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Area forecast discussion
National Weather Service Pueblo Colorado
329 PM MDT Sat Oct 19 2019

Short term...(this evening through sunday)
issued at 328 PM MDT Sat Oct 19 2019

Currently, analysis of GOES water vapor imagery reveals a compact
but potent shortwave trough rolling across central Idaho, with an
associated westerly just pushing into the Great Basin and western
Colorado. There is no precip ongoing over southern Colorado, and
skies are mainly clear. Winds are gusting out of the west as high as
40 knots across the Continental Divide, and up to 30 knots across
the eastern mountains and valleys with gusty winds bleeding into the
I-25 corridor. The gusty winds and low humidities are causing red
flag conditions across the eastern mountains and portions of the I-
25 corridor. Temperatures are in the 60s across the eastern plains
and I-25 corridor, and 40s to 50s in the high valleys.

Tonight through tomorrow, the aforementioned shortwave will continue
east across the northern rockies this evening and into the northern
High Plains tomorrow. The associated jet will round its base over
Colorado, yielding strong westerly winds over the forecast area.
Favorable orographics and synoptic scale lift, along with near-
normal tpw will result in the development of snow showers over the
Continental Divide lasting from around midnight through noon on
Sunday. The central mountains will see the greatest snow totals,
with 4-8 inches expected, including 2-5 inches in Leadville.
Therefore, the Winter Weather Advisory remains in effect during that
same period. Areas further south along the Continental Divide should
see around 1-3 inches, while higher elevations in the eastern
mountains are expected to receive less than 1 inch total.

The other main story with this weather system will be the strong
winds and critical fire weather conditions. Downsloping westerly
flow and a drying airmass will result in deep vertical mixing during
the afternoon on Sunday. Rhs will plummet well below 15% during the
day for areas east of the Continental Divide. 40-50 knot winds are
forecast at around 700 mb, so winds gusting to 50 knots at the
surface is certainly possible, primarily over the eastern mountains
and into the I-25 corridor. Wind gusts to 40 knots are forecast
across much of the forecast area. The gusty winds will combine with
the low relative humidity to yield critical fire weather conditions for all of the
forecast area minus the Continental Divide, where relative humidity should be
slightly above critical thresholds. The red flag warning remains in
effect from 11 am through 8 PM on Sunday.

Overnight lows will be quite mild across southern Colorado this
evening, with highs in the mid to upper 30s across the plains, and
20s in the high valleys. On Sunday, highs will be slightly below
normal, with temperatures in the low 60s across the plains, and 40s
in the high valleys.

Long term...(sunday night through saturday)
issued at 328 PM MDT Sat Oct 19 2019

Fairly strong northwest flow aloft will be found over the area Sun
night through Tue, with some snow showers being possible over lake
and Chaffee counties, especially Sun night through Mon evening. The
rest of the area looks dry during this time. Temps acrs southern Colorado
will be below average on Mon, with highs in the 50s to lower 60s
east of the eastern mtns, and in the mid 40s to lower 50s in the
high valleys. Temps on Tue will be warmer, with 60s acrs southeast
co, and in the 50s to around 60 in the high valleys.

One concern for Mon is the potential for areas of critical fire
weather conditions. Breezy to windy northwest winds are expected
over much of the area Mon afternoon, and relative humidity values look like they
will generally drop below 20 percent in portions of the San Luis
valley and the southeast plains, mainly south of the Arkansas River
valley. The only area that the models are fairly consistent in
showing conditions that meet red flag criteria, is over Huerfano and
Las Animas counties. Thus, for now will issue a Fire Weather Watch
for those fire weather zones (229, 230 and 233). However,
conditions will probably be marginal for fire weather concerns over
southern Pueblo, Baca, and portions of Otero counties, and the
southern half of the San Luis valley, and it is possible that a fire
weather highlight may be needed for these areas as well, depending
on how future model runs change.

Things start to change on Wed, as an upper trof from the northern
rockies digs into co, bringing a front and chances for precip late
in the day. Temps on Wed look like they will be only slightly below
average. The upper trof sinks south over Colorado thru Thu, and finally
exits the area Thu night. There are only some minor differences
between the GFS and ec with the timing of this system. If things
pan out the way the models currently show, widespread precip can be
expected Wed night and Thu, along with much cooler temps on Thu. The
mtns will see snow, while Wed night/Thu morning, chances for snow
would mostly be above above 4500 feet. Snow level rise a bit Thu
afternoon, but some of the higher elevations in El Paso County could
see chances for snow thru the day Thu. However, at this time, snow
amounts generally do not look significant. Low temps Thu night/Fri
morning should be quite cool.

With the upper trof exiting the area by Fri morning, dry weather
will return for Fri and Sat. Temps will still be below average on
Fri, but should warm to near average on Sat.

&&

Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 328 PM MDT Sat Oct 19 2019

VFR and dry conditions are expected at the three taf sites (kals,
kcos, kpub) over the next 24 hours. All three sites will see winds
increase out of the northwest tomorrow morning, gusting 30-40 knots
or stronger by mid morning. Winds will remain gusty through the
afternoon, weakening by early evening.

&&

Pub watches/warnings/advisories...
red flag warning from 11 am to 8 PM MDT Sunday for coz222-
224>237.

Red flag warning until 8 PM MDT this evening for coz220>222-
224>230.

Winter Weather Advisory from midnight tonight to noon MDT Sunday
for coz058>060.

Fire Weather Watch from Monday afternoon through Monday evening
for coz229-230-233.

&&

$$

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