Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 230531
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1131 PM MDT Wed Mar 22 2017

.UPDATE...
Issued at 604 PM MDT Wed Mar 22 2017

Updated to cancel Red Flag Warning that was in effect for today
for Huerfano and Las Animas counties. Relative humidities in
Huerfano and Las Animas counties has risen above 15 percent and
therefore the warning is no longer needed. However, a Red Flag
Warning remains in effect for Thursday for the I-25 corridor and
all of the southeast Colorado plains.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 304 PM MDT Wed Mar 22 2017

...Snow Returns to the Divide...High Fire Danger Returns to the
Plains...Thunderstorms Possible...

Weather pattern will be in transition over the next 24 hours.
Developing upper low off the coast of California is making slow but
steady progress eastward this afternoon.  Models accelerate the
storm and move it eastward over the Great Basin by 6 am Thursday and
into western Colorado by 6 pm.  As it does so, snow, fire danger and
the potential for a few thunderstorms will ramp up across southern
Colorado.

For tonight, Red Flag conditions are occurring around the Trinidad
area this afternoon.  Expect those to continue for a few more hours.
So, the Red Flag Warning down there will continue for this evening.

As for precipitation, not much going on tonight.  There will be a
few spotty showers possible along the Continental Divide but little
if any snow accumulation is expected with those.

Thursday is when things start ramping up.  Snow should increase
along the Continental Divide during the morning hours, with showers
becoming widespread.  Widespread showers will then continue through
the afternoon and start to spread to the higher elevations of the
eastern mountains.  The high valleys in between could see a few
showers but coverage should be pretty spotty and amounts pretty
light.  The plains should generally remain dry Thursday.

There will be a slight chance of thunderstorms across the area
Thursday afternoon.  The best chance will be over the mountains,
closer to the approaching low.  However, the far eastern plains,
along the Kansas Border, near the dryline will also see a slight
chance of storms late in the day.  The Storm Prediction Center has
this area in a marginal to slight risk of severe weather if
storms can develop.

Fire Danger will be high across all of the plains Thursday
afternoon.  Winds, humidity and fuels will meet criteria on a
widespread basis starting late tomorrow morning and continuing into
the evening.  Gusts to 40 mph, humidities down to at least 10
percent and dry fuels will result in the potential for extreme fire
behavior.  Burning or any other activity that could accidentally
spark a wildfire should be postponed.

.LONG TERM...(Thursday night through Wednesday)
Issued at 304 PM MDT Wed Mar 22 2017

...high winds, snow and rain expected through Friday...

A very potent storm system is forecast to move across Colorado
Thursday night and Friday. The main forecast concerns will be the
very strong winds across the Plains, snow over the mountains and
into the Palmer Divide, and chance for severe weather out near the
Kansas border. Active weather will continue into the middle of
next week, however, there are slight differences in the model
solutions and ensemble members.

Thursday night and Friday...a strong upper level storm system is
forecast to move across northern New Mexico and into Western
Kansas. Expect snow to move into the Continental Divide Thursday
evening and spread into the Eastern Mountains through the
overnight hours.

A surface dryline is forecast to develop out near the Kansas
border late Thursday afternoon. The NAM and NAM 3km develop a
line of thunderstorms along the dryline and spread it east into
western Kansas during the evening hours. The main question will be
how far west convection develops. Modest dewpoints in the 40s
ahead of the dryline will lead to CAPE values around 1000 j/kg.
Shear looks good which should allow storms to rotate in the mid
levels with the primary threat being large hail and strong winds.
Again, severe weather will depend on where the dryline sets up.

The surface cold front is forecast to quickly drop south over the
Palmer Divide and down the I-25 corridor late Thursday night.
Northerly winds 35 to 45 with gusts in excess of 65 mph are likely
late Thursday night into Friday morning, before spreading east
across the Plains Friday afternoon. Hazardous travel conditions
are expected on east to west highways. In addition, downed power
lines may lead to power outages. Tree damage is also possible.
Expect winds to weaken from west to east Friday afternoon and
clear into Kansas by the evening hours.

The other main concern will be the potential for heavy snowfall
over the Palmer Divide. Model guidance suggests 6 to 10 inches
with locally higher amounts possible. This snowfall combined with
the strong winds will produce very hazardous conditions over
northern El Paso County. Near zero visibilities on area roadways
and heavy wet snow may cause tree damage on trees where leaves are
already occurring. The morning commute on Friday will be heavily
impacted.

Elsewhere across the Plains, snow levels look to remain above 6000
feet through the event. Lower elevations will likely see mostly
rain, with perhaps a few snow flakes mixed in as the upper system
moves off to the east.

Saturday...a quick moving ridge of high pressure will move across
Colorado on Saturday with quiet conditions throughout the days.
Temperatures will be 60s for highs.

Sunday into Wednesday...another upper storm system is forecast to
move across the state Sunday into Monday with another round of
rain and snowfall for the Plains. Another storm is forecast to
move across the Desert Southwest by mid week which may lead to
another period of rain and snow.  Mozley

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1125 PM MDT Wed Mar 22 2017

VFR conditions can be expected at the terminal forecast sites
tonight through at least late afternoon on Thu. Thu morning, south
to southwest winds will increase across all of southern CO, with
gusts in the afternoon hours of 30 to 40 kts. KALS could see some
showers move into the VCNTY mainly after 21Z, with ceilings
lowering, but at this time it looks like they will remain VFR thru
the evening. In the evening a cold front will move south thru ern
CO and winds will become northerly at KPUB and KCOS and will
become quite strong by around 06Z with gusts Thu night and into
Fri morning of 45 to 55 kts, and maybe evening higher at times.
Showers are also expected to move into KCOS and KPUB, mainly after
03Z Fri.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM to 8 PM MDT Thursday for COZ226>237.

High Wind Watch from late Thursday night through Friday
afternoon for COZ084>089-093>099.

Winter Storm Watch from Thursday afternoon through Friday
afternoon for COZ073-075-080-082.

Winter Storm Watch from Thursday evening through Friday
afternoon for COZ081-084.

&&

$$

UPDATE...28
SHORT TERM...LW
LONG TERM...MOZLEY
AVIATION...28


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