Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 222100

Area Forecast Discussion
National Weather Service Pueblo CO
300 PM MDT Sat Jul 22 2017

.SHORT TERM...(This evening through Sunday)
Issued at 300 PM MDT Sat Jul 22 2017

...Flash Flood potential will continue into this evening for the
southern mountains and southern I-25 corridor.

Monsoon plume has shifted over the region with the upper trof axis
across east central CO progged by models to rotate southward through
the evening hours.  Associated reinforcing surge behind the front is
expected to bring drying into the north...while southern areas
continue to see upslope flow and dew points in the 50s.  High res
models have started shifting convection back northward across the
plains...and all model runs continue to hit the southern Sangres,
San Juans and southern portions of the Wet mountains with healthy
rainfall amounts through the evening.  Thunderstorm activity also
develops along the surface trof axis across the plains and all
activity congeals into an MCS across southeast CO which shifts
southward with time through the evening and early overnight hours.
Per coordination with surrounding offices have issued a Flash Flood
watch for the southern mountains and southern I-25 corridor through
9 PM this evening.  Main threat area will be south and west of a
line from Creede to Colorado City to Branson. Decided to throw in
the Wet mountains and northern Sangre De Cristo mountains due to
proximity and the highly susceptible nature of the Junkins and
Hayden Pass burn scar.  Thunderstorms may be less numerous for these
areas...but any storms today will be slow moving with the potential
to produce heavy rainfall.  So if impacted by one of these, flash
flooding would not be out of the question.

Activity rolls eastward onto the plains with a persistent area of
showers and isolated thunderstorms associated with an MCV continuing
across the San Luis Valley and southwest mountains into tonight.
Suspect models may be overdoing this latter feature, but with an
active monsoon plume over the area, will maintain some isolated
showers through the night across the mountain areas.

Sunday...thunderstorm activity should be less widespread as
northerly flow around the top of the ridge suppresses the monsoon
plume southward.  Doesn`t appear to be as much forcing tomorrow
either.  However all models maintain sufficient moisture for another
round of isolated to scattered thunderstorms over the mountain
during the afternoon.  Given less widespread nature of
thunderstorms, flash flood threat will be lower.  But certainly some
locally heavy rain will be possible with the more intense cells.
Temperatures on Sunday will be below normal.  -KT

.LONG TERM...(Sunday night through Saturday)
Issued at 300 PM MDT Sat Jul 22 2017

Sunday night-Tuesday...Monsoonal moisture shunted south and west of
the area on Sunday begins to work back into westerly Colorado Monday
and Tuesday within weak south to southwest flow aloft, as the upper
high across the region builds south and east of the Central Rockies.
With that said, should see decreasing chances of storms across the
eastern plains through this period, with scattered to numerous
afternoon and evening storms expected over the and near the higher
terrain, with best coverage shifting to areas along the ContDvd. The
increasing moisture and weak steering flow aloft will continue to
support locally heavy rainfall and the potential for flash flooding,
especially over and near area burn scars. Temperatures across the
area to be near to slightly above seasonal levels, especially across
the eastern plains.

Wednesday-Saturday...Weak westerly flow aloft can be expected across
the region through Thursday, with a few minor disturbances moving
across the northern fringe of the high across the Northern Tier of
States. On passing wave sends a cold front across the area on
Wednesday, with moist upslope flow expected across the eastern
plains on Thursday. This, along with the monsoonal moisture plume
progged across the state, will lead to an uptick in convection
across the eastern portions of the area, with scattered afternoon
and evening storms expected areawide. Again, main storm threats will
be locally heavy rainfall and the potential for flash flooding.

Moisture plume begins to slowly be shunted south and west of the
area Friday and into next weekend, as the upper high again rebuilds
into the Desert Southwest, leading to slowly decreasing chances of
afternoon and evening storms through the period. Temperatures at or
slightly below seasonal levels are expected through the extended


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 300 PM MDT Sat Jul 22 2017

KALS will have the best chance of seeing rain from around 20z
through 03z this evening.  Brief MVFR Cigs and gusts to 40 kts will
be possible with TSRA through this evening.  KCOS will see the
lowest chance for -TSRA...though there will be a brief window
between the 20-23z timeframe.  Will carry VCTS in the COS TAF for
now due to lower certainty. Winds will stay northerly with a
reinforcing surge behind the front by this afternoon.  KPUB could
see VCTS in 2 waves, one along a boundary between 21-23Z with
another round possible as thunderstorms push off the mountains later
this evening.  Will carry VCTS through at least 02z to account for
this possibility. Otherwise...expect clearing conditions overnight
as all activity shifts southward across the NM border.  Another
round of thunderstorms is expected for Sunday, but these will be
more isolated and confined to the mountain areas.  -KT


Flash Flood Watch until 9 PM MDT this evening for COZ067-068-



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