Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 142032
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
232 PM MDT Sat Oct 14 2017

.SHORT TERM...(This evening through Sunday)
Issued at 232 PM MDT Sat Oct 14 2017

For the remainder of this afternoon, passage of an
upper trough and shift to a swift northwest flow aloft
coupled with strong mid-level subsidence will crank up
north-northwest sfc wind speeds on the plains for the next
few hours. Strongest winds will be up along the Cheyenne
Ridge in Larimer and Weld Counties and out across the
northeast corner of the state. Speeds in the 30-50 mph range
through 23z today. Then a gradual drop off in speed
everywhere with subsidence weakening as the upper trough
races east of the forecast area.

In the high country...a band of moderate snowfall generated by
a strong jet on leading edge of upper trough now over nrn
Colorado. Mtn CAMs show the bulk of this snowfall concentrated
over the mtn ridges and high passes north of Interstate 70. Could
see snowfall intensity pick up during the next couple of hours as
cold air advection kicks in with the passing 700 mb trough axis.
Could see a couple inches of snow above timberline and higher west
slopes in Jackson, Grand and Larimer counties. Otherwise dry
elsewhere.

Tonight...will see drying both sfc and aloft over the area once
the 700-500mb trough passes by. As a result should see the last of
the snow shower activity in the high country come to an end early
this evening. Will also see a steady drop off in wind speeds on
the plains and and a shift to their typical drainage pattern by
mid to late evening with decoupling of the boundary layer
from the 50-80kt west-northwest flow aloft. However, the higher
mtn ridges and upper east slopes of the front range will likely
remain windy overnight with gusts in the 30-50 mph in exposed
areas. A clear sky, drier air and light breezes will lead to
another night of sub-freezing temperatures at lower elevations.

On Sunday...the swift flow aloft becomes northwesterly and dries
out even more in response to an upper ridge building over the
Great Basin. Skies generally clear tomorrow and winds no where as
strong/gusty. Even high mountain locals should see a gradual
reduction in wind speeds during the afternoon with the core of
strongest winds aloft migrating northward over Wyoming. Highs
tomorrow generally 4-8 degs above those today, but readings still
a few degrees below average for the date.

.LONG TERM...(Sunday night through Saturday)
Issued at 232 PM MDT Sat Oct 14 2017

Flat upper level ridge will build over the Central Rockies for
much of this upcoming week. Temperatures will warm to above normal
levels Monday, and daytime highs should average about 8-10 degrees
above normal through Friday. Maybe a weak backdoor cold front
Wednesday but don`t see much cooling at this point.

Dry conditions will prevail until next trough approaches. This
occurs late Friday into Saturday according to the GFS, although
if trough digs into the southwest more as the ECMWF indicates
precipitation chances and cooler weather may not arrive until
Saturday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 232 PM MDT Sat Oct 14 2017

Gusty north/northeast winds of 30-42 kts at Denver area air
terminals are expected to gradually weaken at first around 23z
this afternoon, then at a faster pace early this evening and turn
northeast in direction. By mid-evening, should see winds in the
metro assume their typical nighttime drainage pattern, with a
south- southwest wind of 5-10 kts at KDEN and KAPA, and west-
southwest of 7-14 kts at KBJC. Speeds may drop off further after
midnight. On Sunday...look for light southerly breezes in the
morning will become light easterly in the afternoon under a clear
sky.

&&

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

$$

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



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