Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 200529

Area Forecast Discussion
National Weather Service Pueblo CO
1129 PM MDT Wed Apr 19 2017

Issued at 1120 PM MDT Wed Apr 19 2017

Added some low pops for thunderstorms to portions of the eastern
plains for a few hours overnight to account for ongoing convection
developing along and north of a Colorado Springs to Lamar line.

UPDATE Issued at 749 PM MDT Wed Apr 19 2017

Updated grids for wind shift/frontal boundary backing across the
I-25 corridor at this time.


.SHORT TERM...(This evening through Thursday)
Issued at 345 PM MDT Wed Apr 19 2017

...Weather Pattern becomes more active for Thursday/Friday...

Strong WSW winds aloft and shortwave crossing the northern U.S.
Rockies has brought windy conditions to much of southern Colorado
today. Stalled cold front which extends from Simla through Eads into
Northeast Prowers county will get a secondary push this evening as
surface high descends through the plains.  Gusty west winds will
continue through early evening before the front moves through
shifting winds out of the north to northeast.  HRRR has the front
through most of the southeast plains by 03-04Z.  Could see some
localized gusts to around 40 mph behind the front...particularly
across the far east plains across Kiowa...Bent...and Prowers
counties and Baca counties this evening.

Winds will shift around from the east to southeast overnight with
some models suggesting a stratus layer could develop along the lower
eastern slopes of the southeast mountains early Thursday morning.

Next upper trof will be moving into western CO Thursday afternoon.
Showers and thunderstorms will develop across the mountains around
or shortly after 18z.  Southeast low level flow doesn`t have
sufficient time to return higher dew points back westward across the
plains...and atmosphere will be capped out that way through th. e
afternoon. Main concern will be the potential for thunderstorms over
the mountains to produce rainfall on burn scars.  GFS and NAM both
suggest a few tenths of an inch falling on Junkins burn scar with
snow levels remaining quite high...around 9500-10000 feet through
the day. CAPEs are not terribly impressive (perhaps around a couple
hundred J/kg) so higher probability is for rainfall rates to stay
sub warning criteria.  But given the nature of convection and the
susceptibility of soils for our newer burn scars (Junkins and Hayden)
...a low risk is there.  Have trended pops downward through the
early part of the day as timing puts greatest coverage of
showers/thunderstorms after 20z over the mountains.
inch or two of snow will be possible across the higher peaks during
the late afternoon.  -KT

.LONG TERM...(Thursday night through Wednesday)
Issued at 345 PM MDT Wed Apr 19 2017

Latest models in decent agreement of long wave upper trough digging
across the Great Basin and into the Rockies Thursday night, with the
models still differing on where the system closes off on Friday. The
NAM remains the furthest north with the developing low across
northeastern Colorado and the 12Z operational GFS is the furtherest
south with the low across extreme southeast Colorado and remain
outliers. The 12Z GFS Ensemble data, the 12Z ECMWF and Canadian
models are in good agreement of the low developing across the
southeast plains late Friday morning and then continuing into south
central Kansas Friday night, with a secondary lobe of energy digging
across eastern Colorado within developing north to northwest flow
through the day on Saturday.

With that said, followed EC/Canadian/GFS ensemble data and should
see showers and a few embedded thunderstorms increasing in coverage
across the higher terrain Thursday afternoon, which spread east
across the high mountain valleys and out across the the eastern
Plains into early Friday morning. Best chances of showers continuing
overnight looks to be across the Central Mountains through the Pikes
Peak region, where low level upslope looks to enhance convection.
Snow levels to remain high AOA 10K feet initially, though could
lower to 8000 feet into early Friday morning, before rising again
through the day. At this time, grids have generally 3 to 8 inches
above 10,000 feet across the Sawatch, Mosquito and Rampart Ranges,
with 1 to 3 inches below.  Wrap around precipitation from the Palmer
Dvd early Friday morning spreads south and east generally from a COS
to LAA line through the day Friday with breezy northerly winds
developing across the eastern plains into Friday afternoon.

Cool northerly flow aloft will allow for possible freeze/frost
potential across the plains Friday night/Saturday morning, though
may be too many clouds to be a widespread enough for highlights.
Developing easterly upslope and the secondary lobe of energy digging
across the area to allow for a few showers across the eastern mts
and immediate adjacent plains Saturday afternoon.

Warmer and drier weather remains in the offing for Sunday through
the middle of next week with a few minor embedded waves within the
moderate westerly flow bringing chances of showers to mainly the
higher terrain for the middle of the work week and a possible
stronger system bringing chances of showers across all the of area
on Thursday.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1120 PM MDT Wed Apr 19 2017

Cold front through the eastern plains with upslope flow across
the eastern mountains and plains overnight and through the day
Thursday. HRRR develops lower clouds over ern mountain slopes by
early Thu morning, though most model guidance keeps lower cigs
west of both KCOS and KPUB, and will keep cigs vfr at both sites
into midday Thu. Expect -shra/isolated -tsra to develop over the
higher terrain after 18z Thu as upper wave approaches, with
potential for IFR conditions increasing after 23z at KCOS and KPUB
as convection moves east off the mountains.




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