Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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973
FXUS65 KBOU 131627
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
927 AM MST Mon Nov 13 2017

.UPDATE...
Issued at 927 AM MST Mon Nov 13 2017

Flat upper level ridge is building over the forecast area in
moderate westerly flow aloft. 12Z Denver sounding showed a shallow
inversion and the fast warmup has already been realized across
most of the Denver Metro area with temperatures reaching the lower
60s. Afternoon highs should push 70F per the 12Z sounding, nearly
full sunshine, and continued but weak warm air advection. Overall,
winds in the high country should relax over the higher peaks,
but some breezes also push into valley locations during max
heating/mixing.

Forecast on track with only minor adjustments to sky and quick
warmup.

&&

.SHORT TERM...(Today and tonight)
Issued at 209 AM MST Mon Nov 13 2017

A relatively strong westerly flow aloft will be over the
region through tonight. The airmass will remain dry. Spatial
cross-sections so indicate the standing wave cloud over the
northeast plains will dissipate later this morning, with the
upper level cloudiness giving way to mostly sunny conditions
this afternoon. In addition, a lee side surface trough and the
presence of a weak amplified mountain wave will produce gusty
winds in the mountains and higher foothills early today. The wave
breaks down after 15z but could redevelop again tonight after 06z.
Temperatures today will be well above normal, with highs
generally in the 60s. Some fog has managed to develop over the far
eastern plains impacting primarily Phillips and Sedgwick
Counties. The models show this dissipating fairly quickly as well,
after 15z.

.LONG TERM...(Tuesday through Sunday)
Issued at 209 AM MST Mon Nov 13 2017

An upper level trough in the westerly flow aloft will track
across the Northern Rockies Tuesday. Westerly flow around the base
of the trough will bring mild temperatures and also breezy
conditions to northern Colorado. A cold front will push into
northern Colorado late Tuesday afternoon. Cooler air will move
into the area behind the front resulting in cooler temperatures
for Wednesday.

The next upper level trough will track through the intermountain
west sometime Thursday/Friday. A strong jet off the Pacific will
be associated with this system and is expected to transport
moisture across the mountains of California east to Colorado.
Models generally showing a half inch to one inch of precipitation
over the mountains with this system. Some areas may pick up a good
amount of snow Thursday/Friday. Models still having issues on the
timing of this system with the GFS showing this system moving
across Colorado 12 hours earlier than the ECWMF. There will be a
chance for light precipitation east of the mountains. The
precipitation won`t last long east of the mountains because
westerly downslope winds are expected to form behind the trough.
Highs will be mild ahead of this system Thursday with 60s over
northeast Colorado. It will cool into the 50s Friday.

For the weekend, northwest flow aloft will prevail behind the
exiting system. Temperatures are expected to remain cool for
Saturday. Models indicate ridging will be over the Central Rockies
Sunday. Temperatures will warm while dry conditions persist
through the weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 927 AM MST Mon Nov 13 2017

VFR conditions will persist with only scattered high clouds.
Generally south/southwest winds this morning at KDEN and KAPA,
then east/southeast this afternoon under 10 knots. At KBJC winds
may be more variable through the afternoon. Then winds switch to
normal south/southwest winds 01Z-03Z tonight.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Barjenbruch
SHORT TERM...Cooper
LONG TERM...Meier
AVIATION...Barjenbruch



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