Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 170256
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
856 PM MDT Mon Oct 16 2017

.UPDATE...
Issued at 856 PM MDT Mon Oct 16 2017

Another pleasant autumn evening with mostly clear skies and mild
temps in place. Forecast on track with good radiational cooling
in the forecast given light winds in most areas and dry airmass.
Still some gusty winds expected over the mountains and higher
foothills through Tuesday, but a little weaker than today.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 230 PM MDT Mon Oct 16 2017

Colorado will remain under a light to moderate Northwest flow
aloft pattern through Tuesday. Cross sections showing the mountain
top flow decreasing a bit by this evening with overall a bit less
wind on Tuesday. Still could see some high mountain gusts up to 40
mph range through this evening. On Tuesday, gusts in the 20-30
mph look reasonable given the weaker westerly flow. Skies will
remain mostly clear/sunny through Tuesday with dry conditions but
could just a bit of high level moisture at times. Temperatures
will be slightly warmer on Tuesday.

.LONG TERM...(Tuesday night through Monday)
Issued at 230 PM MDT Mon Oct 16 2017

An anomalously warm and dry airmass coupled with a broad upper level
ridge will continue its slow eastward progression across the Rocky
Mountain region through Wednesday. Warmest 700-500mb temperatures at
during the afternoon should result in max temperatures 8-12deg F
above average for the date. This ridge shifts east of Colorado
placing the state under southwest flow aloft that is nearly as warm
as the zonal flow the day before. The shift in flow and pressure
falls east of the mtns are expected to strengthen the sly bndry
layer flow on the plains. With afternoon temperatures the 70s and
min RH values in the 15-25 pct range, the rangeland fire danger will
further increase, particularly east of a Parker-to-Sterling line.

During the same period, models show a weak mid-level shortwave
trough swinging northeast over the Four Corners area bringing with
it a batch of subtropical moisture and weak QG ascent. This feature
is progged to pass over Colorado Thursday night producing little
more than clouds, some gusty southwest winds and a few showers
largely over higher elevations. Temperatures should remain warm
enough to keep the snow level high overnight, say up around
timberline. Friday morning, this disturbance quickly exits the state
to the northeast, allowing mid-level subsidence and gusty downslope
flow to dry and warm the atmosphere, particularly east of the Front
Range. Friday temps on the plains possibly the warmest of the week
with highs in the mid to upper 70s. For the high country...models
show the start of a cool down during the day with the leading
edge of a stronger upper trough moving down from the Pacific
Northwest. Over the next 12-24 hours, this trough passes over the
Rocky Mtn region potentially resulting in a 15-20 deg F drop in
temperatures areawide. This system appears to lack moisture, but
still enough with weak QG ascent and orographic forcing to
generate scattered rain-snow showers in the high country and
isolated rain showers on the plains Friday night into Saturday.

Models remain in reasonably good agreement for the weekend as
they all show this system exiting Colorado late Saturday and a
return to dry and slightly warmer weather Sunday and Monday under
northwest flow aloft.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 856 PM MDT Mon Oct 16 2017

VFR conditions will remain in place with mostly clear skies. Light
and variable winds at KDEN and KAPA will turn to normal
south/southwest at 5-12 knots overnight. KBJC seeing slightly
stronger winds this evening but those should relax with not much
potential for mountain wave enhancement.

&&

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

$$

UPDATE...Barjenbruch
SHORT TERM...Entrekin
LONG TERM...Baker
AVIATION...Barjenbruch


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