Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Riverton Wyoming
244 am MDT Wednesday Sep 17 2014
Short term...today through Friday night
Shower activity will continue to move through portions of the
forecast area this morning. An isolated lightning strike is not out
of the question. The ridge of high pressure remains over the area
with warming temperatures expected over the next couple days. Gusty
wind will develop over southern Wyoming during the afternoon
hours...with wind weakening through the evening hours.
The ridge of high pressure continues to slide east through the
forecast area over the next few days...with the axis reaching
outside of County Warning Area boundaries by late Thursday morning. Another push of
moisture expected with the departure of the ridge...especially
impacting the western mountains. In addition... a cold front will
sweep through the area late Thursday and into Friday. Cooler
temperatures are expected with increasing moisture. Showers and
thunderstorms remain most favorable over the western zones.
Long term...Saturday through Wednesday
In wake of the system Friday...mainly dry conditions are expected
Saturday with slightly above average temperatures. A cut off upper
low over California Saturday is projected by global models to push
into the Great Basin Sunday and then into the cowboy state Monday.
This would push some convection into the south/southwest Sunday and
over much of the area Monday if this track comes to fruition. Mainly
dry conditions with seasonal to slightly above average temperatures return
Tuesday and Wednesday.
Isolated showers will end by 12z east of the Continental Divide.
Isolated showers and thunderstorms will form over western Wyoming after
19z and this activity will progress eastward and impact some places
east of the Continental Divide from 21z until 03z Thursday. Outflow
wind gusts to 35 knots will be likely at times near storms. VFR
conditions will occur through the forecast period.
The ridge of high pressure remains over the area through Thursday.
However...enough moisture will move into the area to generate some
afternoon showers and thunderstorms. Additionally...some gusty wind
will develop across southern Wyoming where daytime humidity may dip
into the low teens. While this may impact fire weather
behavior...conditions will not be critical as fuels across the
impacted areas are currently listed as not critical. A cold front
moving through the area late Thursday and through Friday will bring
a wind shift across the area...with increasing shower
coverage...especially over western Wyoming.