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Area forecast discussion 
National Weather Service Pueblo Colorado
404 am MDT Tuesday Sep 30 2014

Short term...(today and tonight)
issued at 343 am MDT Tuesday Sep 30 2014

..isolated mountain showers with seasonal temperatures...

System that moved through yesterday has brought a seasonal air mass
to southern Colorado. Today will be a seasonal fall day across the
area with a few mountain showers and isolated afternoon and evening
thunderstorms possible...mainly over the Continental Divide...and
mainly over the central mountains. Snow showers will be possible
above roughly 10000 feet today with local accumulations of an inch
or so possible at pass level and above.

An isolated shower or storm could drift off the mountains onto the
plains late in the day or early in the evening. But this would
really be the exception rather than the rule. In general...mostly
sunny or partly cloudy at times with seasonal temperatures today.

Current frost advisory for the San Luis valley continues to look
good for this morning. The valley has had some moisture over the
past couple days and temperatures are currently in the middle to upper
30s under clear skies. Dewpoints are currently in the lower 30s.
Expect temperatures to fall to near the dewpoints by morning...which
would mean lows near freezing...near saturated conditions...and thus
a frost. The valley will likely see another frost will
go ahead and hoist another frost advisory for then.

Long term...(wednesday through monday)
issued at 343 am MDT Tuesday Sep 30 2014

Not much change to the long range forecast with low ensemble
spreads and good operational model agreement through the extended

Wednesday and Thursday...a strong shortwave trough will drop south
out of the northern rockies and move across Colorado. Expect
isolated to scattered shower activity along the Continental Divide
Wednesday morning which will increase in coverage and spread east
into the Palmer Divide Wednesday afternoon. Afternoon instability
will likely produce at least a few thunderstorms Wednesday over
the mountains with lightning being the main threat. A strong cold
front is forecast to drop south across the eastern plains
Wednesday night into Thursday morning. Strong northerly winds are
expected behind the front...with 30 knots gusts possible out near the
Kansas border. Models slightly different in precipitation chances
for the plains. For now followed the GFS and European model (ecmwf) which have been
consistent. Expect widespread shower activity to spread across the
eastern plains behind the cold front Wednesday night and Thursday
morning with most locations seeing light precipitation. This
activity will clear from west to east by Thursday afternoon with
dry conditions across the region Thursday evening. It should be
noted that the NAM is a bit further north with its storm track and
keeps shower activity confined to areas north of Highway 50. This
will need to be watched. There will also likely be a few inches of
snow over the higher elevations Wednesday into Thursday as snow
levels fall to around 10 kft. Afternoon temperatures will warm
into the 70s on Wednesday...with 60s expected Thursday afternoon
for the lower elevations. Overnight lows Wednesday and Thursday
mornings will be cool...with upper 20s to lower 30s for the San
Luis valley...and 40s across the eastern plains.

Friday through Monday...the upper level pattern will become
amplified and stationary through this period...with an upper level
trough over the eastern Continental U.S. And upper ridge along the West
Coast. This will put southern Colorado under broad northwesterly
flow. Very little moisture will be across the area with dry
conditions expected through the period. Temperatures will also
warm...with afternoon highs in the upper 70s to lower 80s through
the weekend. Mozley


Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 343 am MDT Tuesday Sep 30 2014

Generally a dry westerly flow for much of the area over the next 24
hours...with VFR expected at kcos...kpub and kals taf sites. Slight
possibility of some ground fog developing at or near the kals
terminal this morning through about 14z or so...but not high enough
confidence to put in the taf at this time. Same thing could happen
again tonight 08-14z.

Other concern today will be for some isolated rain or snow showers
or thunderstorms...mainly along the Continental Divide...and mainly
over the Central Mountain portion of The Divide...during the late
afternoon and early evening hours. Local MVFR/IFR/LIFR conditions
will be possible with that activity.


Pub watches/warnings/advisories...
frost advisory until 8 am MDT this morning for coz069>071.

Frost advisory from 2 am to 8 am MDT Wednesday for coz069>071.



Short term...lw
long term...mozley

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