Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 101722

Area Forecast Discussion
National Weather Service Pueblo CO
1022 AM MST Sat Dec 10 2016

.SHORT TERM...(Today and tonight)
Issued at 457 AM MST Sat Dec 10 2016

...Strong winds mountains with Heavy snow and Blowing snow central
mountains this afternoon through tonight...

Upper jet is sagging southward across the Pacific NW/Rocky Mtn
region as the next Pacific trof drops southeastward and moves across
the northern U.S. Rockies later tonight.  This will shift the 110-
120 kt upper jet southward over CO by late tonight.  Quite a bit of
precipitation in area radars out west across CA/Nrn NV/Nrn UT...and
this will be spreading in the Sawatch and Mosquito ranges this
afternoon as deeper moisture spreads in. Favorable
orographics...along with strong higher elevation winds has prompted
an upgrade from a winter storm watch to a winter storm warning for
the central mountain areas...with advisories spreading into the
adjacent lower elevations down to 9000-10000 feet including the LXV
area. Getting amounts of 8-14 inches through 12z...with additional
amounts expected into early Sunday which will bring totals into the
12+ range for most of the higher elevations north of Cottonwood
pass. Lower elevations of central Lake county should see solid
advisory amounts in the 4 to 8" range.  With considerable blowing snow conditions will become hazardous tonight across
the Sawatch and Mosquito ranges.

For the southeast mountains...potential for strong to near damaging
wind gusts will be the primary concern from this afternoon through
tonight.  Best reverse shear occurs from this afternoon through
early evening...however it appears we lack a Mtn top inversion to
help transport that momentum down into the lower elevations. There
is always a chance that a wave induced critical later could
develop...and model cross-sections off the local 4 KM WRF suggest
this could occur.  However...the HRRR run is less aggressive and
keeps wind gusts below high wind thresholds...suggesting the lack of
a reflecting mechanism will be the overwhelming factor. After
03z...winds go pretty quickly forward shear as upper jet moves in.
Given WRF`s propensity to overdo winds...have leaned more towards
the HRRR for now.  Will have to watch the trends in the 12z runs and
latest mesonet observations and see how this pans out.

Otherwise...temperatures today should warm nicely over yesterday
with most areas warming into the upper 50s to mid 60s across the
plains. There may still be a cool pocket across Prowers and Kiowa
counties today where winds will stay south easterly...but even here
expect temperatures to moderate into the 50s.

Lee trof tonight should keep lower eastern slopes of the southeast
mountains on the mild side.  Winds spread down into the lower
elevations as the upper trof cross the mountains towards
morning...but given the strong forward shear...wind profile doesn`t
look as conducive for a mtn wave wind storm.  Any potential for high
winds will be over the peaks and through the gaps towards morning.
Will keep winds just below high wind thresholds for now.
Meanwhile...snow will spread southward into the southwest mountains
and portions of the Sangre De Cristo mountains towards morning. Snow
amounts should stay sub advisory. -KT

.LONG TERM...(Sunday through Friday)
Issued at 457 AM MST Sat Dec 10 2016

.Sunday and Monday...Disturbance moves east of the region with
drier air aloft moving into the area. Snow over the Continental
Divide region will decrease by midday Sunday with only periods of
light snow continuing through Sunday afternoon for the Sawatch
Range. Flow aloft remains brisk during the day with gusty winds
mostly over and near the mountains. On Monday, a cold front will
start moving southward over the eastern plains during the
afternoon. The core of the cold air remains well to the north of
the area. Grids currently have frontal passage during the
afternoon on Monday which will allow for some warming ahead of the

.Tuesday and Wednesday...Next disturbance moves into the region
with northwest flow aloft. Currently model consensus has most of
the moisture with this system staying over the northern half of
Colorado. The best chances for precipitation in our CWA will be
over the mountains of Lake and Chaffee Counties, and the
northwest flow aloft is not very favorable for snow in the eastern
San Juan Mountains. Further east, shallow cold air mass will move
into the eastern plains resulting in some cooler weather,
especially Wednesday. Not much moisture is expected on the plains
and eastern mountains as the upslope airmass will be shallow and
there will be no forcing aloft.

.Thursday and Friday...Model consensus is to have a trough dig
into the Great Basin around Friday with a disturbance moving into
the state by the end of the week. Some moisture will move into the
mountains on Thursday with snow mainly over the Continental
Divide region. On Friday, the amount of moisture increases with
increasing snowfall over the mountains. With the models indicating
southwest flow aloft, the eastern San Juans will have better
chances for more significant snowfall. Further east, pattern does
not look favorable for much precipitation. Any upslope airmass
will be shallow, and a lee trough could develop on Friday as the
disturbance approaches from the southwest. --PGW--


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1020 AM MST Sat Dec 10 2016

VFR conditions through the next 24 hours at all three terminals
with mid and high clouds spreading across the region. Winds will
be breezy this afternoon with gusts 20 to 25 kts expected. Strong
jet energy will move across Colorado tonight. Added LLWS to KPUB
based on model guidance, with the most prone time period from
04-14z tonight.  Mozley


Winter Weather Advisory from 2 PM this afternoon to 11 AM MST
Sunday for COZ059-061.

Winter Storm Warning from 2 PM this afternoon to 11 AM MST
Sunday for COZ058-060.



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