Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 280312
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
812 PM MST Sun Nov 27 2016

.UPDATE...
Issued at 657 PM MST Sun Nov 27 2016

Threat of high winds in the foothills has diminished however
still will see some gusts to 60 mph at times in a few areas
the rest of the night.

&&

.SHORT TERM...(This evening through Monday)
Issued at 205 PM MST Sun Nov 27 2016

The upper trof is already beginning to intensify across the
northern high plains while the flow aloft shifting west to
northwest over Colorado. This will improve the orographic
component over the mountains and improve snowfall potential as
snow becomes more widespread over higher mountains. Will keep the
winter hilites in the mountains. Still some concern for high winds
potential over the foothills through this evening. Cross sections
showing mountain wave developing with 40-50kt cross barrier flow
developing along with a critical level developing this evening.
There is upstream moisture over the mountains which will can
de amplify the wave and lack of large scale subsidence. With
confidence low on this wind event will leave the high wind watch
in place for now.

As for the plains...still some isolated showers on the far plains
but most of these will be gone by this evening. Dry tonight and
Monday with downslope flow in place. Occasional snow will continue
on Monday in the mountains with continued strong NW flow. Overall
snow amounts will be on the lower side of criteria but gusty
winds will still create impact on the mountain passes.

.LONG TERM...(Monday night through Sunday)
Issued at 205 PM MST Sun Nov 27 2016

Monday night into Tuesday...a strong upper level low pressure system
will track from the eastern Dakotas into central Minnesota...with a
large upper level trough of low pressure carved out across much of
the central and western United States. A moist west to northwesterly
flow aloft over the mountains...combined with cold air advection and
a few upper level disturbances will result in continued light to
moderate snow across the mountains and higher foothills. Snow
coverage and intensity should decrease Tuesday night...as moisture
and orographics diminish. However...the higher mountain peaks could
still see light snow through Wednesday afternoon.

The plains look mostly dry and breezy through wednesday due to a
downslope flow and a strong pressure gradient from west to east
across the state. However...windy conditions along with a few light
snow showers could develop over the plains east of Denver and across
the Palmer Divide Tuesday afternoon and evening due to the passage
of an upper level disturbance and associated weak cold front.

GFS and ECMWF show another upper level storm system digging into the
desert southwest by the end of the work week. The models do diverge
somewhat with the GFS being deeper with the system and shows the
upper low cutting off over eastern Nevada by 00z Friday...before
moving it into Baja Mexico by 00z Saturday.  As a result..the GFS
has more QPF over the northern and central mountains from Thursday
afternoon through Friday as lift and moisture associated with the
upper low moves across the region. In addition the GFS shows a cold
front moving into northeastern Colorado Thursday afternoon...with
upslope flow developing east of the mountains by Friday morning as
upper level high pressure builds into Colorado from the north. The
pattern would bring cloudy and cold weather along with a few light
snow showers to the Palmer Divide...Front Range Foothills and
adjacent plains if it verified. However...the ECMWF shows no such
pattern and would result in drier and slightly warmer weather. Due
to the uncertainty...will not increase pops at this time.

The upper level storm system will move across northern Mexico over
the weekend...with a drier northwesterly flow aloft setting up over
the state. This will result in warmer and drier weather across the
region...with near to slightly above normal temperatures expected by
sunday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 807 PM MST Sun Nov 27 2016

Westerly winds continue at DIA and may stay in the 15-25 mph
range through at least midnight. At some point they are supposed
to go more ssw in the 06z-08z timeframe however they could stay
generally wly the entire night.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 AM MST Tuesday for COZ033-034.

Winter Storm Warning until 5 AM MST Tuesday for COZ031.

&&

$$

UPDATE...RPK
SHORT TERM...Entrekin
LONG TERM...Kalina
AVIATION...RPK



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