Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 240303

Area Forecast Discussion
National Weather Service Denver/Boulder CO
903 PM MDT Sun Oct 23 2016

Issued at 900 PM MDT Sun Oct 23 2016

Tranquil weather conditions dominate the fcst region this evening
beneath an upper level ridge and light zonal flow aloft. As this
ridge slowly migrates eastward overnight should see winds aloft
turn southwesterly. High-level moisture upstream over Utah will
also gradually spread eastward over northwest Colorado overnight...
potentially reaching northwest corner of the forecast area...i.e.
Jackson...Grand and western Larimer counties by morning...if not a
few hours sooner than that. Do not expect to see any precipitation
with this advancing cloud cover. Otherwise it will continue dry
and mild elsewhere with the usual nocturnal drainage wind set up.
Made minimal adjustments to the forecast grids this evening.


.SHORT TERM...(This evening through Monday)
Issued at 126 PM MDT Sun Oct 23 2016

Upper ridge remains over the area through Monday. Some high
clouds streaming over but mainly thin tonight, then thickening
from west to east on Monday. Expect the clouds to have a slight
effect on temperatures, combining with a little wind on the plains
to keep it mild tonight, and restraining highs a couple degrees on
Monday. With slightly warmer air off the ground, temperatures
should still get to near what we have this afternoon. With the
low/mid level air moistening a little from the west there could be
just enough instability for a few light showers over the mountains
in the late afternoon. More likely they will wait for evening.

.LONG TERM...(Monday night through Sunday)
Issued at 126 PM MDT Sun Oct 23 2016

There is southwesterly flow aloft Monday night, then a weak upper
trough moves across the CWA early Tuesday. West-northwesterly
flow aloft is progged from late Tuesday afternoon well into Wednesday
with an upper ridge to be over Colorado Wednesday night. The QG
Omega fields have weak upward energy for the CWA Monday night into
midday Tuesday, then weak downward motion is in place through
Wednesday night. The boundary layer winds are mostly normal
diurnal trends Monday night and Tuesday. There is northwesterly
downslope progged much of Tuesday night and southeasterlies
Wednesday. Moisture-wise, models seem to have a bit more with the
Monday night/Tuesday upper trough than the last model runs
indicated. The moisture is fairly deep in the mountains and there
is no low level moisture over the downsloping plains. By Tuesday
afternoon there is decent drying. Tuesday night through Wednesday
night look pretty dry. The Qpf fields had some measurable
precipitation Monday night and Tuesday, but it is mostly in the
mountains. Tuesday night through Wednesday night are dry. For pops
will go with 40-70%s in the mountains Monday night into mid day
Tuesday. There will be lesser pops for the foothills and maybe
10%s for the immediate plains. For temperatures, Tuesday`s highs
are 1.0-2.5 C colder than Monday`s. Wednesday`s highs are close
to Tuesday`s. For the later day`s, Thursday through Sunday, models
have the upper ridge in place for the CWA Thursday into Friday.
The ECMWF hints at a weak upper trough late Friday into Saturday,
the GFS does not. The GFs has a weak upper trough Saturday
afternoon and night, the ECMWF doe snot. Both have an upper ridge
on Sunday. Will keep things dry much of the time, with just a tad
of alpine pops Friday night and Saturday. Temperatures stay warm.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 900 PM MDT Sun Oct 23 2016

The usual nocturnal drainage wind pattern has setup across the
Denver metro area at this hour. Would expect little change in
this wind configuration for the remainder of the night. Speeds for
most of the Denver metro area should remain under 12 kts...although
the HRRR and RAP indicate a band of stronger southerly winds
across the southeast corner of the metro area between 05z -09z
tonight. Speeds in this area may be as much as 3-6 kts
greater...with speeds not expected to be more than 20 kts during
this 4-hour period. Overwise...should see a gradual increase in
cirrus overnight as high-level moisture continues to feed in from
the west and through the lee slope mountain wave.




SHORT TERM...Gimmestad
AVIATION...Baker is the U.S. government's official web portal to all federal, state and local government web resources and services.