Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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864
FXUS65 KBOU 140354
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
854 PM MST Fri Jan 13 2017

.UPDATE...
Issued at 840 PM MST Fri Jan 13 2017

Satellite imagery showing increased moisture over the southern
and SE portions of the CWA as the low over Southern CA continues
to bring southerly flow. This will keep mostly cloudy conditions
over the mountains and southern portions of the state. Areas on
the plains are seeing clear to scattered conditions currently with
moist low levels that could result in patchy fog...especially
over areas of the South Platte south into Northern Lincoln county.
I left it out of the grids for now due to low confidence given
increasing mid level clouds and any lack of precipitation today.
Some reduced vis could be possible due to haze however during the
early morning hours. In the mountains mostly cloudy conditions
will prevail in the high valleys so had to increase overnight lows
in those areas to account for the lack of radiational cooling.
Otherwise forecast is on track at this time.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 100 PM MST Fri Jan 13 2017

Upper low over Southern California Coast with a continued
southwest flow aloft over Colorado. There is considerable middle
and high level moisture in the flow which will keep the skies
partly to mostly cloudy for much of the mountains and lower
elevations. Given the light Southwest orographic flow and shallow
moisture depth, will keep scattered snow showers going in the
mountains but any additional snow accumulations will only range from
Trace amounts up to 2 inches by late Saturday. Exiting jet streak
over northern colorado will enhance the light snow a bit this
evening over far Western/Northern Colorado. Across lower
elevations will keep fog out of the forecast given the continued
swath of mid/high level cloud cover.

.LONG TERM...(Saturday night through Friday)
Issued at 100 PM MST Fri Jan 13 2017

Moderately strong southwesterly flow aloft is progged Saturday
night for the CWA. Models have an upper closed circulation over
the northeastern corner of Sonora, Mexico at 12Z Sunday morning.
This feature pushes east-northeastward in southeastern New Mexico
at 00Z sunday afternoon late. By 12Z Monday morning, it is located
anywhere from the Texas Panhandle to southwestern Kansas,
depending on the model. The flow aloft is south-southwesterly
Sunday into early Monday morning and decreasing. By later Monday
afternoon, north-northeasterly flow aloft is over the CWA
continuing Monday night. The QG Omega fields have weak upward
vertical velocity for the CWA Saturday night into Monday morning.
After that, weak downward motion is in place through Monday
night. The boundary layer winds will be weak and Sunday and Sunday
evening. After 06Z Sunday night models have a cold front and some
stronger northerly winds for the plains. On Monday, strong north-
northwesterly winds are progged. For moisture, it gradually
increases from south and southwest to north Saturday night into
Sunday. Fairly deep moisture is in place for much of the CWA
later Sunday afternoon into Monday morning. Moisture decreases
later Monday and Monday night. The QPF fields show no measurable
precipitation Saturday night. There is limited measurable
precipitation for the CWA SUnday into Monday afternoon, with the
best amounts over the southeastern half of the CWA. For pops, will
get them up to "likely"s from Sunday 18Z to 18Z Monday. That will
be only for the southern and southeastern CWA. The best pops for
snow will be Sunday night. Soundings still show chances for
freezing drizzle and maybe sleet over the southeastern and
eastern CWA early Sunday morning and Sunday day. None of the
precipitation amounts look close to highlight criteria amounts at
this time. For temperatures, Sunday`s highs are close to
Saturday`s. Monday`s highs will be 2-4 C cooler than Sunday`s.
For the later days, Tuesday through Friday, upper ridging is
progged into Colorado Tuesday into Wednesday. The flow aloft is
weak an northerly, then northwesterly into Wednesday morning.
Southwesterly flow aloft kicks through Thursday night, with an
upper level trough to move across the CWA Friday into Friday
evening. Will get some snow in the mountains from Wednesday night
into Friday. Will need pops in for the plains on Friday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 840 PM MST Fri Jan 13 2017

VFR conditions are expected for the next 24 hours. A high level
BKN deck will prevail through most of the TAF period. Winds will
be light and variable through the evening switching to drainage
overnight then turning variable before becoming NE around 21z
tomorrow afternoon. For Saturday night into Sunday an inverted
trough over the state will help to usher in southerly winds
Saturday night with increasing moisture.

&&

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

$$

UPDATE...Bowen
SHORT TERM...Entrekin
LONG TERM...RJK
AVIATION...Bowen



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