Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 270545

Area Forecast Discussion
National Weather Service Pueblo CO
1145 PM MDT Fri May 26 2017

Issued at 816 PM MDT Fri May 26 2017

Severe Thunderstorm Watch for southeast Colorado and western
portions of east central Colorado allowed to expire. Activity
should be just about done for the night.


.SHORT TERM...(This evening through Saturday)
Issued at 354 PM MDT Fri May 26 2017

...Active severe weather pattern next couple days...

Moisture has been slow to recede across the southeast plains this
afternoon with dew points as of 20z in the mid-upper 40s.  Weak
disturbance evident in WV imagery is currently moving through
southwest CO and should provide at least some weak lift across the
area this afternoon through this evening.  Meanwhile...models
sharpen up the dry line along a line from KCOS to just east of KPUB
to Kim, CO by 21z.  Various high res models show 2 areas of isolated
thunderstorm initiation this along the dry line
across eastern Las Animas county...and another across Teller and El
Paso counties. Strength of storms today will be dependent on how
much moisture mixes out and various models differ with this. Dew
points which stay up in the mid to upper 40s will yield CAPE values
in the 1000-1500 j/kg range.  If they drop back into the 30s...then
CAPES sliver out aloft pretty quick.  0-6 KM shears in the 40-50 kt
range according to NAM favors potential for supercells with main
threat being large hail and damaging winds.  Although tornado threat
does not look terribly high...there could be a brief tornado if
rapid storm updrafts can stretch vorticity along boundaries.  For
now this looks like an outlier potential...but bears watching.

Activity shifts eastward into Kansas by 7PM with activity decreasing
across southeast CO. Another front drops through the plains
overnight with the potential for stratus to develop across portions
of the plains by Saturday morning.  This primes up the area for
another round of more widespread thunderstorms Thursday afternoon as
the western U.S upper trof finally moves across.  Looks like
convection should fire around 18z across the mountains.  Amount of
instability will be the main concern for thunderstorm strength on
Saturday but atmosphere will be strongly forced so suspect strong to
severe storms will be possible once again with best area for severe
being south of highway 50 and along the Raton Ridge. Deep layer
shears will be running around 50-60 kts...and although large hail
and damaging winds will be the primary isolated tornado
would be possible along the Raton Ridge where low level easterlies
maximize.  There is some concern that atmosphere will be capped at
least initially...farther to the east.  High res models suggest
convection evolves into an MCS which propagates eastward through the
evening.  Heavy rainfall on burn scars will be a concern as well.

.LONG TERM...(Saturday night through Friday)
Issued at 354 PM MDT Fri May 26 2017

Not many significant adjustments required from previous
meteorological thinking as unsettled conditions are still
anticipated during the longer term with main issues continuing to
be temperatures, pops/qpf, winds, and the potential for strong to
severe thunderstorms as well as locally heavy rainfall at times.

Longer range PV analysis, computer simulations and forecast model
soundings continue to suggest that upper disturbances interacting
with north-northeasterly surface surges/surface boundaries over
southern Colorado into later next week.

It still appears that the highest potential for more widespread
locally heavy rainfall and stronger to possibly severe
thunderstorms at times over the forecast district during the
longer term should be experienced Saturday evening, Monday and
then again by late week.

Finally, below seasonal late May maximum temperatures are
projected from Saturday into Tuesday, with maximum temperatures
then expected to run near to slightly above late May/early June
climatological averages from Wednesday into next Friday. Also,
near to above seasonal minimum temperatures are anticipated during
the longer term.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1128 PM MDT Fri May 26 2017

Upper disturbance will track southeast across the flight area over
the next 24 hours. Effects of system are already showing up over
the eastern plains where a cold front is pushing south along the
front range, developing low clouds behind it. Front will continue
southward progression overnight, helping prime the atmosphere for
Saturday. During the day Saturday, an upper level disturbance
will track southeast, triggering fairly widespread showers and
thunderstorms across the flight area through the afternoon into
the evening hours. This will result in flight category reductions
as the precipitation moves through. There will also be a risk for
a few strong thunderstorms producing lightning, wind, hail and
heavy rain hazards. Additionally, snow showers will be possible
in the mountains.

The KCOS and KPUB TAF sites will both see the threat of low
clouds moving in tonight into early Saturday with mostly MVFR
CIGS possible. Then, Saturday afternoon and evening, both sites
will see decent chances for convective precipitation to move
through, both in the form of showers and thunderstorms. KALS will
likely not see the low clouds move in but the site will see at
least a slight chance of a shower or thunderstorm moving through
the terminal generally between 21z and 03z Saturday afternoon and




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