Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 221740

Area Forecast Discussion
National Weather Service Pueblo CO
1140 AM MDT Thu Mar 22 2018

.SHORT TERM...(Today and tonight)
Issued at 424 AM MDT Thu Mar 22 2018

...Snow ramps up for the Continental Divide tonight with strong
winds for the southern mountains...

Upper trof will approach the west coast today and translate eastward
into southwest CO tonight sending 100+ kt upper jet into western CO
by early Friday morning.  Ahead of the system today, another
relatively dry day is expected side from some isolated afternoon
snow showers along the Continental Divide. Snow levels will remain
quite high however, generally 10.5kft and above.  Winds will start
to increase across the mountains and southern I-25 corridor, but
relative humidity values for these areas stay above the 15% critical no fire weather highlights look necessary.
Temperatures will warm well into the 70s across the plains 50s and
60s valleys and 30s and 40s mountains.

Tonight...snow will ramp up along the Continental Divide after 03z
as the upper trof approaches.  Southwest orographic flow will favor
the eastern San Juan mountains for the heaviest accumulations,
particularly after 06z.  Snow levels stay around 10kft before
dropping towards 9kft towards morning.  Thus, snowfall amounts of 1
to 6 inches will be possible across the higher Sawatch Range and the
Eastern San Juan mountains by early Friday morning with additional
moderate to heavy snow expected through Friday (see below). Areas of
blowing snow will be likely across the higher peaks after 06z as

Meanwhile, it should be a warm night across the plains as lee side
surface low deepens towards morning.  High res model soundings/cross-
sections suggest a brief period of near high wind criteria will be
possible in the lee of the southern Sangre De Cristo
mountains/southern I-25 corridor late tonight.  Mtn top stable layer
briefly develops between the 09z-12z timeframe before the upper jet
translates in with strong forward shear developing after that. For
now think winds are more likely to stay just under high wind
criteria and given the brief nature of the event, will not issue a
high wind watch at this time.  If it occurs, area most likely to see
these conditions would be western Huerfano county.  Will let later
shifts monitor this and issue any wind highlights as needed. -KT

.LONG TERM...(Friday through Wednesday)
Issued at 424 AM MDT Thu Mar 22 2018

Friday...Strong southwest flow aloft will be in place across the
Four Corners and the state, as an upper shortwave streams across the
northern Rockies. This will bring moderate to at times heavy snow
and blowing snow to the higher terrain late Thu night through Fri,
with the focus areas being the central mts and the southwest mts.
Total new snow accumulations of 5 to 8 inches, with localized
amounts of up to 16 inches, will be possible by Fri evening. At the
same time, the strong downslope winds will produce very warm and dry
conditions for the eastern plains through the afternoon hours, and
decided to upgrade the Fire Weather Watch to a Red Flag Warning for
all of the plains. Any fires that do start will be quick to
spread, and care should be taken with all outdoor activities. Look
for high temps in the mid 50s to mid 60s for the high valleys,
and 70s to lower 80s for the plains. A cold front will drop south
across the eastern plains Fri night, swinging sfc winds to a more
north to northeast direction late.

Saturday and Sunday...A large upper trough just off the West Coast
early Sat will edge onshore through Sun. This will keep the Great
Basin and Rocky Mt region under brisk southwest flow over the
weekend and keeping the temps elevated. It looks as if it will dry
out across the forecast area for Sat, but isolated to scattered snow
showers return to the Continental Divide by Sun. As for fire weather
concerns, the late Fri night cold front will usher in higher
dewpoints for the far eastern plains, which should keep RH levels
above critical criteria out east on Sat. The one questionable area
will be along the I-25 corridor, but since winds are forecast to be
borderline as well, will not go with any fire weather highlight on
Sat at this time. On Sun temps warm back up, RH levels drop once
again, and there looks to be a more uniform southwest wind component
across all of the plains so Sun looks like another critical day.
Expect highs in the upper 50s to lower 60s for the high valleys, and
mid 60s to lower 70s for the plains on Sat, then 50s for the high
valleys and upper 60s to around 80F for the plains on Sun .

Monday through Wednesday...EC and GFS models still tend to agree
that a closed upper low drops south across the Great Basin on Mon,
reaches AZ on Tue, then slowly tracks east across NM on Wed. Mon
will likely be another very warm day, but pcpn chances start to
increase across all of the forecast area starting Mon night and
lasts through Wed, as well as increased cloud cover and much
cooler temps for Tue and Wed. However, pcpn amounts and location
are still a big question as model output has been a bit muddled.
Look for maximum temps in the 50s for the high valleys and upper
50s to mid 70s for the plains on Mon, then 40s to lower 50s for
most areas both Tue and Wed. Moore


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1131 AM MDT Thu Mar 22 2018

VFR conditions at all taf sites the next 24 hours with very windy
conditions developing late Fri morning. At KALS, S-SW winds will
increase this afternoon, with gusts over 20 kts until 02z. After a
brief lull overnight, SW winds will increase Fri morning, and
gusts to 25 kts will develop by sunrise, then 35 kts by late
morning. A few gusts to 45 kts will be possible Fri afternoon. At
KCOS and KPUB, S-SE winds will become briefly gusty this
afternoon, then diminish overnight. W-SW winds then begin to
increase early Fri morning, with gusts 25-30 kts by 16z-17z. Gusts
over 40 kts will be likely Fri afternoon. Over the mountains, a
few snow showers will develop along the Continental Divide this
afternoon, with steadier and heavier snow bringing IFR cigs/vis
overnight and Friday. Eastern mountains/interior valleys will see
-shsn develop tonight and Friday, with higher peaks occasionally


Red Flag Warning from 11 AM to 7 PM MDT Friday for COZ226>237.

Winter Weather Advisory from 9 PM this evening to 9 PM MDT
Friday for COZ060-068.



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