Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 271139

Area Forecast Discussion
National Weather Service Pueblo CO
439 AM MST Mon Jan 27 2020

.SHORT TERM...(Today and tonight)
Issued at 342 AM MST Mon Jan 27 2020

Currently, latest satellite imagery and upper-air analysis indicates
a trough axis extending from Idaho into Arizona. Clouds associated
with this trough are beginning to move over the Continental Divide
from the west and southwest. In general, observations show
relatively light winds across the region with temperatures in the
20s across the plains and teens in the high valleys. With an
inversion in place, a few spots on the lee side of the eastern
mountains remain in the 30s at this hour.

The aforementioned trough is expected to propagate through Colorado
and into the Southern High Plains by Tuesday morning. As it does,
much of the area will have at least a chance to see some
precipitation. Latest guidance indicates that the trough will remain
as a progressive open wave, which means it will likely move through
quickly and tends to favor lower precipitation amounts. Many of the
mountains should see some snow, with generally light accumulations
of an inch or two. The main exception will be the southern Sangre de
Cristos, where 2 to 5 inches, with locally higher amounts are
possible. The plains should see mostly rain this afternoon before
mixing with snow overnight. As of now, the snow accumulations are
expected to be less than an inch in these areas.

Now for the tricky part of the forecast, the last several HRRR runs
have consistently shown some convective snow bands moving along the
Palmer Divide late this afternoon and evening, which soundings do
support this possibility. However, it does seem overdone with the
intensity and QPF/snow amounts. Based on this, have decided to
include a broader area of 2 inch snow accumulations in the forecast
for the Palmer Divide area. If a convective band of snow does
develop, some localized amounts of 4 inches or more are not out of
the question.

Afternoon highs should be near 50 across the plains, and 30s to 40s
in the high valleys ahead of the system, while tonight lows are
expected to dip down into the 20s across the plains and single
digits in the high valleys.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 AM MST Mon Jan 27 2020

A brief reprieve is expected for Tuesday as shortwave ridging
translates in overhead bringing dry weather to southern Colorado.
Temperatures will remain relatively cool on the back side of the
exiting system, but overall readings will still be at or slightly
above climatological normals.

The next storm system will be taking shape across the western
U.S. Tuesday night and Wednesday...though models have diverged
some over the exact track and timing of the system`s
intensification as it evolves into a closed low across the Desert
Southwest. EC is the farthest west and south with the track as it
drops it through NV/UT and into southwest AZ by Wednesday evening.
GFS has reverted to a farther east and less closed off solution,
dropping it across AZ by the same time frame. NAM12 and Canadian
appear in between these two camps. GFS ensembles and mean seem
pretty close to the operational GFS. Have leaned towards model
blends for now given the continued disparity. Overall, looks like
the northern stream portion of the trough will have the greatest
influence over southern CO weather as the majority of the lift
with the southern extension of the storm appears to track too far
south. So sensible weather-wise, expect snow to spread back into
the mountains late Tuesday night into Wednesday, with rain and
snow showers spreading into the I-25 corridor and adjacent plains
Wednesday afternoon and night as a cold front moves through. Still
looks like a light event for southern CO given current storm
track/evolution, but the details are still prone to change at this
point. Current forecast is a broad brush for now.

Thursday will remain cool and unsettled with trailing energy
dropping down in northwest flow. Isolated to scattered snow
showers will be possible with the best chance for snow across the
central mountains.

A drying and warming trend sets in for Friday through the weekend
with temperatures possibly climbing to near 70 across the plains
by Sunday. -KT


.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 342 AM MST Mon Jan 27 2020

At KALS, VFR conditions are expected through about midday. Ceilings
are then anticipated to reach MVFR conditions for a few hours this
afternoon as a system brings some passing showers to the area. Winds
stay relatively light, generally less than 15 kts.

At KCOS and KPUB, VFR conditions are expected to prevail until late
afternoon at which time MVFR conditions with showers are anticipated
for a few hours. VFR conditions are expected to return late this
evening. Winds are anticipated to become gusty from the north at 15
to 20 kts by this evening and persist overnight, especially for




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