Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 271756

Area Forecast Discussion
National Weather Service Pueblo CO
1156 AM MDT Mon Mar 27 2017

.SHORT TERM...(This afternoon through Tuesday)
Issued at 1148 AM MDT Mon Mar 27 2017

Package update coming out shortly to hoist winter weather
advisories for the Continental Divide and Winter Storm Watches for
the southeast mountains and the Palmer Divide and Raton Ridge.
Still some questions on snow levels...with soundings suggesting
snow won`t drop into the Palmer Divide and Raton regions until
after 06z Wed...possibly until 12z. If so...its possible these
areas may end up in the advisory range for snow accumulations...but
just a couple degrees cooler a little quicker Tuesday evening and
amounts could end up near a foot for these lower elevation regions.
Thus will include these areas in the Watch for now. Still looks
like focus for the heavier snow 1-2`+ will be across the Wets and
Sangre De Cristo Mountains Tuesday night through Wednesday. Update
coming out shortly.

.LONG TERM...(Tuesday through Sunday)
Issued at 410 AM MDT Mon Mar 27 2017

...High Impact Storm Likely Tuesday Night and into Wednesday...

...Another High Impact Event Possible Friday into Saturday...

A couple of impressive storm systems will affect our region
during this forecast period. These storms show promise of bringing
significant and beneficial precipitation to the region. However,
they both have the potential to bring high impact weather to the
region due to the heavy snow potential each storm will have. The
main concern at this time is: At what elevation will the
significant snow begin to accumulate?


A large 500 mb closed low is forecast by all guidance to be
located over the 4 corners region at 12Z Tuesday (6 AM Tuesday
morning). This cyclone is forecast to move slowly to the east and
will be located roughly along the CO/NM border south of Alamosa by
00Z Wednesday (6 pm Tuesday evening).

Showery precipitation  will likely be ongoing across all of the
higher terrain Tuesday morning. Over the far eastern plains, a
band of more significant rain will likely  be along and to the
east of the CO and KS border. Most of the eastern plains of se CO
will likely be dry slotted and little if any precip is expected in
the morning.

As the afternoon progresses and the low moves east, a more
significant easterly component develops over the plains. This system
is fairly stacked and the upslope will be deep. Showery precip will
increase over all of the plains and interior mtns. The main area
of heavy precip, however, will develop during the afternoon along
the mtns/plains interface as the saturated, moist upslope flow
impinges the mtns. the rain/snow line will likely be quite high
early in the day....roughly 8000 ft...but will decrease as the
lower levels saturate and web bulb zero values decrease. by early
evening the rain/snow line could be down as low as ~6000 feet.

Some strong thunder is not out of the question across the region on
Tuesday. Some guidance is showing CAPE approaching 1000 J/KG with
most of the higher values along the I-25 corridor sotu of Pueblo.
We will have to keep a close eye on the numerous burn scars
across the region Tuesday afternoon. A severe storm is not out of
the question.

Tuesday night...

This is when the heaviest precip will be falling along the
mtns/plains interface as the best upslope will be in place along
with the deformation zone being along the the greater I-25 corridor
region. Soundings indicate that the rain/snow line will lower down
to possibly 5000 feet, and this will bring snow into the populated
areas along the I-25 corridor. Given such rather strong forcing,
even Pueblo may see some accumulating snow. Without saying, the
Pikes Peak region will be highly impacted with this storm along with
the remainder of the cities/towns along the I-25 corridor. In
addition, winds will ramp up with this storm (although they are note
expected to be as strong as last Fridays storm), with winds gusting
to 30 to 35 mph across El Paso and Pueblo counties by early
Wednesday morning. Travel across most if not all of the I-25
corridor will be tedious at best Wednesday morning.


The brunt of the storm will start to translate south and east as the
day progresses, with areas along the southern mtns and along the
CO/NM border seeing the worst of the storm. knowing where the
rain/snow line is going to be is difficult, as soundings indicate
snow may get as far as Springfield and La Junta for a period
during the day on Wednesday. I expect the Spanish Peak/Raton mesa
areas above will have the potential for some decent accumulating
snow with this event.

The Wets and Sangres will have the potential to see large
accumulations of heavy snow with this event, with 2 to 3 feet
amounts common.

The lower plains should see some good rains with this event, and all
areas will have the potential to see at least 0.50" or more of
liquid with this storm.

By Wed evening, most of the activity will likely be south and east
of a line from KLHX to KTAD, and this activity will continue to
move to the southeast as the evening progresses.


Short wave ridge moves over the region and it should be
predominantly dry. Max temps this day will be tricky because they
will be dependent on how much snow falls across the region.

Friday and Saturday...

Another strong closed low moves across the area. Precip will move
into the mtns by Friday morning and onto the plains by evening.
Heavy precip is likely and once again the rain/snow line will be
problematic. There is some discrepancies between the models as
the  EC shows a more W to E track just south of the CO/NM border
while the GFS tracks it farther southeast across c NM. I should
note that the GFS was much farther south with this system
yesterday at this time, so the GFS is coming more in line with the
euro model. This second storm will have the potential to be
another high impact event.


Two significant storms are being forecast by the guidance for our
area. The simulations are in pretty good agreement with each
other so confidence is higher than normal that the events will
occur. The main concern at this time is the rain/snow line as
these events. These storms are predicted to be colder than last
Fridays storm so the snow/rain line will reach farther east onto
the plains which will in turn affect more of the population
centers in our region.

Any heavy wet snow at lower elevations will have the potential to
cause tree damage as many trees have greened up.

In addition, last Fridays wind storm cause widespread roof damage to
many homes. Any rain/snow will have the potential to cause
additional damage to these homes.

The wind with Tuesday night/Wednesday event will be blustery, but
winds are not forecast to be damaging.

Winter Weather Watches/Advisories will likely be issued for parts of
the region later on today.

Please keep abreast to the weather forecast as we get closer to the
event(s). /Hodanish


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1148 AM MDT Mon Mar 27 2017

VFR conditions expected today with a round of showers moving off
the mountains and possibly affecting the terminals in the roughly
00z-06z. Cigs will mostly likely remain VFR with -SHRA should
these impact the terminals. There is a slim chance that some IFR
cigs could briefly develop late tonight for KCOS with southeast
winds upsloping on the Palmer...however uncertainty is too high to
put this in a prevailing group. Otherwise...another round of
heavier rain will spread in Tuesday afternoon for all three
terminals...just beyond the TAF valid period. Rain will change to
snow late Tuesday night at KCOS and KALS with IFR conditions
likely. -KT


Winter Storm Watch from late Tuesday night through Wednesday
afternoon for COZ084-087-088.

Winter Storm Watch from Tuesday evening through Wednesday
afternoon for COZ072-074-079-081.

Winter Weather Advisory from 6 PM this evening to noon MDT
Wednesday for COZ058-060-066-068.

Winter Storm Watch from Tuesday afternoon through Wednesday
afternoon for COZ073-075-080-082.



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