Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

FXUS65 KGJT 181736

Area Forecast Discussion
National Weather Service Grand Junction CO
1136 AM MDT Sat Mar 18 2017

.SHORT TERM...(Today through Sunday)
Issued at 324 AM MDT Sat Mar 18 2017

Broad high pressure will remain over the area today and tonight.
Record warmth will repeat again today with dry conditions leading
to no chance of precipitation. The 500 mb ridgeline will slide
east of the area by sunset today with SW flow aloft spreading over
the area ahead of a strong Pacific storm system.

On Sunday SW winds aloft will continue to increase along with high
clouds ahead of the next storm. Temperatures will only lose 1 or 2
degrees, mainly over north where more cloud cover is expected. As
the pressure gradient increases gusty wind will be more prevalent
in the afternoon.

.LONG TERM...(Sunday night through Friday) Issued at 320 PM MDT
Fri Mar 17 2017

Mid to upper level cloud cover will increase Sunday night as the
pattern shifts to a cloudier and eventually wetter pattern. The
previous forecast discussion mentioning Sunday showers over the
mountains already looks to be outdated as the first threat of
precip shifts back to Monday. Even on Monday, mountain showers
will be isolated and very much terrain driven with weak embedded
energy over the ridge axis. The GFS is most bullish on precip on
Monday evening, and is an outlier at this point.

Clouds will stick around Tuesday, but the next chance of
precipitation is with the approaching system midweek on Wednesday.
The GFS, EC, CMC are still dancing around with their details, but do
still indicate precip beginning Wednesday evening sometime favoring
areas in southwest flow. The GFS continues to develop a closed low
over Utah before tracking it into Colorado on Thursday, versus the
EC and CMC which keep this system as an open wave. Available
moisture for this system even more impressive today than what we saw
the last couple of days, which indicates a warmer system. The
mountains of eastern Utah and western Colorado could receive a
significant amount of snow (above ~9000 ft, maybe even higher), with
liquid equivalence in either rain or snow form adding some
significant moisture to the region. QPFs on the GFS are indicating
about an inch of liquid precip in mainly locations, so we will need
to watch not only new snowfall, but rain on snow issues as well. As
mentioned in previous discussions, the snow level behind the
associated cold front may drop low enough for valleys above 6000 ft
on Thursday to see some snow at times, but these detailed can`t be
accurately parsed out until we get some forecast model consensus
and figure out the strength of this system.

This weather system will impact the region Wednesday through
Thursday, with conditions looking to clear Friday and Saturday
before the next chance of precipitation next Sunday with another
open trough or closed low.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1135 AM MDT Sat Mar 18 2017

Minimal to no impact can be anticipated at area forecast
terminals over the next 24 hours. Some mountain and valley breezes
are expected during the heating of the day and this could lead to
occasional gusts near 25 mph at KEGE.


Issued at 324 AM MDT Sat Mar 18 2017

High pressure flattens over the area today. This will allow
southwest winds to strengthen over the region by Sunday afternoon.
Relative humidities are expected to drop into the 15 to 25
percent range Sunday afternoon, but may drop lower with record or
near record heat persisting. The gusty winds combined with warm
temperatures, low humidity and still dormant or dry vegetation
will require a heightened fire weather awareness. Check the
latest forecast before attempting any burning through this weekend
as conditions can change rapidly. The potential will be greatest
for elevations below 8000 feet.


Issued at 324 AM MDT Sat Mar 18 2017

Prolonged period of record or near record high temperatures will
continue to impact the region through Sunday. This will
accelerate snowmelt resulting in increased flows on area waterways
and slow but steady rises in river levels. Temperatures are
expected to cool next week, which will help to slow the snowmelt,
however major moisture is possible during the middle of next week
in the form of both rain and snow. Will need to monitor for rain
on snow issues that could develop mid to late next week with the
changing snowpack levels.





FIRE WEATHER...TGJT is the U.S. government's official web portal to all federal, state and local government web resources and services.