these winds to increase even more by later this
afternoon and evening as cross barrier flow increases to 50-60kt
at mountain top level with strong upper jet across Wyoming.
Shear profile improves for amplified mountain wave conditions
tonight but stability is marginal and there is not much in the
way of large scale subsidence. Considered a high wind watch for
tonight, but appears strongest winds will remain over higher
mountain peaks and exposed higher foothills with gusts up to 70
mph. Certainly still bears watching, but window for high winds is
small and areal extent would be minimal.

Moisture will be increasing tonight with areas of light snow
developing over the northern mountains. Initial accumulations will
be light as moisture depth is initially shallow, low lapse rates
and lack of any large scale ascent.

Across lower elevations, skies will be mostly sunny for much of
the day along with warmer temperatures. Some wave cloudiness
expected to develop later this afternoon and tonight.

.LONG TERM...(Monday through Saturday)
Issued at 211 AM MST Sun Dec 4 2016

Light snow and strong winds will continue over the mountains
Monday morning. Gusts in the 60 to 70 mph range may be common in
the upper foothills and high mountains. A longwave trough will
push down out of western Canada Monday with the upper jet sliding
over the state before splitting later that day. Temperatures will
be relatively warm for one more day with readings in the 40s and
50s over the plains and in the 20s and 30s over the mountains. A
cold front is progged to push down during the late morning to
early afternoon. Gusty west winds are expected ahead of this
front. This front, due to its origins may end up moving in faster
than forecast right now so will keep tabs on its movement. QG
vertical motion will be downward Monday and the best moisture
moves off to the northeast. Upslope flow and moisture is shallow,
so do not expect much moisture for the plains on Monday. However
good orographics and cold advection will likely bring 2 to 6
inches of snow to the higher mountains. Travel may be hazardous
over the mountain passes due to strong winds and snowfall.

Another shortwave around the upper trough will reinforce the cold
push Tuesday with a 130 kt jet pushing into the Great Basin and
into southern Colorado. Pacific moisture will be entrained in this
system and moderate upward QG motion is expected. This will bring
in moderate to heavy snow at times to the mountains and spread
over the plains. For now, its looking more like 4 to 10 inches
over the high mountains, this time with less wind. Over the
plains, temperatures will likely only warm into the 20s, and 2 to
4 inches of snow may fall. The jet may produce banding, and
therefore highly variable amounts may occur over a short distance,
with some locally heavier amounts.

Snow should diminish from west to east Wednesday morning as upper
ridging moves in from the west. Conditions should remain mainly
dry through Thursday as the ridge moves overhead, but continued
cold surface high pressure bring much colder than normal
temperatures to the area...by as much as 20 degrees colder for
this time of year. Wednesday highs may struggle to get out of the
teens for the plains and single digits for the high country, where
the lows Wednesday night under clear skies will likely be below
zero everywhere.

Southwesterly flow aloft ahead of another Pacific system will
push in for Friday and Saturday to bring warmer temperatures and
the next chance for snow for the area. Max temperatures will
return to near normal.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1049 AM MST Sun Dec 4 2016

No significant aviation impacts through the next 24 hours. Cloud
heights will remain above 10,000 feet and visibilities will be
unlimited. Winds will be out of the south through today and then
west to southwest tonight.

&&

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

$$

UPDATE...Dankers
SHORT TERM...Entrekin
LONG TERM...Kriederman
AVIATION...Dankers



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