Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 231207

Area Forecast Discussion
National Weather Service Denver/Boulder CO
507 AM MST Thu Feb 23 2017

.SHORT TERM...(Today and tonight)
Issued at 507 AM MST Thu Feb 23 2017

Upper trough over Utah sliding east with large area of synoptic
scale lift from NE Utah/NW Colorado across Wyoming. This will
bring increasing snow to the mountains today, spreading along the
northern Colorado border as well. The strongest lift will be
north of the border, but with a sustained period of light to
moderate snow there should be an area of 1-3 inches of snow north
of about Fort Collins to Sterling and perhaps even more at the
state line. We will have to monitor just where this sharp gradient
winds up. The area of showers further south over SE Utah/SW
Colorado will eventually move over the central mountains and
should bring a round of snow showers across Denver in the late
afternoon and evening. This will be at the same time that north
winds will be increasing behind the surface low with cooling
temperatures. While the ground is warm to start the day, cool air
will remain in place so an inch or two of snow this evening could
still be enough to cause some travel issues around Denver.

Changes to the forecast include a general increase in PoPs as
confidence increases, with slight increases to the snowfall as
well, and adjustments to the timing mentioned above.

.LONG TERM...(Friday through Wednesday)
Issued at 507 AM MST Thu Feb 23 2017

Models have a mean upper trough over the western United States on
Friday. Flat upper ridging is over Colorado Friday night and
Saturday. Southwesterly flow aloft is progged Saturday night with
another upper trough to our west. The synoptic scale energy is
mostly downward in nature from Friday midday through Saturday
evening. For moisture, Friday looks cloudy. Moisture decreases
significantly across the CWA Friday night. On Saturday morning,
there is a tad lingering over the mountains. Later Saturday,
moisture increases substantially from the west. It is deep in the
mountains, with plenty in the mid and upper levels for the
plains. Models show Saturday night the same. The QPF fields have a
tad of measurable precipitation over the mountains Friday and
Friday evening, then again from later Saturday afternoon and
Saturday night. There is tiny bit progged over the plains Friday
morning into the early afternoon hours. For pops in the mountains,
will go with "likely"s early Friday, then "chance"s in the
afternoon and Friday evening. Will decrease pops to nothing early
Saturday, then increase them again by Saturday afternoon and night
to "chance"s. Snowfall amounts will be minimal. For the plains,
will go with "chance"s for snow Friday morning, then "slight
chance"s Friday afternoon, then dry after that. For temperatures,
Friday`s highs are 2-5 C colder than today`s highs. Saturday`s
highs only warm up 1-4 C over Friday`s highs. For the later days,
Sunday through Wednesday, models have a weak upper trough to push
across Colorado on Sunday. There is zonal flow aloft Sunday night
through Tuesday morning, then another upper trough moves across
through Wednesday morning. There is northwesterly flow aloft after
that. Sunday is pretty dry, but moisture increases Sunday night
with fair amounts in the mountains through Tuesday night.
Wednesday dries out. Temperature progs are not as warm on these
latest 00Z model runs as they were on yesterday`s for all four


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 507 AM MST Thu Feb 23 2017

Low clouds will persist in the Denver area this morning. There may
even be some patchy freezing drizzle, though it is not expected to
be enough to accumulate. MVFR ceilings with isolated IFR is
expected through 18z. Some improvement is expected by midday with
some breaks in the low clouds possible, but then snow showers will
develop after 21z with MVFR conditions prevailing again. For
tonight, MVFR conditions in snow showers are expected to prevail
with localized IFR conditions at times. Snowfall in the Denver
area is expected to be an inch or two.


Winter Weather Advisory until 9 AM MST Friday for COZ031-033.



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