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Area forecast discussion 
National Weather Service Pueblo Colorado
314 PM MDT Sat Jul 23 2016

Short term...(this evening through sunday)
issued at 243 PM MDT Sat Jul 23 2016

Wave passing by to the north has flattened the upper ridge slightly
today, and was pushing a weak cold front south through the plains at
mid-afternoon. While front has had little impact on Max temps today,
it has brought in a slightly drier/more stable airmass to portions
of the I-25 Corridor North of the Arkansas River, where cape has
fallen off to around 500 j/kg at mid-afternoon. Better instability
lies over the mountains and across the plains along and south of the
Arkansas River, and expect these areas to see slightly greater
convective coverage into the evening. Shear profiles again look
fairly weak, so gusty outflow winds and brief heavy rain will be the
main storm threats this evening, with a few mesoscale models
developing a broken line of convection pushing eastward across the
plains toward the Kansas border during the evening. Activity wanes
overnight, though a few spot near the Kansas border could hold on to a
some isolated tsra into early Sun morning.

On Sunday, frontal boundary hangs up near the nm border, with
upslope flow to the north of the front bringing back fairly deep
moisture and instability to most of the eastern mountains and
plains. Model progs suggest 2000+ j/kg cape over much of the plains
in the afternoon, and expect tsra coverage and strength to increase
most areas along and east of the mountains versus today. Severe
threat will increase with greater instability, though 0-6km shear is
still rather low (25-35 kts), with higher shear farther north over
nern Colorado. Main concern may end up being heavy rain, especially
Teller/El Paso counties where models develop fairly strong
convection after 21z. Over the mountains and interior valleys,
little change in the air mass, with another round of isolated to
scattered tsra expected. Max temps most locations will drift
downward a few degf, with most pronounced cooling over the plains,
where readings should stay below 100f for a change.

Long term...(sunday night through saturday)
issued at 243 PM MDT Sat Jul 23 2016

Models continue to indicate an active weather pattern through the
extended period with good model agreement and relatively moderate
ensemble spreads, mostly in the finer details.

Sunday night through Tuesday...high pressure aloft will begin to
build across the region and retrograde westward during the first
part of the work week. Several disturbances will shift across the
state keeping the area under active weather conditions.

Expect ongoing showers and thunderstorms across the region Sunday
night as a strong upper level disturbance drifts slowly east
across the plains. Moist low level upslope flow, modest
instability and weak shear will combine to produce the widespread
convection across the area. Both the GFS and NAM develop a strong
cluster of thunderstorms over the I-25 corridor during the evening
and shift it east across the plains overnight. Gusty outflow winds
and near severe hail are possible. Abundant moisture should allow
for locally heavy rainfall, with flash flooding a threat over burn
scars, and possibly down into Colorado Springs and Pueblo.

As the upper high builds westward, energy is forecast to track
southeast across Colorado Monday and Tuesday. Southerly low level
flow should keep moisture across the region allowing for daily
rounds of showers and thunderstorms. Low level upslope will likely
be regulated by left over outflow boundaries across the plains. If
outflow boundaries can keep low level flow easterly, it will help
pool moisture across the plains and help aid in precipitation
generation across the area. Initial thunderstorm develop will
happen by early afternoon over the mountains, spreading east into
the plains during the evening hours. Steering flows are forecast
to weaken as the upper high builds, with models indicating less
activity spreading east on Tuesday than on Monday. Locally heavy
rainfall will continue to be a threat with flash flooding possible
on burn scars along with areas that see heavy rain Sunday. Small
hail will also be likely with stronger storms.

Wednesday...models in good agreement with the upper high becoming
stationary over the Great Basin with northwest flow developing
across Colorado, while a broad trough forms over the Ohio Valley.
Lack of upper level forcing should keep shower and thunderstorm
develop limited to Wednesday afternoon and evening over the
mountains, with dry conditions forecast across the plains.

Thursday through Saturday...the upper high will remain over the
Great Basin with northwest flow expected across The Rockies.
Several embedded disturbances are forecast to drop across the
region in the northwest flow. Low level winds will be highly
dependent on cold fronts and outflow boundaries, which at this
time models have had a hard time with. Most indicate a boundary on
Thursday, with another on Friday night. Both would bring increased
low level moisture and upslope flow to the area. All models are in
agreement with bringing more widespread shower and thunderstorm
activity back to the area. Initial development over the mountains
is expected, with increased northwest flow aloft allowing storms
to move off the higher terrain and across the plains during the
evening and overnight hours. Locally heavy rainfall will be
possible. Mozley


Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 243 PM MDT Sat Jul 23 2016

Convection has been a little slow to initiate so far today, though
radar/satellite loops at 21z suggest tsra beginning to increase most
areas as atmosphere destabilizes. Will carry thunderstorms in the vicinity at all terminals
until around 03z, with gusty erratic outflow winds up to 45 kts the
primary storm threat. Thunderstorms will move east of the terminals
after 03z, with VFR conditions overnight and through 18-20z on sun.
After 20z, tsra chance increases again at all taf sites, and with
slightly deeper moisture over the area, suspect storm strength and
coverage will be greater than today, with areas of MVFR cigs/vis and
the threat for hail under the strongest storms.


Pub watches/warnings/advisories...


Short term...petersen
long term...mozley

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