Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 270951

Area Forecast Discussion
National Weather Service Grand Junction CO
351 AM MDT Tue Jul 27 2021

.SHORT TERM...(Today through Wednesday)
Issued at 351 AM MDT Tue Jul 27 2021

High pressure building into the High Plains today looks to bring
some capping to the thunderstorm activity over the northeast CWA.
Farther to the West very little change can be expected with
mositure still in place across the 4 Corners and up along the
Colorado/Utah border. HiRes model trends show the storms firing
over the southern mountains then taking on an east to northeast
drift through the afternoon and evening. Models are also hinting
at a weakness rotating clockwise across the CO/NM border into SE
Utah and could be focus for more organized storms. This has been
the persistent pattern the past few days with low level moisture
pooled in the western valleys leading to robust CAPE values for
storms to feed into as they come off the terrain. Would suspect
localized flooding will once again be a concern especially with
pockets of saturated soils over SW.Colorado into SE.Utah. The
Paradox/Disappointment Valleys into Castle Valley and the National
Parks seem to be the areas of interest today. If the storms to
get more organized it`s also likely another mesoscale feature or
two will come together and keep things going well into the
evening. There also seems to be a feature feeding a flux of low
level moisture into southeast Utah by late evening that also keeps
some storms firing past sunset and did try and trend an early
guess at PoPs this way. The center of the high will drift farther
East into the Central Plains and this looks to pull moisture back
into our northeast CWA. We can expect more afternoon storms to
form on the terrain and drift northward into the valleys through
the afternoon and likely congeal once again into one or more
organized clusters due to boundary interactions. Temperatures
hover above normal most areas except the early cloud cover starts
in the plume of moisture. Much like on Monday where Craig was
warmer than Moab.

.LONG TERM...(Wednesday night through Monday)
Issued at 351 AM MDT Tue Jul 27 2021

Similar conditions are expected through the end of the week as
the high wobbles slightly to the east. PWATs look to increase even
more during this time as a remnant tropical low pressure from
Mexico looks to be advected in the flow. Regardless, the
atmosphere will remain primed for heavy rain and anyone planning
to travel should stay up-to-date on the latest forecast and road
conditions before heading out.

The high will begin to track southwest as a Pacific midlevel trough
lifts across the northwestern CONUS during the weekend. The base of
this shortwave will brush our CWA early next week, providing
additional lift for showers and storms. Beyond that, drier air looks
to push into the region. Until that time, cool and unsettled
conditions will prevail.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1218 AM MDT Tue Jul 27 2021

A thunderstorm in vicinity of KCNY will last though 08Z leaving
dissipating showers and high cloudiness to drift over the
remainder of the CWA. VFR conditions will prevail over the next
24 hours with another round of thunderstorms impacting the 4
Corners up to I-70 corridor tomorrow afternoon and evening.


Issued at 351 AM MDT Tue Jul 27 2021

Localized areas of heavy rainfall are possible again across the 4
Corners into the central border area of Utah and Colorado. Several
days of heavy rainfall producing thunderstorms have impacted this
same region as well. Due to the uncertainty of coverage of storms
today have not issued a watch but will continue to interrogate
real-time and short term model trends. The area of highest concern
would be from the Paradox Valley over the Red Rock Country
including the Utah National Parks.




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