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Area forecast discussion 
National Weather Service Denver/Boulder Colorado
832 PM MDT Thursday Oct 30 2014

issued at 832 PM MDT Thursday Oct 30 2014

Northeast flow around a surface high over the northern plains will
push a shallow and cool airmass into eastern Colorado overnight.
Airmass will be up to around 7000 feet mean sea the higher terrain
will be above this cooler air. Fog and low clouds will be possible
over the eastern plains and across northern parts of the Front
Range early Friday morning. Updated the forecast to spread the
patchy fog farther west and increased cloud cover over the eastern
plains. Also adjusted winds and temperatures towards current


Short term...(this afternoon through friday)
issued at 350 PM MDT Thursday Oct 30 2014

Satellite pictures are still showing very little cloudiness over
the forecast area right now. Weak upslope winds are covering most
of the plains right now. Models show a fairly high amplitude upper
ridge axis to push across Colorado later tonight through Friday.
The flow aloft is weak. The qg vertical velocity fields show
benign synoptic scale energy over the County Warning Area tonight and Friday. The
boundary layer wind forecasts show an easterly component to the low
level winds over most of the plains tonight and Friday...mostly
southeasterly. For moisture...some of the models have some in the
lower levels...mostly over the eastern half of the plains. There
is tad here and there in upper levels as well. Will leave the fog
in over the eastern plains that is currently in the gfe grids.
There is nothing on the quantitative precipitation forecast fields. No probability of precipitation. For temperatures...
Friday highs will be very close to this afternoon's highs...maybe
a tad cooler.

Long term...(friday night through wednesday)
issued at 350 PM MDT Thursday Oct 30 2014

For Friday night into Saturday...upper level ridging will remain
in place through Saturday. Temperatures Friday evening will be
cooler...especially on the plains as cool southerly flow
continues to move out as the ridging builds in from the southwest.
Temperatures on Saturday will bounce back to above seasonal
normals with highs reaching into the lower 70s. Middle level moisture
will increase through the day as the positively tilted trough over
the west pulls in tropical moisture from the southwest. No
precipitation is expected during the day Saturday but upper level
clouds will increase keeping temperatures moderated but still

For Sunday...the positively tilted trough will track towards the
Great Basin region Sunday into early Monday where it is currently
forecasted to split into a NE to SW direction. This system remains
challenging with the various deterministic models as it seems
they are having a hard time grappling with the split jet and
energy. Both models have a Lee trough setting up over the east
Sunday afternoon which will aid in keeping the brunt of the
moisture over the mountains. Temperatures would get cold enough
for the mountains to receive some precipitation in the form of
rain and snow showers by Sunday morning. Temperatures will be
cooler in the mountains will highs in the 30s and 40s with 60s for
the plains.

Weather into Monday morning differs with the models as the ec is
deeper with most of the energy over southern nm with the GFS
being faster. Most of the precipitation for the foothills and
plains will occur Monday morning into Tuesday morning but will
stay modest on exact amounts and type until models align
better...hopefully over the next few runs.

For Tuesday afternoon and the trough moves to the
southeast upper level ridging returns. Clouds will dissipate by
Wednesday evening leaving temperatures to slightly below normal on
Tuesday to slightly above on Wednesday.


Aviation...(for the tafs through 06z Friday evening)
issued at 832 PM MDT Thursday Oct 30 2014

East to southeast and occasionally south winds will prevail
through 12z. A Denver cyclone is expected to form by 12z...making
the wind direction forecast challenging. Appears winds may turn to
the northwest around or just after 12z. This could also pull in
the low clouds and fog over the eastern plains. The chance for
fog will be from 11-16z. The cool moist layer is shallow. So if
any low clouds form...expect them to be under 1000 feet.
Visibility in fog could drop to a quarter mile if it is able to
migrate far enough west.


Bou watches/warnings/advisories...


short term...rjk
long term...Bowen

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