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436
FXUS65 KGJT 151016
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
416 AM MDT Sat Jun 15 2024

.KEY MESSAGES...

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- A few very isolated showers, maybe a quick storm, possible
  this afternoon for the northern half of the CWA.

- Hot and dry weather continues as southwesterly winds pick up
  resulting in critical fire weather conditions on Sunday and
  Monday.

- The Fire Weather Watch in effect for southeast Utah and
  portions of southwest and west-central Colorado has been
  upgraded to a Red Flag Warning. Another Red Flag Warning has
  been issued for Monday for the same areas.
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&&

.SHORT TERM /THROUGH SUNDAY/...
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Issued at 234 AM MDT Sat Jun 15 2024

Low amplitude ridging builds in today while a closed low moves
into the Pacific Northwest. Out ahead of this low, a shortwave
will move across the Intermountain West. NBM guidance was
showing no PoPs for our area today but with residual moisture
still lingering from yesterday, and that weak little wave
moving through, wouldn`t be surprised to see some convection
fire. The NAMNEST and other short range models agree so blended
these solutions into the current forecast and introduced some
very isolated convection to the higher terrain of UT and CO,
mainly for the northern half of the CWA. Some deeper mixing will
also bring some gusty winds to the surface this afternoon,
again mainly for the northern half of the CWA. Outside of all
that, we`ll see high temps jump 7 to 10 degrees from what we saw
yesterday with increased cloud cover over the higher terrain.

Sunday, flow becomes quasi-zonal as the low pressure center
moves along the US/Canadian border. The upper level support
(100 kt jet streak) for this system will be moving towards our
area and with another day of deeper mixing expected, widespread
gusts of 20 to 35 mph will be common. The surface pressure
gradient will also tighten further bringing increasing chances
for gusty winds. Drier air will continue to advect into the CWA
and these conditions will bring critical fire weather conditions
to those zones with critical fuels. Went ahead and upgraded the
Fire Weather Watch for Sunday to a Red Flag Warning as
confidence remains high with the gusty winds and low humidities.
Even stronger winds are expected Monday so issued a Red Flag
Warning for that day as well. With zonal flow and generally
neutral advection, high temps will be similar to those seen
today. Look for plenty of sunshine to end out the weekend.
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&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
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Issued at 234 AM MDT Sat Jun 15 2024

As we approach the summer solstice, it seems fitting to discuss
a persistent warm and dry pattern developing here on the West
Slope this week. Having already tied or broken numerous
temperature records this past week, some of you might be
suffering some early summer fatigue. For you sun seekers, Summer
2024 has reported for duty. A deep Canadian trough digs into
the Great Basin early Monday morning with a respectable jet max
lined up along its cold front and brisk southwesterly flow out
in front. This general pattern is expected to hang around into
midweek, as the broad cyclonic circulation over Canada keeps us
under the southwesterly feed along its southern edge. A brief
dry cold front on Tuesday will dip area temperatures
momentarily, but then we quickly rebound back into the hot and
dry regime. A couple of details of note will be the critical
fire weather conditions that are expected on Monday, followed by
the cold front passage Monday evening. Winds, Monday afternoon,
are expected to gust around 30-40 mph around the area. Single
digit relative humidities in our desert/low elevation valleys
will continue Red Flag conditions for the CWA. Temperatures will
top out in the 90`s Monday afternoon and a few locales might
get some relief from scattered cloud cover ahead of the front
later Monday afternoon. Extremely dry boundary layer conditions
will keep the precipitation forecast at zero though. Temperature
relief on Tuesday following the front will give us a brief
break, then Wednesday we surge back up. A series of weak waves
coming ashore in the PACNW attempt to deliver some moisture
Thursday and Friday, along with weak shortwave forcing. With the
dry conditions in place, it will take work to get the lower
levels saturated. This will probably be a gusty virga shower
event, but still too early to get wrapped up in details.
Afternoons will remain breezy and hot to close out the work week
with our deserts in triple digit territory and our mountain
towns in the 80`s. Summertime rolls on.
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&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1150 PM MDT Fri Jun 14 2024

VFR conditions have taken the controls and will hang on through
the TAF period for most terminals around the region. Westerly
winds will pick Saturday afternoon and gust to around 30 mph
across the region with a few stronger gusts on the higher
terrain. Scattered showers and perhaps an isolated thunderstorm
will form on terrain favoring the northern Continental Divide
and its western shoulders on Saturday afternoon. This will bring
the usual threats for strong outflow winds, 40-50 mph in most
cases. Winds will subside towards sunset and VFR conditions
return by the tail end of this TAF period.

&&

.FIRE WEATHER...
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Issued at 234 AM MDT Sat Jun 15 2024

Strong southwest winds and low relative humidity Sunday and
Monday remain in the forecast and will generate critical fire
weather conditions for both days. Model consistency has been
steadfast in these stronger winds and dry conditions materializing
so confidence continues to grow with the forecast. The latest
HDWI still peaks just below the 90th percentile for this time of
year so decided to upgrade the Fire Weather Watch to a Red Flag
Warning for Sunday for southeast Utah and portions of southwest
Colorado and west- central Colorado from late Sunday morning
through Sunday evening. Winds are forecast to be stronger on
Monday so another day of critical fire weather conditions is
expected. With that in mind, went ahead and issued another Red
Flag Warning for the same areas and times for Monday.
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&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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CO...Red Flag Warning from 11 AM to 10 PM MDT Sunday for COZ203-207-
     290>293.

     Red Flag Warning from 11 AM to 10 PM MDT Monday for COZ203-207-
     290>293.

UT...Red Flag Warning from 11 AM to 10 PM MDT Sunday for UTZ490-491.

     Red Flag Warning from 11 AM to 10 PM MDT Monday for UTZ490-491.
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&&

$$

SHORT TERM...TGR
LONG TERM...LTB
AVIATION...TGJT
FIRE WEATHER...TGJT