Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 291859

Area Forecast Discussion
National Weather Service Grand Junction CO
1159 AM MST Tue Nov 29 2016

Issued at 1159 AM MST Tue Nov 29 2016

Have allowed remaining winter highlights to expire at noon.
Scattered light snow showers will continue in the higher
elevations with more isolated activity in the central valleys of
Colorado this afternoon. However, any additional accumulations are
expected to be spotty and relatively light.

UPDATE Issued at 848 AM MST Tue Nov 29 2016

Updated to cancel the winter weather advisories for portions of
northwest colorado and the upper colorado river valley where
snow has ended. latest models indicated that isolated showers
remain possible through the early part of the afternoon, however
additional accumulations will be light and localized. snow will
continue in the mountains of northwest and central colorado so
highlights continue in those areas.


.SHORT TERM...(Today through Wednesday)
Issued at 244 AM MST Tue Nov 29 2016

Webcams across the area show snow continuing across portions of
the forecast area this morning. These webcams across the Grand
and southern valleys including Grand Junction, Cortez, Durango,
and Pagosa Springs all show some snow accumulation on the order
of a few inches. As far as radar is concerned at this hour, some
returns can be seen but they look to be very diffuse and waning at
that. In other words, they don`t look very impressive. Infrared
satellite matches up very nicely with the snow that occurred
earlier and showed some enhancement over these areas. Now, cloud
tops look to be warming which is an indication of less lift and
thus, less precipitation. This all matches up with our very short
range models including the RAP and HRRR which show precipitation
dwindling down to very little near daybreak. The NAM12 and GFS are
a little more aggressive and keep fairly widespread, albeit light,
snowfall in the picture through most of today. With all this in
mind, will keep the warnings and advisories in place with this
mornings package.

For the remainder of the day then, on again off again showery
type precipitation for the higher terrain with some continuing
accumulations possible though not as great as seen over the last
few days. Some of the snowshowers may hit the valleys too but do
not anticipate much accumulation. Clouds will finally start to
lift as we head towards mid-afternoon and the early evening hours
except the mountains where they`ll persist.

By this evening, snow will finally end for just about the entire
CWA. The northern mountains may see some lingering snow showers
thanks to northwesterly flow and orographics but no significant
accumulations expected. Skies will clear tonight which will likely
lead to some fog for those valley locales more prone to fog

Wednesday looks to be a decent in-between day as a weak short-wave
ridge moves in. Northwest flow will continue with partly cloudy
skies expected as we wait for the next system to approach from the
northwest as early as Thursday morning. Temperatures will remain
below normal through the period.

.LONG TERM...(Wednesday through Monday)
Issued at 249 PM MST Mon Nov 28 2016

The next disturbance is expected to drop in from the northwest
Thursday through Friday, but models are not in agreement with the
details. The GFS drops the upper low circulation into Utah by
Thursday evening with southerly flow showing some enhancement in
snowfall over northeast Utah and northwest Colorado. This low then
dives south into Mexico by Friday and splits from the main trough,
leaving our CWA in the deformation zone which would limit any
significant snow at this time. The ECMWF on the other hand brings
this system across as an open wave and never splits the cutoff
low. Timing is similar in terms of precipitation with northeast
Utah and northwest Colorado being favored so kept slight chance to
chance pops in for this period due to low confidence in the
details. Dry air then works in from the northwest Friday afternoon
and evening with a ridge of high pressure building over the
eastern Pacific (just off the west coast) by the weekend. Dry
weather is expected through the weekend with the chance of precip
increasing towards Monday as another disturbance drops in from the
Pacific Northwest and moves across the northern Rockies, clipping
the northern mountains.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 244 AM MST Tue Nov 29 2016

Low ceilings and visibilities persist across the forecast area
this morning and will likely continue through much of the day.
Some showery snowfall will also likely continue especially over
the mountain TAF sites so expect ILS breakpoints to be hit for the
most of the day. Conditions will improve after about 21Z as
ceilings start to lift and most precipitation comes to an end. The
next concern then becomes fog for the overnight hours. Too far out
to include for now but something to consider as we get closer to
the overnight hours.







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