Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 180135
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
735 PM MDT Tue Apr 17 2018

.UPDATE...
Issued at 735 PM MDT Tue Apr 17 2018

Increased coverage of snowfall for the central Colorado mountains
early this evening as latest observations and radar imagery in
good agreement with latest model QPF output. Additionally, ended
the Wind Advisory for the Gunnison Basin early as winds have
decreased below criteria and will continue to decline during the
night.

&&

.SHORT TERM...(Tonight through Wednesday night)
Issued at 355 PM MDT Tue Apr 17 2018

Scattered showers in the wake of the cold front will continue
through the evening hours across the northern and central Colorado
mountains. The breezy to gusty conditions that have been experienced
across the region today will cease overnight, and skies will
clear as a ridge of high pressure builds in from the west. The
combination of light winds and radiational cooling will lead to
below freezing temperatures across almost all valley floors.
Reports of budding fruit trees around the Paonia, Dove Creek, and
Cortez areas has prompted the expansion of the Freeze Warning to
include those areas.

Temperatures return to near seasonal levels on Wednesday as the
ridge of high pressure traverses the region resulting in light winds
and sunny skies. Winds will become breezy from the south- southwest
Wednesday night ahead of a strong upper level closed low over
Nevada. More to come on this system below.

.LONG TERM...(Thursday through Tuesday)
Issued at 355 PM MDT Tue Apr 17 2018

The nice weather we had on Wednesday will slowly deteriorate
Thursday as the next system approaches from the west. By Thursday
morning, a closed low will be over the Great Basin and is still
on track to continue deepening as it moves into our area. Before
that happens though, the pressure gradient will tighten ahead of
the low. While winds don`t look as strong as what we`ve seen
lately, they`ll likely gust from the 25 to 35 mph range...maybe
a bit higher from time to time. Humidities will remain low and
with continued dry fuels in place, critical fire weather
conditions look likely once again. More info below on that. Aside
from that, expect clouds to be on the increase as temperatures
reach into the 70s for many valley locations.

As the low continues to get closer to the area, wind flow looks to
pick up some moisture from the south. Unfortunately, the GFS is
showing all this moisture to stream up into the Front Range and
areas east while we continue to remain relatively dry. The Euro
has different thoughts, however. The EC puts much of western
Colorado in a relatively large area of precipitation that persist
from Friday morning through late Friday night. The Canadian starts
precip late Thursday night and also puts more precip on the
Western Slope than the GFS. We`ll all be waiting for the next few
model runs to see how this plays out.

By Friday evening, the low will be moving into the Front Range and
will then bring some wraparound moisture into our CWA. This phase
of the storm will favor the northern and central mountains as well
as the northern valleys. QPF amounts look to be fairly high as the
moisture that moved in from the south gets pulled into our area
thanks to cyclonic flow. Amounts appear somewhat suspect because
this flow normally causes upslope over the Front Range and more
precip there. Again, something else we`ll be watching.

By Saturday night, precip ends as a weak transitory ridge passes
overhead. A low amplitude trough will then approach from the west
and may cause a few showers Sunday evening over the higher
terrain. Guidance not sure what to do with this trough, close it
off...keep it open and shift eastward, so chance PoPs for the
Monday & Tuesday timeframe looks best.

Temperatures Friday will be well below norms but will quickly
spring back into the 60s and 70s Saturday onwards.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 735 PM MDT Tue Apr 17 2018

The last vestiges of the storm which moved through the area
earlier today will continue to bring snow to the central Colorado
mountains early this evening. As a result, KASE and KEGE will have
CIGS below ILS breakpoints through 04Z. In addition, KASE will
continue to experience moderate snow resulting in periods of VLIFR
visibility and LIFR CIGS. Conditions improve after 04Z with both
KASE and KEGE improving to VFR conditions. Remaining TAF sites
will have VFR conditions throughout the next 24 hours. Meanwhile,
strong and gusty west to northwest winds will diminish overnight.

&&

.FIRE WEATHER...
Issued at 355 PM MDT Tue Apr 17 2018

The next storm system to affect our weather will first bring some
gusty winds to the region on Thursday as the surface pressure
gradient tightens. Wind gusts should generally range from the 25
to 35 mph range while humidities drop to the single digits and low
teens. Dry fuels remain so we can expect another day of critical
fire weather conditions. According to our partners, critical fuels
have now been noted in zones 200 west of Maybell and zone 202
west of Meeker and have been included in this Fire Weather Watch.
Remaining zones include Colorado Fire Zones 290, 207, and 203
below 6000 feet and 295 below 8000 feet. As will be the case until
we get some rain, open burning is highly discouraged under these
conditions as any fire starts will be difficult, if not
impossible, to contain.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Freeze Warning from midnight tonight to 9 AM MDT Wednesday for
     COZ006-011-020-021.

     Fire Weather Watch from Thursday afternoon through Thursday
     evening for COZ200-202-203-207-290-295.

UT...Freeze Warning from midnight tonight to 9 AM MDT Wednesday for
     UTZ022-027-029.

&&

$$

UPDATE...NL
SHORT TERM...JPF
LONG TERM...TGR
AVIATION...NL
FIRE WEATHER...TGR



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