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Area forecast discussion 
National Weather Service Denver/Boulder Colorado
424 am MDT sun Apr 19 2015

Short term...(today through tonight )
issued at 424 am MDT sun Apr 19 2015

Band of showers on the back edge of the upper low dropping through
Denver now...and should be clear of our forecast area by middle
morning. Cool and drier airmass upstream...but still some clouds
and shallow convection so I will hang on to the low probability of precipitation for today
and drop the highs slightly. In the late afternoon and evening
warm advection aloft kicks in and this should cap the convection
during this period...but this quickly leads to another moist layer
with neutral stability that should bring some light snow to the
mountains...more clouds for the plains again...and possibly a few
showers making it off the mountains later tonight. This does not
look like much...but again enough for the low probability of precipitation. How soon it
clouds up will determine low temperatures tonight. Airmass is
looking a little colder than what we had seen earlier...but the
clouds could offset it. For now it does look like there will be
widespread freezing temperatures with lows in the upper 20s in
most areas tonight.

Long term...(monday through saturday)
issued at 424 am MDT sun Apr 19 2015

West-northwesterly flow aloft is prognosticated for the forecast area
Monday through Tuesday...with an upper ridge axis moving into
Colorado Tuesday night. The speeds at jet level are pretty weak
and by Tuesday night the flow is very weak and due westerly.
The synoptic scale energy is benign through the periods according
to the qg vertical velocity fields. The boundary layer flow is
dominated by a weak pressure gradient through the four periods and
wind speeds are not very strong with weak normal diurnal patterns
expected. For moisture...there is quite a bit over the County Warning Area on
Monday well into the evening...before drying overnight. Tuesday
is fairly dry...with some in the middle levels for late in the day.
Tuesday night is pretty dry. There is some meager cape over the
mountains and foothills late day Monday. There is a bit more late
day Tuesday...and even some over the Western Plains. The highest
values are under 1000 j/km and over the foothills. Models show a
minor Theta-E axis over central Colorado Tuesday afternoon. There
are pretty steep lapse rates over the County Warning Area Monday afternoon. But
there is a middle level stable layer over the eastern plains. The
lapse rates are a bit steeper for Tuesday afternoon. The quantitative precipitation forecast
fields have small amounts of measurable precipitation for the
mountains Monday morning...the small amounts for the mountains and
adjacent plains Monday afternoon and evening. There is nothing
prognosticated overnight Tuesday and Tuesday morning. There is a bit of
precipitation again over the mountains...foothills and adjacent
plains for the Tuesday afternoon and evening...then nothing
tuesdaynight. For probability of precipitation...10-40%s Monday and Monday evening for
the western half of the County Warning Area...then 10-30%s for the mountains from
The Divide east into the western half of the plains late day
Tuesday. For temperatures...monday's highs are 0.5-2.0 c warmer
than today's highs. Tuesday's highs are 3-4 c warmer than
monday's. For the later days...Wednesday through Saturday...models
now show and upper ridge over Colorado Wednesday and Thursday with
a weak upper trough moving in late Thursday night into Friday
afternoon. Upper ridging returns for Friday night and Saturday.
Moisture is just fair with the trough.


Aviation...(for the tafs through 12z Monday morning)
issued at 424 am MDT sun Apr 19 2015

Showers are expected to move out of Denver early this morning with
MVFR conditions changing to VFR by 15z. North winds gusting in the
20 to 30 knot range will diminish this afternoon.


Bou watches/warnings/advisories...


Short term...gimmestad
long term...rjk

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