Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 240520

Area Forecast Discussion
National Weather Service Pueblo CO
1120 PM MDT Wed Aug 23 2017

.SHORT TERM...(This evening through Thursday)
Issued at 350 PM MDT Wed Aug 23 2017

Isolated thunderstorms were developing over the mountains again this
afternoon, with greatest coverage along and north of the Arkansas
River. Expect storms to continue to develop and push eastward away
from the higher terrain from late afternoon into the evening, though
coverage will remain generally isolated as upper forcing remains
weak. Enough instability (CAPE 1-2k J/KG) on the plains to keep a
low threat of an isolated storm in place along and east of I-25,
though latest HRRR and 18z NAM now show little in the way of
convection through the evening. Storms fade fairly quickly in the
evening, with persistent sly flow across the plains likely leading
to some patchy fog along the KS border toward sunrise.

On Thu, upper trough moves across the state while a weak cold
front drops south through the plains. Moisture remains in place
across the region, leading to some fairly healthy CAPE (2k J/KG)
along and ahead of the boundary in the afternoon. Given the stronger
forcing and instability, area should see more widespread and
vigorous convection, with perhaps a severe storm or two over
the plains where instability is greatest. Main argument against more
widespread severe storms is weak 0-6km shear of only 20-30 kts,
so SWODY2 of only marginal risk over the eastern plains looks
reasonable at this point. Max temps look little changed, with
near seasonal readings at many locations.

.LONG TERM...(Thursday night through Wednesday)
Issued at 350 PM MDT Wed Aug 23 2017

Outside of Thursday evening(which is expected to be active due to
a healthy passing upper disturbance), a relatively tranquil
meteorological pattern is anticipated during the balance of the
longer term as varying degrees of upper ridging impacts the
forecast district.

At this time, main longer term meteorological concerns appear to
be temperatures and pops for the forecast district.

Recent longer term computer simulations, forecast model soundings
and PV analysis indicate that upper ridging centered near EL
Paso, Texas Thursday evening shifts into the 4-Corners region by
Saturday before relocating over Nevada and Utah from later this
weekend into next Wednesday.

In addition, varying degrees of eastern Colorado lee-side
troughing is anticipated from Friday into Saturday night and
then again from later Monday into next Wednesday.

In addition, at this time, it appears that the strongest upper
disturbances impacting the forecast district during the longer
term will be noted into Thursday evening, from later Sunday into
Sunday night and then again from later Monday into Tuesday night.

The combination of these factors as well as adequate atmospheric
moisture will allow basically daily rounds of isolated to
scattered primarily afternoon and evening pops(generally favoring
higher terrain locations) during the longer term.

At this time, the highest potential for more widespread precipitation
should be noted from Thursday evening into Thursday night, later
Sunday into Sunday night and then again from later Monday into
Tuesday evening. Also, as has been the case, minimal gradient wind
and fire weather concerns are anticipated during the longer term.

Finally, minimum and maximum temperatures should generally run
above late August climatological averages over the majority of
the forecast district during the longer term.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1112 PM MDT Wed Aug 23 2017

Generally VFR expected at KCOS, KPUB and KALS terminals next 24
hours. Isolated thunderstorms will continue over the flight area
until a little past midnight. Gusty winds up to 40 mph and local
MVFR/IFR CIGS/VSBYS will be possible with storms. Storms diminish
overnight with some patchy fog developing on the eastern plains
near the Kansas border toward sunrise. On Thursday, thunderstorms
will be slightly more numerous as a weak upper disturbance moves
across Colorado and a cold front drops south through the plains.
There will be a chance of thunderstorms at all terminals after
about 20z, with a chance for a few stronger storms producing hail
and brief MVFR/IFR/LIFR conditions along and east of I-25.




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