Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 151008

Area Forecast Discussion
National Weather Service Pueblo CO
408 AM MDT Tue Aug 15 2017

.SHORT TERM...(Today and tonight)
Issued at 408 AM MDT Tue Aug 15 2017

...Best Storm Chances over the Plains Today...

Upper level trough visible in satellite over Nevada and Utah this
morning.  This upper trough will move into western Colorado by this
afternoon and then over the I25 corridor by Wednesday morning.  The
upper trough will act as a trigger to storm development across the
plains in the afternoon and overnight.  Models have the best
development this afternoon over the far eastern plains, generally
along and east of a north-south line through La Junta.  Out there,
storms have the potential to become strong to severe during the
afternoon.  Shear is not real impressive, though, so only marginally
severe storms are expected with hail up to an inch in diameter and
wind gusts to 60 mph possible.  Farther west, it appears that some
drier air may advect in from the southwest, ahead of the trough this
morning, limiting the overall thunderstorm potential during the
afternoon. Satellite derived Total Precipitable Water Values across
Arizona, southeast Utah and southwest Colorado are currently only
running 30-70 percent of average.  This air will advect eastward
across the mountains this morning, really taking down the amount of
moisture available for convection.  So, it might be a bit of a down
day for convection across the mountains and high valleys today with
most of the activity out across the plains.  That`s great for the
burn scars.  However, it will be a little busy again out across the
far eastern plains in the afternoon.

Tonight, the upper trough axis will move from western Colorado
toward the I25 corridor.  This timing will allow for the development
of nocturnal convection.  Right now, it appears the main forcing for
the nocturnal convection will occur primarily north of our area, up
across northeast Colorado and then into southwest Nebraska and
northwest Kansas.  This is where the Storm Prediction Center
currently has the slight risk area for severe weather.  This looks
good based on the location of the primary upper forcing and surface
moisture convergence associated with the low level jet.  NAM12,
GFS20 and available hi res model data keeps most of the convection
north of southern Colorado overnight but it could be close.  Some
runs clip El Paso County late in the evening and possibly bring some
activity across Kiowa County overnight as well.  Will have to keep
an eye out for this potential activity.

.LONG TERM...(Wednesday through Monday)
Issued at 408 AM MDT Tue Aug 15 2017

Wednesday through Friday...Models indicate an upper trough crossing
the region on Wed, then a couple of minor disturbances passing by on
Thu and on Fri. This will provide for a weak easterly llvl wind flow
through at least Thu, with isolated convection forecast across the
eastern plains. Look for high temps in the 70s to around 80F for the
high valleys, and mid 70s to upper 80s for the eastern plains.

Saturday through Monday...An upper low pressure system begins to
develop over CA Fri night, and strengthens over the weekend. The
upper flow will become more west to southwest, drawing moisture up
into the western half of the state as well as producing warming
downslope winds for the eastern plains. Expect convection to be tied
more to the higher terrain over the weekend and into Mon, with just
isolated activity for the east. Max temps are forecast to be in the
70s to around 80F for the high valleys, and 80s to lower 90s for the
eastern plains. Moore


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 408 AM MDT Tue Aug 15 2017

An upper trough visible in satellite over Nevada and Utah at this
time will move into western Colorado this afternoon and then over
the I25 corridor by Wednesday morning.  This disturbance will
trigger convection across the far eastern plains this afternoon,
primarily along and east of a north-south line through the KLHX.
Farther west, dry air from the southwest will advect in ahead of the
disturbance, reducing the number of storms today from the I-25
corridor westward.  Tonight, nocturnal storm development will be
possible across the plains, but primarily along and north of the
Palmer Divide.  It is possible that nocturnal storms could develop
across El Paso and Kiowa Counties but most model runs keep activity
north of these areas overnight.  It looks like dry enough air will
make it into the KALS and KPUB terminals for no storms today.  There
is a small chance that KCOS could still see a late day storm so VCTS
will remain in the TAF for that site after 22Z.  Otherwise,
generally VFR across the flight area next 24 hours except in areas
of precipitation where local MVFR, IFR and LIFR conditions will be




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