Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 151040
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
340 AM MST Wed Feb 15 2017

.SHORT TERM...(Today and tonight)
Issued at 340 AM MST Wed Feb 15 2017

Large upper level ridge stretching from the Northern Rockies into
the Great Basin will slowly move east through tonight. This will
bring sunny skies and warmer temperatures. There are just a few
thin cirrus dropping over the periphery of the ridge, but not
enough to slow down any warming. While the day is starting off on
the cool side, inversions are fairly shallow and combination of
weak downslope, warm advection, and sunshine should push temps
into the lower to mid 60s over the plains, with 50s foothills, and
mid 30s through the 40s mountains. Humidities low but winds will
mostly be on the light side easing any fire danger concerns.

For tonight, look for clear skies and a dry atmosphere to allow
for strong radiational cooling again. Only exception would be
in/near the foothills with occasional downslope breezes.

.LONG TERM...(Thursday through Tuesday)
Issued at 340 AM MST Wed Feb 15 2017

Positive tilt upper ridge angled across the Desert Southwest and
central Rocky Mtn region and 700 mb temperatures around 5 deg c
over northeast Colorado would likely result in the warmest day of
the week and hardly a cloud in the sky. Model guidance offers max
temperatures on Thursday in the upper 60s and lower 70s on the
plains...and 40s to lower 50s across the high country. That means
many locales could come close to tying or even breaking their
record highs for Feb 16th. Record high at Denver now stands at 70.
See little reason to go against guidance.

By Friday...models and most ensemble members show this upper
ridge shifting east over the central Great Plains and a
strengthening southwest mid/upper-level flow over Colorado. A
weakly organized mid-level pertabation carried along by this flow
is projected to brush over Colorado Friday morning bringing with
it a batch of moisture, of which most is expected to be rung out
over the high country before reaching the plains. Even for the
high country...the chance of measurable precip is not all that
great, generally in 10-30 percent range. By afternoon, wave moves
out and drier air associated with a weak shortwave ridge moves
overhead. Could see a shift to nly sfc winds on the plains which
will slow warming. With 1-3 degs C of cooling aloft and morning
cloud cover...max temps on Friday anywhere from 5-8 degs f lower
than those the day before, but still well above average for the
date.

Over the weekend...circulation around the bottom of a deepening
upper level trough moving over California appears to drive a
couple waves of moist maritime air over the Four Corners region
and up into western Colorado on Saturday. Precip chances are
expected to gradually increase in the high country, but with
unseasonably warm temperatures, the snow level will remain high.
Areas east of the mtns will stay dry and mild. By Sunday...the
upper level trough out west is progged to close off over Arizona
and continue its southeast track over northern Mexico. By late in
the day, moisture and weak large scale lift associated with
increasing mid-level QG divergence is expected to elevate precip
chances across most of the forecast area on Sunday. The Canadian
models remains the odd man out as it shows the upper low rapidly
lifting northeast over eastern Colorado during the day which would
require going with much higher pops. Whereas the other models
keep the upper low and most of the trough moisture and energy well
to the south of the forecast area. Still a moist southerly flow
on the leading edge of the trough would presumably increase
clouds, elevate humidities, lower temperatures and give much of
the forecast area a chance of precip...with the better odds in the
high country. Warm temperatures will again keep the snow level
high, roughly up around 10,500 to 11,000 ft ASL during the day,
and precip amounts will be light.

By Monday, models show this system quickly exiting the region as
another shortwave upper ridge with warm and dry air moves in from
Utah.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 340 AM MST Wed Feb 15 2017

VFR conditions will persist. South/southwest winds will prevail
around 10 knots through 16Z. Thereafter, winds may turn more
southeasterly but some chance that it will get warm enough to
allow westerlies around 10 knots to spread across the Front Range
TAF sites 20Z-00Z. Then winds turn back to south/southwest around
10 knots by 02Z tonight.

&&

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

$$

SHORT TERM...Barjenbruch
LONG TERM...Baker
AVIATION...Barjenbruch



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