Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Denver/Boulder Colorado
1028 am MDT sun Mar 16 2014
Update...cloud band finally exiting the northeast corner of the
state. Sunny skies on tap through the afternoon with only a few
cirrus clouds. Temperature forecast on track.
Winds and even lower humidity expected for Monday...so issued a
red flag warning for the northeast plains and Palmer Divide area
where fuels are driest.
Aviation...north wind development likely delayed a couple hours
as boundary layer is a little cool. Still think northwesterlies
will develop later this afternoon as daytime heating contributes
to better mixing...with a few gusts around 20 kts possible 21z-
Previous discussion... /issued 405 am MDT sun Mar 16 2014/
Short term...dry northwesterly flow aloft will be over the area today and
then become more west-northwest tonight. Winds will be lighter today but
still may see a few gusts to 30 miles per hour over the plains this afternoon.
Overall highs should be in the 55 to 60 degree range over northestern Colorado.
Tonight winds will increase in the mountains and foothills with component
along flow in the 35-40 knots range. Thus may see gusts from 50 to 60
miles per hour developing after midnight.
Long term...northwesterly flow aloft becomes zonal through the
day Monday. An upper trough moves into Colorado late in the
day...it's axis pushes east across our County Warning Area around 12z Tuesday
morning. The European model (ecmwf) is slowest. On Tuesday the flow aloft is west-
northwesterly. Models have another...weaker upper trough move into
western Colorado by 12z Wednesday morning. The qg vertical
velocity fields have fairly decent upward synoptic scale energy on
Monday...then pretty strong downward motion Monday night and
Tuesday. By Tuesday night...weak downward motion is prognosticated. The
boundary layer flow is dominated by southwesterly downsloping
Monday morning...then westerly downsloping for the afternoon. A
cold front moves into the County Warning Area from the northwest around 00z late
Monday afternoon. Northwesterly downsloping is prognosticated Monday
night at fairly brisk speeds...then north-northwesterly on
Tuesday. By Tuesday night...the wind field should be a mix of
normal drainage patterns and a bit of downsloping mixed in. For
moisture...Monday starts out pretty dry...but then cloudiness
increases through the day from the west. On Monday night...
moisture is fairly deep over the mountains...with the eastern County Warning Area
getting some by Tuesday morning. There is some moisture around
Tuesday...but nothing significant. The quantitative precipitation forecast fields have a tad of
measurable precipitation over the mountains Monday afternoon into
Tuesday evening. Amounts are limited. There is very little
indicated on any of the models over the plains through that
period. For probability of precipitation will keep the 50-70%s in the high mountains
Monday night and Tuesday...with only "slight chance"s over the
plains. No highlights right now. As previous shift indicated...the
wind and dryness could create a fire weather highlight over the
northeast corner Monday afternoon/early evening. For
temperatures...monday's highs are 2-5 c warmer than today's.
Tuesday's highs are 7 to 12 c colder than monday's. For the later
days...Wednesday through Saturday...models have a weak upper
trough move across the County Warning Area Wednesday morning...then zonal flow is
prognosticated the rest of Wednesday and Thursday. For Friday and
Saturday...there is west-southwesterly flow aloft for the
County Warning Area...with just enough moisture in the mountains for low probability of precipitation.
Aviation...drainage winds early this morning will become northerly by
late morning and continue through the afternoon with speeds in the 10-15
miles per hour range although could see a few gusts to 20 miles per hour at times in the
21z-00z time period. Winds early this evening will become light
northwesterly and then shift gradually back to drainage after 03z.
red flag warning from noon to 8 PM MDT Monday for coz241-242-