Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Pueblo Colorado
1121 PM MDT sun Aug 2 2015

Update...
issued at 1110 PM MDT sun Aug 2 2015

Threat of heavy rainfall overnight looks minimal as
satellite/radar loops and latest mesoscale models suggest thunderstorms and rain
will continue to fade...with mainly light convective debris -shra
across the higher terrain through the night. Will cancel the Flash
Flood Watch a little early and trim back overnight probability of precipitation most
areas.

&&

Short term...(this evening through monday)
issued at 235 PM MDT sun Aug 2 2015

..heavy rain possible over the mountains tonight...
..Another round of storms tomorrow...some on the strong side...

Main concern for the short term is potential for flash flooding over
the mountains through tonight. Scattered to numerous showers and storms
have already developed this afternoon...and as a strong shortwave
now moving through Arizona and Utah continues to translate to the NE this
evening...the threat for locally heavy rainfall will persist.
Latest guidance shows the associated upper low over Utah moving into
northwest Colorado by 12-15z Monday morning. Am particularly concerned by the
latest high res WRF and hrrr runs...which both show a strong band
of heavy precipitation moving through SW-central Colorado between 03z and 09z
tonight. This would coincide with strongest upper forcing from the
short wave. In coordination with kgjt and kabq have expanded our
Flash Flood Watch for the San Juans to include the rest of the
Continental Divide...along with the sangre Delaware cristo range...through 09z
tonight. This may have to be extended slightly if the banded heavy
precipitation gets a delayed start...but there is still some uncertainty
on how intense the precipitation will be...especially since the strongest
forcing will occur during the overnight hours when convection is
generally less intense. Nevertheless...anyone planning on being in
or traveling through the mts this evening and overnight needs to be
aware of the potential for flood-producing rains...which could
lead to sudden small stream rises...flooded roadways...and mud or
rock slides in the steeper terrain.

Tomorrow...the upper wave will continue to move to the NE during the
day...into southern Wyoming by 00z Tuesday. This will bring several more rounds of
convection to the area...particularly over the higher terrain. Low
level moisture will also increase over the plains. Along with
increased shear...this will raise the threat of some strong to
possibly severe storms over the area. It looks like the greatest
instability will be over the southeastern plains generally south of hgwy 50
and east of I-25...and this is where the strongest storms likely will
be during the afternoon. Lower temperatures aloft along with increased low level
moisture and precipitation/clouds will hold high temperatures a good 5-10 degrees
below the high temperatures from today...so will see mainly temperatures in the
70s and 80s Monday afternoon. Rose

Long term...(monday night through sunday)
issued at 235 PM MDT sun Aug 2 2015

Monday night...as an upper disturbance moves northeastward out of southeastern
Colorado and an upper trough moves northward into Wyoming...the isolated to scattered precipitation
across the forecast should come to an end around midnight. On Tuesday an
upper ridge axis will lie from Arizona into the Great Basin region...
resulting in west to northwest flow aloft over the forecast area. The latest
run of the NAM and GFS shows drier conditions for Tuesday...with mainly
just some isolated precipitation chances. Tuesday night surface high pressure backs into
eastern Colorado and is expected to bring increasing low level moisture and the
potential for some low clouds. As a result...the NAM prints out the
potential for some light precipitation over the far southeastern plains late Tuesday night
and early Wednesday morning...however will leave the forecast dry for now.

On Wednesday the upper ridge axis shifts eastward over Colorado with relatively dry
conditions expected through much of the day with mainly just some
isolated precipitation over and near the mountain areas. However a weak disturbance
may round the top of the ridge and move through eastern Colorado in the evening
hours to help kick off some convection across the plains. On Thursday the
upper ridge gets flattened across the forecast area as a shortwave
trough moves through Montana Wyoming and northern Colorado. Only some isolated precipitation is expected
Thursday afternoon...but then as that disturbance moves off into the
plains states the European model (ecmwf) is still showing an mesoscale convective system developing and
affecting portions of eastern Colorado by Thursday evening.

Friday an upper trough is expected to move over California...with an upper ridge being
over Colorado. Moisture still looks to be somewhat limited during the
day...with maybe just some isolated to scattered precipitation over the forecast area.
Then Friday night and Sat as that upper trough moves east-northeastward
into Idaho and Utah...monsoon moisture is expected to be drawn northward into
western Colorado again which will increase the chances for precipitation...especially
over the mountains and high valleys. As the upper disturbance moves eastward
across Montana and Wyoming Sat night...precipitation is expected to spread across the eastern
Colorado plains. Then by sun it looks like the forecast area will again be
cutoff from the monsoon moisture...leading to drier conditions again.

&&

Aviation...(for the 06z tafs through 06z Monday night)
issued at 1110 PM MDT sun Aug 2 2015

Still some showers over the mountains as of 05z...and will keep a
vcsh mention at kals until 09z to account for these...though
ceilings/visible at the terminal will remain VFR. On Monday...upper trough
moving through the area will likely trigger early thunderstorms and rain over the
mountains before 18z...with a threat of convection at all
terminals from 18z-19z into the early evening. Local MVFR/brief
IFR expected under heavier storms...as atmospheric moisture
remains plentiful. 01z-03z...convection will begin to diminish
over the mountains...with storms on the plains pushing into Kansas
after 03z.

&&

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

$$

Update...petersen
short term...rose
long term...28
aviation...petersen

National Weather Service Glossary of Abbreviations