Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 141555

Area Forecast Discussion
National Weather Service Denver/Boulder CO
955 AM MDT Fri Oct 14 2016

Issued at 955 AM MDT Fri Oct 14 2016

Increasing mid and high level moisture moving in from the west is
increasing the high level mountain wave clouds this morning. This
may limit how much warming we see today, although the warm morning
temperatures and downsloping pattern may override this. Will not
change the max temperatures at this time, but will keep an eye on
them. Have increased sky cover forecast for today however.


.SHORT TERM...(Today and tonight)
Issued at 250 AM MDT Fri Oct 14 2016

Will be close to breaking record high temperatures today. Today`s
record at Denver is 85 degrees and have a good shot of tying the
record, with an outside chance of exceeding it. 700 mb temps
again warm 5 degC east of the mountains from Thursday afternoon into
Friday afternoon, meaning surface high temperatures are expected
warm another 5-8 degrees today across the Plains, and 3-5 degrees
in the mountains. Fairly strong subsidence under the influence of
a mid- level ridge, surface lee troughing in response to moderate
westerly flow across the Rockies, and warm advection (with good
downsloping component at 700 mb) will all work in concert to
significantly warm the atmosphere today. With surface lee
troughing east of the mountains wind speeds will remain relatively
light across the urban corridor. Flow at 500 mb increases
throughout the day, and the winds at the surface will respond
accordingly in the mountains. Ridge tops/high mountains will see
winds in the 35 mph range with gusts to 50 mph. Jackson and
Larimer Counties will have the highest winds across the mountain
valleys with southwest winds 25 mph with gusts to 40 mph. No
precipitation expected across the CWA.

Tonight winds will remain strong over the mountains, especially
along the Continental Divide. Winds should stay up across the
foothills and plains immediately east of the foothills. Will be a
very warm night for those areas with downslope winds and strong
mixing. Temperatures should not cool much below the low and mid
50s west of I-25 and across most of metro Denver. Continued dry
all areas tonight.

.LONG TERM...(Saturday through Thursday)
Issued at 250 AM MDT Fri Oct 14 2016

An abnormally strong west-southwesterly upper level wind belt
slicing across the northwest CONUS early in the period will continue
to channel very dry and unseasonably warm air across the central
Rocky Mountain region through the upcoming weekend. Temperatures are
projected to run 12-17 deg f above average for mid-October across
the CWA with the warmest readings as usual along the base of the
Front Range foothills the product downslope adiabatic heating and in
lower areas downstream along the South Platte River. Do not expect
to see much in the way of cloud cover over the weekend except
perhaps bands of high altitude cirrus/cirrostratus whisked along by
the swift flow aloft.

By Monday...the aforementioned river of strong swly winds aloft is
progged by most models to shift southward over Colorado. Strong
heights falls and a cold pool aloft upstream over nrn Nevada/srn
Idaho Sunday night are forecast to translate eastward over
Wyoming and nwrn Colorado by Monday morning. This serves to
enhance baroclinicity acrs Wyoming through the day. Models show
strong momentum mixing downward resulting in gusty west/northwest
sfc winds behind a strong cold front which the GFS...ECMWF...DGEX
and Canadian models show advancing across the nrn central mtns of
Colorado Monday afternoon and out across the nern plains of the
state during the evening. The front appears to outrun any upper
air support and appreciable moisture...although the higher
elevations in the north cntrl mtn ranges could see showers
developing due in part to orographic forcing during the afternoon.
QPF amounts are still forecast to be on the light side. On the
plains could see nwly post-frontal winds gusting in the 35-45 mph
range Monday evening. Fortunately at the same time sfc dewpoints
should be on the rise as temperatures begin their nose dive.

By Tuesday...models show a broad upper trough stretched acrs the
northwest and north central CONUS as the strong Pacific Jet
continues to sack southward. Models show the 500 mb trough axis
passing over Colorado by late in the day. The bulk of the large
scale energy and moisture appears to remain well north of
Colorado even while cooler air continues to stream in from the
north. Highs on Tuesday are projected to be 15-18 deg f lower than
those the day before with the most notable collapse in
temperatures east of the mtns. The influx of colder air Monday
night and Tuesday will lower temperatures to about where they
should be this time of year. The new airmass looks pretty dry
although late on Tuesday the GFS and Canadian GEM indicate pockets
of light QPF on the plains with several hours of enhanced
anticyclonic upslope flow. That said...will stick in low pops
over and along the Front Range Tuesday evening and across the
nern corner of the CWA later in the night with passage of a small
bundle of mid-level energy.

By Wednesday...most of the moisture moves east with the deepening
upper trough over the Great Plains. Amplification of the trough
turns the flow aloft more northwesterly which will continue to
draw slightly cooler air down from the north. Could see a few deg
drop in temperatures on Wednesday and another deg or two on
Thursday. Still temps will be near to slightly below average. This
period looks dry. By Friday...guidance indicates a several deg
rebound in temperatures as a high amplitude upper ridge approaches
from the Great Basin. Still no sign of measurable precipitation
or for that matter any measurable snowfall for the high country.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 955 AM MDT Fri Oct 14 2016

VFR expected today, tonight, and tomorrow. Enhanced drainage
winds should subside to 10 kts or less by 17Z. Wind direction
continues to be a challenge at all the airports due to the
position of the surface trough along the front range urban
corridor. For the same reason winds should be on the light side until
drainage winds kick in around 02Z. Drainage winds will again be
enhanced overnight as the surface trough remains.


Issued at 250 AM MDT Fri Oct 14 2016

On Friday we expect an elevated fire danger across parts of the
CWA. It will be near-record warm across eastern Colorado.
Depending on on where you look, one or two ingredients will be
high but it does not look like all required ingredients will come
together to meet or exceed criteria levels. Across Lincoln,
Elbert, and Washington Counties, relative humidity will bottom out
near 10 percent Friday afternoon. Winds will be in the 15-20 mph
range. The rest of the dry lower elevations across the Plains will
also have low RH but winds will remain lighter due to the
influence of surface lee troughing. The other area of concern
Friday is across Jackson and western Larimer Counties. Winds for
several hours Friday afternoon could be 25 mph gusting to 35 but
RH should be around 20 percent. All this to say that fire danger
will be elevated.

Fire weather conditions look to remain elevated Sunday and Monday
afternoons, primarily across Park County and the north slope of
the Palmer Divide. Winds are not expected to be strong enough to
reach criteria levels.




SHORT TERM...Schlatter
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