Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Riverton Wyoming
202 am MST Wednesday Dec 11 2013
Short term...tonight through Friday night
Some low clouds noted over portions of northern Wyoming this
morning...with mostly clear conditions expected otherwise. Building
northwest flow expected today across the forecast area...with
generally dry conditions expected. Much of the forecast area can
expect warming temperatures today under the current pattern. Gusty
wind will continue across the wind corridor and the eastern slopes
of the central mountains today...with light wind expected otherwise.
This pattern will generally continue through Thursday as a ridge of
high pressure moves through the forecast area. This will keep dry
conditions across the forecast area.
Models then indicate the presence of an approaching wave of low
pressure for Friday...with snowfall impacting the area Friday
morning. This snowfall will primarily impact the western mountains
with some snowfall potentially moving into the western valleys. The
approach of this system may cause temperatures to cool slightly for
Friday...especially with increased cloud cover across the forecast
area. Any snowfall through Friday night is generally expected to be
Long term...Saturday through Wednesday
A relatively moist northwest flow will prevail through the extended.
This will keep chances of light snow across the northwest/northern
mountains through the period...possibly getting into the adjacent
lower elevations at times. The main storm track will be across
southern Canada into the northern plains and upper Midwest...with a
couple of clipper systems. The main impact from these systems will
be breezy to windy conditions at times. Not out of the question
some areas could approach high wind criteria. Temperatures look to
be seasonal to above average in the extended...a far cry from the
bitter cold that occurred over the forecast area in early
December. Speaking of Arctic air...the 00z GFS shows an Arctic
cold front pushing south across the area late next Wednesday into
Wednesday night...while the 00z European model (ecmwf) shows it pushing across the
area late Thursday into Thursday night.
West of The Divide...kjac-kbpi-kpna-krks routes.
Local MVFR ceilings will be possible in northwest Wyoming until 16z. Otherwise
VFR conditions will occur today and tonight. A gusty wind will occur
at the krks terminal site after 20z and continue through 12z
East of The Divide...kcod-kcpr-klnd-kriw-kwrl routes
Areas of low clouds will create some MVFR to IFR conditions until
14z. Otherwise VFR conditions will occur today and tonight. A gusty
wind will occur at the kcpr terminal site after 16z and continue
through 12z Thursday.
An area of high pressure will move through the forecast area for the
next couple of days. This system will bring generally dry conditions
with warming temperatures. Along with this improved conditions...
some areas of gusty wind will continue...mainly over the eastern
slopes of the central mountains...and across the wind corridor
between Rock Springs and Casper. The next opportunity for wintry
weather looks to be Friday when an approaching disturbance will have
the potential to spread snowfall across the western mountains and