Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 181049

Area Forecast Discussion
National Weather Service Pueblo CO
449 AM MDT Sun Mar 18 2018

.SHORT TERM...(Today and tonight)
Issued at 449 AM MDT Sun Mar 18 2018

...High impact weather ranging from snow to wind to high fire danger
next 24 hours across southern CO...

Upper low over the Great Basin is progged to shift eastward and
deepen across northern NM/southern CO by 00z today before quickly
moving eastward into northeast OK later tonight.  Starting to see
some lower clouds spread into the Eastern San Juans early this
morning but no snow as of yet and models look to hold the majority
of it off until after 15z.  Consequently, have delayed the onset of
the winter weather advisory for this area.

Meanwhile, lee side surface low will deepen this afternoon across
the southeast plains with strong southwest winds, warm temperatures
and low humidity values expected across the plains.  Strongest winds
will affect the southern and eastern tier of counties initially. By
afternoon there will be a period of strong winds across most of the
I-25 corridor as H7 front crosses the mountains. Virga will likely
aide in bringing gusts to around 40 to even 50 mph in some places
this afternoon. A little less certainty exists farther north across
El Paso county where gusts may hold off until later in the afternoon
and humidities are expected to quickly rise behind the front after
23-00z. Not quite getting the required 3 hour duration of critical
fire weather conditions, though there will be a brief period of
strong winds late this afternoon ahead of the front.

Snow will spread into the southeast mountains this afternoon then
into the Palmer Divide with a rain snow mix initially this evening,
changing over to all snow by 03z.  Models also show some instability
with this system which is always a wild card for snow amounts this
time of year.  The progressive nature of this storm however should
limit snowfall accumulations for most areas to advisory amounts.
Have added Northern El Paso county into an advisory for this evening
through the overnight hours, especially given the likelihood for
blowing snow overnight. Snow amounts will be highly variable with
anywhere from a Trace across the south to near 5 inches for the
northern portions where upslope will be maximized. Farther south in
Colorado Springs, only a trace of snow is expected.  For the plains
strong northerly winds tend to provide a downslope component towards
the Arkansas River valley and an upslope component for the northern
slopes of the Raton Ridge. Models still trying to resolve how far
south and west wrap around precipitation will spread.  Have
increased pops out from roughly La Junta eastward, however mixing
keeps temperatures above freezing for most of the night.  Could see
a late switch over towards morning but by then system will be
pulling eastward pretty fast which should limit accumulations
significantly to perhaps a trace of snow in spotty areas.

Other concern is potential for near high wind criteria this evening
with the northerly surge behind the cold front.  If timing of the
front were a little earlier in the day, would consider a high wind
watch. However given the later timing...think gusts in the evening
could approach 50-55 mph but should stay just shy of high wind
criteria. This is something later shifts will need to monitor
though.  If storm strengthens further as it ejects into the plains
then we could see stronger winds. -KT

.LONG TERM...(Monday through Saturday)
Issued at 449 AM MDT Sun Mar 18 2018

Monday-Monday night...Moderate northwest flow aloft progged across
the region as broad upper trough and vertically stacked low continue
to quickly translate east into the High Plains. Strong and gusty
north to northwest gradient winds of 25 to 45 mph across the
Southeast Plains early Monday morning, diminish through late morning
and afternoon. Latest models indicating some wrap around precipitation
across the far Southeast Plains early Monday morning, with a few
showers possible across the higher terrain Monday afternoon, as a
minor embedded wave translates through the northwest flow aloft.
Temperatures below seasonal levels in the 40s to lower 50s across
the Plains, combined with the wind, will lead to a blustery day
across Eastern Colorado Monday.

Tuesday-Wednesday...A warming and drying trend remains in the offing
as upper level ridging builds across the Rockies. Models do suggest
a few possible orographic showers Tuesday across the Central Mts,
though does not look to be much more than a few flurries. Temperatures
warm back to at and above seasonal levels through the period, with
highs on Wednesday in the mid 50s to mid 60s across the lower elevations
and mainly in the 40s and 50s across the higher terrain.

Thursday-Saturday...Will see increasing chances of precipitation
across the ContDvd Thursday and Friday, as more Pacific energy moves
across the West Coast and into the Rockies. The increasing westerly
flow will also help boost temperatures to well above seasonal levels
and lead to the potential for critical fire weather conditions
across the area both Thursday and Friday. Models differ on timing
and location of more energy moving across the area on Saturday,
though again looks the mainly bring precipitation chances to the
higher terrain.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 449 AM MDT Sun Mar 18 2018

Gusty southwest winds will spread into the terminals this afternoon
affecting KALS around 15-16z with gusts to around 25-30 kts through
the afternoon.  KPUB and KCOS will see southwest winds spread in
during the 18-21z window with gusts in the 25-30 kt range.  Winds
will shift out of the west towards 00z with gusts to 30-40 kts
possible.  Then a cold front will drop south of the Palmer Divide
bringing a sharp wind shift from the north and gusts to around 45
kt.  This will occur around 00z for KCOS and around 01z for KPUB.
Snow will spread into the Palmer Divide around 00z with a brief
round of -SHRASN after 03z...and -SHSN after 06z.  Strong north
winds should limit accumulations to around a Trace at KCOS.  KPUB
could see VCSH overnight but temperatures look too warm for any snow
accumulation.  Showers should pull east of the I-25 corridor by 12z
Mon. KALS could also see showers during the late this afternoon
through early evening hours though little to no accumulation is
expected. Brief MVFR cigs may occur at the terminals through tonight
with any showers but IFR and lower conditions should stay confined
to the Continental Divide and northern slopes of the Palmer ridge.


Red Flag Warning from noon today to 8 PM MDT this evening for

Winter Weather Advisory from 9 AM this morning to 9 AM MDT
Monday for COZ058-060.

Winter Weather Advisory from 9 AM this morning to 6 AM MDT
Monday for COZ068.

Winter Weather Advisory from 7 PM this evening to 6 AM MDT
Monday for COZ084.



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