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Area forecast discussion 
National Weather Service Pueblo Colorado
432 am MDT Thursday Aug 21 2014

Short term...(today and tonight)
issued at 346 am MDT Thursday Aug 21 2014

Southwest flow aloft ahead of the closed low moving through Southern
California today will bring a slight increase in middle and high level moisture
across the region. Forcing looks relatively weak as upper low is
still well off to the southwest. However with afternoon
heating...isolated to scattered showers and thunderstorms will
develop across the mountains once again. Weak boundary pushing
southward through the plains this morning will stall across northern nm
and the OK Panhandle this afternoon before shifting back northward
through the evening hours as the upper low begins to lift into the
Desert Southwest. This puts a convergence zone across southern
portions of the southeast plains late this afternoon and could be
the focus for thunderstorm development as well.
Overall...thunderstorm coverage may end up similar to
yesterday...and surface dew points are still not all that impressive as
models show them falling off into the 30s and 40s for most areas by
afternoon. Thus cape values remain generally under 500 j/kg though
there could be a pocket of higher cape (up to 1000 j/kg) across the
far southeast plains if dew points can stay up in the lower 50s.
However deep layer shears remain weak across this area...so think
main threat with thunderstorms today will be locally heavy rainfall.
Over the mountains...thunderstorms will be capable of producing
some brief moderate to heavy rainfall...but threat for flash
flooding on area burn scars looks low at this point due to high
LCLs.

Tonight...the upper low ejects to the northeast as a fairly strong
upper trough drops into the Pacific northwest. Timing is slower than
the model runs from last evening. Two areas of focus will exist for
evening and overnight showers and thunderstorms. One across the
Continental Divide region as moisture and upper lift increases ahead
of the approaching system late. Second area will be across the
southeast plains and Palmer Divide region where low level jet
impinges over northward advancing warm front. Threat for rainfall
on the Waldo burn scar will likely increase through the evening up
until shortly after midnight...then focus shifts northward into
northeast Colorado. With upper lift approaching The Four Corners
region...looks like an area of showers/embedded thunderstorms will
be approaching the West Fork burn scar after 3 am. Overall
precipitation rates don't appear great enough to warrant any flash
flood watches...and the threat will be most likely confined to burn
scars. Went on the warm side of guidance for lows tonight with
increasing cloud cover ahead of this next system. -Kt

Long term...(friday through wednesday)
issued at 346 am MDT Thursday Aug 21 2014

Fairly good agreement between the models through Monday...then
confidence dips as the solutions diverge for Tuesday and Wednesday.

Friday...this looks to be the most active day of the extended
period. The upper low over the desert SW is forecast to be weakening
and lifting across the 4 corners through the day...then merging with
the northern trough through the evening. The nearly constant
moisture feed will remain in place...with the added benefit of both
a surface cold front dropping down eastern Colorado through the morning...and
favorable dynamics aloft as the wave lifts to the NE. Save for the
far east along the Kansas border...temperatures should be much cooler under
plenty of cloud cover and convective activity. For the time
being...it does not look like a severe weather day...but there will be a
heightened chance for periods of heavy rain which could cause
problems for area burn scars. Maximum temperatures are expected to be in the
70s for the high valleys...lower 80s for the i25 corridor and around
90 for the far east. As for probability of precipitation...scattered to likely probability of precipitation for the
higher terrain and valleys...and isolated for the plains.

Saturday...the upper trough slides to the east across Montana on
Sat...and a piece of energy rotating around the low should keep
light showers going for the Continental Divide through the morning hours.
Enough moisture will be present for isolated convection over the mts
through the afternoon...but by later in the evening downslope flow is
expected to dry things out in the lower levels and after midnight
probability of precipitation should drop off. Temperatures are forecast to be slightly warmer on
Sat...climbing to the upper 80s to around 90 f for the plains and
near 80 f for the high valleys.

Sunday and Monday...broad upper trough over the western US will keep
a daily threat of isolated to low end scattered probability of precipitation for the higher
terrain each afternoon and early evening...with maximum temperatures in the 70s and
80s...nearing 90 f for the eastern plains.

Tuesday and Wednesday...ec and GFS models slip out of phase starting
Tuesday...with the ec about 24 hours slower on sweeping the trough east.
With such disparity...decided to hold steady on the temperature forecast
while keeping probability of precipitation generally in the isolated category. Grids do
reflect a slight uptick in probability of precipitation for Tuesday afternoon and evening for the
plains...but this will certainly have to be revisited over the next
few days. Moore

&&

Aviation...(for the 12z tafs through 12z Friday morning)
issued at 346 am MDT Thursday Aug 21 2014

VFR conditions expected at taf sites through the next
24 hours. North winds this morning will gradually decrease and
shift around out of the east then southeast for kcos and kpub by
this afternoon. Thunderstorms will develop over the mountains
around 18z...with isolated thunderstorms possible across the
adjacent lower elevations and southeast plains during the late
afternoon and evening. Of the three taf sites...probability looks
lowest for kals. Will maintain thunderstorms in the vicinity for both kcos and kpub...though
looks like threat will likely hold off until after 22z. Kcos may
have a better chance of thunderstorms in the vicinity during the evening and overnight hours
as another northerly surge drops south of the Palmer Divide.
Again...coverage looks isolated...so thunderstorms in the vicinity should suffice in tafs for
now. Erratic gusty winds up to 35 kts...lightning and brief moderate
to heavy rainfall will be the primary storm threats today. Showers
will spread into the southwest and central mountains late tonight as
the storm system approaches the 4 corners region after 06z. Should
start to see MVFR to local IFR conditions across the higher terrain
west of kals to kank to klxv towards 12z due to incoming -shra and
isolated embedded -tsra.

&&

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

$$

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

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