Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 271017

Area Forecast Discussion
National Weather Service Pueblo CO
417 AM MDT Thu Jul 27 2017

.SHORT TERM...(Today and tonight)
Issued at 341 AM MDT Thu Jul 27 2017

...Still Ongoing Precipitation Across the Plains this Morning...

MCS precipitation continues across the plains this morning.  Rates
are surprisingly high.  Airmass is a bit subtropical with mixed drop
size distribution, resulting in general underestimation of
precipitation rates/amounts by radar.  So, some of the radar returns
that look rather innocuous are not so innocuous.  Ongoing MCS
precipitation will continue for a while this morning, gradually
shifting south and fading with time.  All the clouds and
precipitation left behind by the MCS will leave behind a more stable
airmass across the plains today.  This should result in considerably
less afternoon precipitation across most of the plains. A little
more questionable from the mountains westward, though, as there will
likely be less stabilization in those areas and more opportunities
for lifting through terrain forcing.  So, in general, would expect
another round of afternoon and evening storms to develop over and
near the mountain areas today, with just isolated activity out east
across the plains.  And by isolated activity out across the plains,
I`m referring to this afternoon, following the departure of this
morning`s more widespread rain.  As far as available moisture,
nothing has really changed since yesterday. Blended Total
Precipitable Water values remain high, currently showing up at 140
to 180 percent of average across southern Colorado.  Low level
moisture remains equally impressive with 60s widespread across the
lower elevations and 50s across the high valleys.  It`s just a
matter of getting enough forcing to overcome any stability issues
and realize the moisture that is available for precipitation.  Any
storms that develop today will again be heavy rainers capable of
flash flooding, particularly over burn scar areas, urban areas and
over any areas that got pounded from storms yesterday through this
morning.  Other storm concerns will include lightning, strong gusty
outflow winds and possibly some spots of hail too.

.LONG TERM...(Friday through Wednesday)
Issued at 341 AM MDT Thu Jul 27 2017

Won`t try to get too fancy on the details because each day`s
convective patterns will be strongly influenced by the previous
day`s patterns. Models are all over the place trying to peg the
timing and location of precipitation maxima over the next
several days. Currently, most models agree on a couple of less
active (more stable) days across the plains while areas in and
near the mountains remain active. Then, they have it turning
more active across the plains again on Saturday and Sunday,
followed by a down day on the plains Monday and then another
active day Tuesday. In any event, the mountains remain active
right on through the entire period. Timing the location and
intensity of each day`s precipitation through the extended
forecast period would tend to be fruitless.  However, what
can be said is that the monsoon doesn`t appear to be going
anywhere anytime soon. Models all agree on keeping a moist
monsoon flow and light steering winds across the region for
the next several days. Heavy rain and flash flooding will
continue to be the main concerns. Burn scars, urban areas and
locations saturated from previous days rains will continue to
be the main targets.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 341 AM MDT Thu Jul 27 2017

Area of rain should be east of the KCOS and KPUB terminals by 12z
TAF issuance time.  VFR cigs may drop into the MVFR category this
morning as upslope stratus develops along the I-25 corridor. Stratus
will break around 18z for both terminals...with another round of
thunderstorms developing across the mountains.  With stable air over
the plains think that chances of VCTS at KCOS and KPUB are extremely
small as any storms should weaken quickly as they move into the I-25
corridor.  Will maintain an VCSH for now after 23z.  MVFR stratus
will likely reform after 03-04z for both KCOS and KPUB due to light
upslope flow into the overnight hours.

KALS will remain in a more unstable airmass today with VFR cigs
gradually decreasing this morning.  Storms will refire over the
mountains this afternoon, then move into the valley after 20z. Brief
VFR Cigs/Vis will be possible with storms until 02z with VCSH
lingering until 06z. -KT




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