Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 160347

Area Forecast Discussion
National Weather Service Denver/Boulder CO
947 PM MDT Sat Oct 15 2016

Issued at 947 PM MDT Sat Oct 15 2016

Only minor changes this evening, chiefly to delay the onset of
stronger winds over the higher mountains. We are in a little
shortwave ridge at this time with a speed minima in the low/mid
levels. Expect that the stronger winds will not really come until
morning. Also fewer clouds due to the same ridging. We should have
a wave cloud developing with the increasing winds around sunrise.


.SHORT TERM...(This evening through Sunday)
Issued at 223 PM MDT Sat Oct 15 2016

A strong southwesterly flow aloft will be over the region this
overnight. A dry and stable airmass will be in place overnight
with mild temperatures again expected in and near the foothills.
Gusty winds again expected there...strongest after midnight. NAM12
spatial cross-sections show cross mtn component of 50 kts around
650 mb. To amplified mountain wave present so suspect stronger
winds will be above timberline...but could see gusts 35-40 mph in
the foothills.  On Sunday...strong southwesterly flow will remain
over the cwa through the day. Very mild temperatures in the mid
80s should not be able to break the record of 89. Strong winds in
the mountains and foothills again will elevate the fire danger so
have upgraded the fire weather highlights for Sunday...see the
fire weather discussion below.

.LONG TERM...(Sunday night through Saturday)
Issued at 300 PM MDT Sat Oct 15 2016

A powerful Pacific jet stream will plow into the Central Rockies
Sunday night. Mid level flow will strengthen considerably with
both the NAM and GFS showing 80 knots mean flow at 600 mb. Looks
like a brute force type of event over the higher Front Range
mountains down to the higher peaks in Summit County where gusts up
to 85 mph or more possible. Fortunately, there is not a
significant mountain top stable layer so the strongest winds
should be confined to the higher elevations.

On Monday, an increasing pressure gradient combined with a cold
frontal passage toward mid day will help the stronger winds
spread down the Front Range and across the plains. At this time,
don`t see a high wind threat as the strongest downward forcing in
the QG fields is across eastern Wyoming. There is still a moderate
surface pressure gradient, very strong flow aloft, and good
mixing, so will continue to monitor. Have beefed up the winds
with potential for 40-50 mph gusts across the plains Monday
afternoon into the evening. The strong winds and only slight
cooling will lead to high fire danger across the foothills and
plains...see fire weather discussion section below.

Tuesday will feature cooler temperatures and lighter winds. There
should be some precipitation chance developing in the afternoon or
evening with approach of the next short wave. Not sure if this
energy will come in one or two pieces at this point, but appears
the chance of light precipitation will remain in the forecast
through Wednesday in colder northwest flow aloft. There is now
reasonable agreement between the GFS, ECMWF, and Canadian
regarding the weak upslope, moisture, and depth of the approaching
short wave. Will increase PoPs a bit more for this period.
Temperatures are still advertised to be cold enough for a chance
of snow down into the lower elevations by late Wednesday/Wednesday

After that disturbance passes by, it looks like we`ll gradually
return to dry and warmer weather again for Friday into next
weekend as a large ridge pops up over the western U.S.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 947 PM MDT Sat Oct 15 2016

VFR through Sunday. S/W drainage winds the rest of the night, with
some increase possibly by 12z, especially at KBJC. There is a
chance of strong west winds in the 20-30 knot range at KDEN Sunday
afternoon. If this happens it is not expected to last for a long
time, most likely a few hours in the mid to late afternoon. There
is a lower risk of this at KAPA, while KBJC will likely see west
winds gusting over 20 knots much of the day and to 30 knots at


Issued at 223 PM MDT Sat Oct 15 2016

Mild temperatures overnight with gusty winds will limit the rh
recovery overnight. Strongest winds tonight in the foothills will
be after midnight. Main concern will be on Sunday. Strong
southwesterly winds again expected with continued warm
temperatures. Upgraded the Fire Weather Watch to a Red Flag
Warning and expanded it to also include fire weather zones
213..215..238 and 239 for late Sunday morning into early Sunday

Winds will strengthen further on Monday as a powerful Pacific jet
stream pushes into the Central Rockies. There should be a few
degrees of cooling but the stronger and more widespread winds
developing in the wake of a cold front will offset that,
especially on the plains with increasing grassland fire danger.
Have issued a fire weather watch for that threat on Monday. Winds
may last well into the evening so ran watch til 9 PM for now.


Fire Weather Watch from Monday morning through Monday evening
for COZ214>216-238>251.

Red Flag Warning from 11 AM to 7 PM MDT Sunday for COZ213>216-

High Wind Watch from Sunday evening through Monday evening for



LONG TERM...Barjenbruch
FIRE WEATHER...Cooper/Barjenbruch is the U.S. government's official web portal to all federal, state and local government web resources and services.