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Area forecast discussion 
National Weather Service Pueblo Colorado
414 am MDT Wednesday may 27 2015

Short term...(today and tonight)
issued at 337 am MDT Wednesday may 27 2015

Currently...the upper ridge axis was moving east across the Colorado/Kansas
state line early this morning...and ongoing thunderstorm activity
has exited into Kansas and NE. There remains a residual cloud shield
over the far eastern plains as of 330 am...which is expected to
greatly diminish by sunrise. Temperatures have dropped into the 40s to
around 50f for much of the area so far this morning...and 30s for
the high valleys.

Today and tonight...the upper low over Washington and Idaho this morning is
forecast to gradually drop to the southeast across Idaho and Montana over the next
24 hours. This will help amplify the west-SW flow across the 4
corners...and models indicate that the westerly flow will finally be
realized in some part at the surface for the forecast area
today...resulting in warmer temperatures. 2-3 degree c warming at 700 mb should
help boost afternoon maximum temperatures to near 80f for many plains
locations...with lower 70s for the high valleys. As for shower and
storm activity...hrrr and other hi res models imply that activity
will once again begin over the higher terrain in the 17-19z time
frame...then slide east across the i25 corridor between 22-24z. The
dryline will of course reside somewhere along the Colorado/Kansas state
line...and Storm Prediction Center guidance indicates that the there is the chance for
severe storms across the east plains this afternoon and evening...most likely
beginning after 23z. The main threats will be large hail and damaging
winds. Moore

Long term...(thursday through tuesday)
issued at 337 am MDT Wednesday may 27 2015

..increased chances of rain for Thursday afternoon through Friday
night/early Saturday...

Upper trough moves into western Colorado on Thursday with energy ejecting
out of the mean trough across Colorado fairly early in the day. This may
suggest an earlier start to convection on Thursday. Focus areas for
thunderstorms will be across the mountains initially...along a
developing dry line across the far southeast counties during the
afternoon...and along the Palmer Divide as the front drops into
the vicinity during the late afternoon and early evening hours.
There could be one or two strong to severe thunderstorms across
portions of Kiowa/bent/Prowers/Baca counties Thursday afternoon
through early evening where convective available potential energy could be running around 2000+
j/kg. However 0-6 km shears do not look terribly impressive as low
level flow if forecast to become more south to southwesterly with
time...and to add to the uncertainty...GFS more aggressively mixes
the dryline eastward into Kansas Thursday afternoon...so there are some
uncertainties regarding storm strength on Thursday. Meanwhile...locally
heavy rainfall may be an increasing concern for the Pikes Peak
region burn scars depending on the timing of the front.

Front moves through the plains Thursday night and may keep a few
showers and thunderstorms going into the early overnight hours out
east. With the upper trough dropping in from the northwest...its hard
not to keep at least some isolated probability of precipitation across the mountain areas
through Friday morning and have made some minor adjustments to pop
grids. Upper trough then drops slowly southeastward across the area
on Friday. Lots of uncertainties this day. With front dropping
through the plains...should definitely see another cool down with
morning showers across the mts becoming more widespread across the
lower eastern slopes of the southeast mountains Friday morning as
upslope flow develops. Dew points drop off a bit behind the front
though...but still remain in the 40s. Given the cool air aloft
associated with the upper trough...don't think there will be much of a cap
by afternoon...even across the plains...but amount of instability
will also be dependent on getting some breaks in the clouds and
retaining some of the low level moisture. So this day could be
dominated by more stratiform showers for the southeast mts/adjacent
plains...with embedded thunderstorms during the afternoon/evening
hours. Either way...upslope flow focuses best chance for rain
across the southeast mts/I-25 corridor...and potential for flash flooding
on burn scars will be elevated this day. Doesn't appear that convective available potential energy
will be high enough to support the potential for severe
thunderstorms just yet...but again may have to watch how this
evolves as deep layer shears will be increasing given easterly low
level flow setting up beneath west to northwest flow aloft. Bottom
line is...strength of thunderstorms and potential for heavy rain
producing thunderstorms will depend highly on the cape this day.

Sheared out upper trough gradually shifts through southeast Colorado Friday
night...and should see stratiform showers along the southeast mts shift
southward into nm by Sat morning. May have to watch for heavy
rainfall on burn scars in and near the southeast mountains into the
overnight hours though nam12 is much less gung Ho with quantitative precipitation forecast amounts
during this period than GFS. More than likely rainfall rates will be
below the typical flash flood thresholds in more stratiform
rainfall overnight...but those thresholds may end up lower
depending on what falls across these areas Thursday/Thursday night. Area
rivers and streams may experience another round of high flows
depending on where and how quickly rainfall falls on the previous
days.

Upper ridge builds in for Saturday with enough residual moisture to
warrant isolated to scattered afternoon showers and thunderstorms
across the mountains. Southeast plains may be too cool and capped
for thunderstorms on Saturday. Upper ridge axis translates into
central Colorado by Sunday bringing drier and warmer temperatures to the
region. There will still be sufficient moisture for afternoon
thunderstorms across the mountains.

Next upper trough pushes inland early next week across the Pacific
northwest on Monday...then into the northern U.S. Rockies and Idaho region
by Wednesday. Southerly low level flow brings return moisture into
the southeast plains Monday afternoon...bringing back a chance for
thunderstorms along the dry line Monday across the eastern counties.
Meanwhile...mountain areas will see the usual diurnal thunderstorm
chances. Given the track of the upper trough and resultant SW flow
across southern Colorado...it appears dry line will be wavering across the
southeast plains Tuesday and Wednesday aftns...which should keep the threat for
stronger convection east of the I-25 corridor...however this is
all dependent on the southward extent/track of the next upper trough
which is likely to evolve over the course of future model run
cycles...so stay tuned. With 700 mb temperatures advertised to
increase to between +10 and +14c...we should see the return of 80
degree readings for the southeast plains as we go into June...with 60s
and 70s for the Mountain/Valley communities. -Kt

&&

Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 337 am MDT Wednesday may 27 2015

Generally VFR conditions across the region...including the three
main taf sites of kcos...kpub and kals over the next 24 hours.
Afternoon/evening convection between 18z and 06z may produce intermittent
MVFR conditions under brief heavier rainfall...even down to IFR
under stronger storms.

&&

Pub watches/warnings/advisories...
none.
&&

$$

Short term...Moore
long term...knots
aviation...Moore

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