Area Forecast Discussion
Issued by NWS Pueblo, CO

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960
FXUS65 KPUB 280950
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
350 AM MDT Fri Jul 28 2017

.SHORT TERM...(Today and tonight)
Issued at 344 AM MDT Fri Jul 28 2017

Currently...

Except for a few isolated showers over the region, it was dry across
the fcst district. It was uncharacteristically moist as dewpts were
well into the 60s across the plains and 50s in the most of the
valleys. The monsoon plume was well established over the region as
per water vapor imagery. On the larger scale, a few thunderstorms
were rumbling up in the vicinity of extreme ne CO. Numerous showers
and storms were located over AZ and NM with some showers in sw CO.

Today...

For the most part, with limited forcing over the plains, the lower
elevations are likely to remain dry today. The best chance of any
precip over the lower elevations will be over the Palmer Divide and
Raton Mesa during the late afternoon time period.

The mountains on the other hand will see isolated to scattered
storms by later this morning with showers and storms becoming
numerous by afternoon. Heavy rain will be likely and flash flooding
along with rock/mudslides will be possible.

Overall, we will have more instability today as temps will be a few
degrees warmer than yesterday. Guidance is showing at least 2000
J/KG of CAPE over nearly all of the plains by later this afternoon.
Some shear is note, but it is weak, generally below 20 knots.

Tonight...

Things will likely be active over the entire region this evening.
Some guidance (Hi res NAM) is showing we will see quite a bit of
activity over the plains while others are not as active, but all
guidance does show we will see at least scattered heavy rainers over
the plains and mountains this evening. Best chance overall will
generally be along and north of US-50.  Likewise, expect we will see
a threat of heavy rain once again with the possibility of flash
flooding, especially in areas which saw heavy rain over the last few
days.

Storms will be slow to dissipate tonight so expect we will see
showers and storms last into the early morning hours.

.LONG TERM...(Saturday through Thursday)
Issued at 344 AM MDT Fri Jul 28 2017

...Active monsoon pattern continues through the middle of next
week...

Monsoon moisture cycling northward into the upper high centered
across the southern/central rockies will keep an active pattern
across southern CO through the early to middle part of next week.
The mountains look active every day with diurnally driven afternoon
showers and thunderstorms, and with layer specific humidities
remaining high, heavy rain and flash flooding will be the primary
concerns, especially for burn scars and locations with
susceptible soils. Across the plains, placement of heavy rainfall
with MCSs is the primary challenge and these get increasingly
difficult to predict towards the latter parts of the forecast as
much will depend on how much stabilization occurs from the
previous days convection.

As for specifics, Saturday looks like an active day for not only
the mountains but the plains as well. Models lift the frontal
boundary back northward during the day with placement of MCS
Saturday evening across portions of southeast to east central CO.
With dew points in the 60s, NAM12 keeps afternoon CAPEs in the
1000-2000 J/kg and deep layer shears in the 15-30 kt
range with highest values across the north. SPC has marginal risk
for severe thunderstorms across the plains, which looks on
target. May end up needing a flash flood watch this day for a
large portion of the area, but will need to see how Friday
unfolds first. Showers and thunderstorms will continue most of the
night across the plains as low level jet cranks up. Meanwhile,
active monsoon plume should keep showers and isolated
thunderstorms across the mountains for a good part of the night as
well.

Sunday will be highly dependent on the amount of destabilization
which can occur across the plains.  NAM keeps it cooler and more
stable behind Sat night`s MCS across the eastern half of the
forecast area.  GFS is more gung ho on QPF across the southern
portions of the southeast plains Sunday evening, mainly south of
highway 50. It will all depend on how far south the front gets
driven as it gets reinforced by MCS outflow. For now will play
slightly lower pops across the plains on Sunday, but can`t really
pull pops entirely as to some extent NAM12 may be stabilizing
things too much. Really not much change in the layer specific
humidities across southern CO so heavy rain and threat for flash
flooding will continue, particularly across the mountains.

Upper high builds northward across the western U.S. but we never
really loose the northward fetch of monsoon moisture across southern
CO, so Monday and Tuesday still look active, particularly for the
mountains.  By the latter part of next week northerly flow around
the west side of the more amplified western U.S. upper ridge tries to
drive some drier air into the region, suggesting a downward trend
in thunderstorm coverage by Friday. -KT

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 344 AM MDT Fri Jul 28 2017

Morning low clouds are expected to occur over the KCOS area with
KPUB an KALS being VFR. KCOS and KPUB should be VFR later this
morning well into the afternoon. Storms will likely begin to affect
the KCOS by late this afternoon and especially this evening. Storms
will likely affect KPUB by this evening.

KALS will likely see some storms by mid afternoon and may last
into the evening.

Depending how much rain falls at the TAF sites, we may see some
morning low clouds at all of the taf sites SAT morning.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HODANISH
LONG TERM...KT
AVIATION...HODANISH



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