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Area forecast discussion 
National Weather Service Pueblo Colorado
1150 am MST Wednesday Dec 17 2014

issued at 1144 am MST Wednesday Dec 17 2014

Ran a quick update to adjust afternoon highs for this afternoon.
Cloud cover...weak cold air advection and light winds have kept
most of the plains in the middle 20s to lower 30s...about 5-10
degrees cooler than the forecast was indicating. Expect most areas
across the plains to warm an additional couple of degrees...with
upper 20s to low 30s through this afternoon. Did not make any
changes to precipitation...the evolution appears to be on track
based on the latest high-res models. Mozley


Short term...(today and tonight)
issued at 430 am MST Wednesday Dec 17 2014

..light snow possible across most of the region through tonight...

Shortwave energy will eject out of of the upper trough located over
the Desert Southwest...with one wave moving across southern Colorado
today...and another glancing by southern Colorado tonight. Models show
deeply saturated soundings along the Continental Divide this morning...with
thickening cloud cover spreading eastward through the morning across
the southeast mts and plains. Snow will start to spread into the sangres
by middle morning...then across the remainder of the southeast
mountains and portions of the I-25 corridor by this afternoon as a
broad area of weak upglide spreads eastward. Overall forcing with
this system does not look all that strong. But southwest middle level
flow around 10 kts should provide some modest orographic forcing to
produce some moderate overall accumulations for the Southwest
Mountains by shortly after midnight. In addition...lapse rates aloft
steepen during the afternoon and could see some embedded convective
snow showers as well. Will hoist a Winter Weather Advisory for the
eastern San Juan and La Garita Mountains above 10000 feet...where
amounts of 4-8 inches will be possible. These are on the low side
of the advisory range.

Showers will spread eastward into the plains late this afternoon
through tonight as weak upglide spreads eastward ahead of the
system. A weak front will push into the southeast plains
today...with shallow easterly flow setting up by afternoon. 700 mb
winds briefly shift out of the northeast across the Pikes Peak region
..but magnitude is weak...Under 10 kts. This appears sufficient in
the models to focus a band of snow across Teller and northern El
Paso counties through midnight. Most likely scenario is for light
accumulations of an inch or two given the weak forcing and
upslope...and nam12 accumulations look anomalously high and perhaps
convectively contaminated. Local accumulations of up to 4-5 inches
is not out of the question...but grids have this confined to the
higher elevations above 11kft. Farther to the south...700 mb winds
remain more westerly (downslope) expecting lesser amounts for
the lower elevations of the wets and sangres. The central mountains
and the crest of the sangres above 11kft may fair a little better
with around 2-6 inches through tonight. Across the southeast
plains...should see spottier accumulations generally under an inch
with snow winding down towards morning as upglide shifts eastward.

Long term...(thursday through tuesday)
issued at 430 am MST Wednesday Dec 17 2014

Thursday...another trough will pass over the region during the
day. The southern branch of the trough will remain over New
Mexico...and a weaker northern branch will pass over Colorado.
Highest probability of precipitation will be over the Continental Divide region.
Anticipate only modest snowfall from this trough...and snowfall
totals remain below advisory criteria. Some light precipitation
could spread east of the Continental Divide given the rather moist
lower levels. Scattered probability of precipitation are confined to the eastern
mountains...with some isolated probability of precipitation extending eastward onto the
Interstate 25 corridor and plains. Any accumulations in these
regions will be light with the weak dynamics.

Friday through Tuesday...a pattern change commences with an upper
ridge developing near the West Coast and a mean trough in the
Midwest. A series of disturbances will move through the mean
northwest flow. Most of the precipitation will be confined to the
mountains of lake and Chaffee counties...where northwest flow
results in favorable orographics. Models suggest a weak
disturbance on Saturday...followed by a stronger disturbance on
Sunday...and another disturbance on Tuesday. Followed the CR
extended pop grids with scattered probability of precipitation over the mountains of lake
and Chaffee counties. Suspect probability of precipitation will eventually increase for
some periods when the strength and timing of the troughs are
better known. East of the Continental Divide...chances for
precipitation are low as persistent west to northwest winds will occur
in the lower levels. With Arctic air remaining to the north and
east of the region...temperatures will remain at or above normal.


Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 1028 am MST Wednesday Dec 17 2014

Kals...ceilings have been slowly lowering this morning with snow
expected to develop by 21z this afternoon. Ceilings and visible will be
reduced through this evening with MVFR to IFR conditions. Expect
any snow should dissipate this evening. Model data and soundings
indicate the potential for fog late tonight into Thursday morning
with reduced visible and ceilings.

Kcos and kpub...ceilings have been slowly lowering through the
morning. It looks like there is a low potential for light snow at
both locations this afternoon into this evening...with lower
confidence at kpub. MVFR to IFR conditions are possible through
this evening at both locations. Improving conditions are forecast
for later tonight into Thursday morning. Mozley


Pub watches/warnings/advisories...
Winter Weather Advisory until 3 am MST Thursday for coz066-068.



short term...knots
long term...pgw

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