Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 240925

Area Forecast Discussion
National Weather Service Grand Junction CO
325 AM MDT Thu May 24 2018

.SHORT TERM...(Today through Friday)
Issued at 325 AM MDT Thu May 24 2018

Drier westerly flow will occur today as the ridge of high pressure
amplifies over the Desert Southwest and builds further north
across the region. Some lingering moisture will remain up north,
closer to the Wyoming border, with enough instability to trigger
afternoon thunderstorms among the higher terrain. The best chance
looks to be over the eastern Uintas today as a weak embedded
shortwave moving north of the region may help trigger something.
Other than the eastern Uintas, really not expecting much in the
way of storm activity given the much drier atmosphere and overall
lack of forcing across western Colorado. This will lead to mostly
sunny skies and temperatures warming to almost 10 degrees above
normal. Leaning towards the warmer end of guidance given the lack
of cloud cover and shower activity with H7 temps rising to the 10C
to 12C range. This means mid to upper 80s for most lower valleys
and temps approaching low 90s for southeast Utah. This warming
trend continues into Friday with low 90s possible for many lower
central and southern valleys as H7 temps climb into the 12C to
14C range. No precipitation or storm activity is expected Friday
given the more stable conditions and eroded moisture, so get out
and enjoy the summer- like temperatures.

.LONG TERM...(Friday night through Wednesday)
Issued at 325 AM MDT Thu May 24 2018

Not much change from 24 hours ago as hot and dry conditions will
be in place for the transition into the weekend. We already have
a Fire Weather Watch out for Saturday which means confidence is
high for the development of hot, dry and windy conditions just
downstream of the system settling into the Great Basin.
Unfortunately, this is not the weather we need right now with new
lightning caused fire starts from Tuesday`s storms. Downstream
blocking over the Caribbean will not only cause the Great Basin
system to stall to our West and keep us dry through the weekend,
but it will aid in keeping heavy rainfall over the Gulf States.
Feast or famine. Both models suggest subtropical moisture being
tapped early Saturday as the Polar and Subtropical jets merge over
the Southwest. Unfortunately, this moisture source looks to be
forced into the Southern Rockies where it will join Gulf of Mexico
moisture, which is then transported northward along the High
Plains for heavy rainfall production east of the divide. So when
will we get rain? This will really depend on which medium range
model verifies the best. GFS still wetter with a broader
circulation while the compact EURO keeps the bulk of the
precipitation outside our CWA. Again, wetter toward Wyoming and
most likely staying dry near the 4 Corners. Going into the middle
of next week, the models are hinting that a more summer-like
pattern is beginning to emerge with the subtropical high moving
over the Lower Rio Grande Valley. This could add a bit more
moisture into the southwest flow and bring us a better coverage of
afternoon storms. Though at this point, this is nothing more than
just a wish-cast.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 325 AM MDT Thu May 24 2018

VFR conditions will prevail under mostly sunny skies for the next
24 hours. Storms are possible this afternoon over the eastern
Uinta mountains in NE Utah but should have minimal impacts on TAF
sites aside from some gusty outflow winds possible at KVEL.


Issued at 325 AM MDT Thu May 24 2018

A dry and warming trend will continue through the weekend
underneath a building ridge of high pressure to the south and
east. The next Pacific low pressure system will move into the
Great Basin on Saturday, resulting in increasing southwest flow
as well as the potential for critical fire weather conditions to
develop across much of western Colorado. As a result, a Fire
Weather Watch remains in effect for Saturday over much of western
Colorado, where fuels are deemed critical at this time. This watch
was expanded this morning to include the rest of the western
Colorado zones where fuels are dry.

It should be noted that recent rainfall over the past several
days may have changed some fuels to not critical, especially in
northwestern Colorado. If that is the case, we would encourage
our partners to update the fuels status in their respective zones
as soon as possible.


CO...Fire Weather Watch from Saturday morning through Saturday
     evening for COZ200-202-207-290>295.



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