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364
FXUS65 KGJT 122201
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
401 PM MDT Wed Jun 12 2024

.KEY MESSAGES...

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- Hot and dry conditions continue Thursday with temperatures 10
  to 15 degrees above climatological averages and near record
  levels for some areas.

- A storm approaches the region Thursday night leading to
  widespread showers and a few thunderstorms favoring the San
  Juan and central Colorado mountains Thursday
  afternoon/evening.

- Expect a short-lived break in the heat Friday.
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&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
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Issued at 401 PM MDT Wed Jun 12 2024

Localized showers/virga and thunderstorms north of the I-70
corridor should diminish by, or shortly after sunset.
Thereafter, expect clearing and cooling during the remainder of
the night. Another hot day on tap Thursday as the upper level
ridge axis shifts overhead. A low moves over the Desert
Southwest during the day which will deliver a weak push of mid-
level moisture. This may bring a few showers/thunderstorms to
the Divide mountains, but most of the area, just much warmer
than normal temperatures with moderate afternoon breeziness.
Lift and moisture increases Thursday night as the low tracks
eastward across northern Arizona. Models were consistent in
suggesting that this will bring a chance of light showers and/or
thunderstorms for the Four Corners area later Thursday night.
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&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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Issued at 322 PM MDT Wed Jun 12 2024

Friday looks to be the coolest and most unsettled day of the period
as what was a closed low off the SoCal coast tracks inland and moves
across the Great Basin as an open wave by Friday morning. This open
wave trough will move across the CWA Friday afternoon and exit
Friday evening. This low will pull in some deeper moisture from the
southerly flow ahead of the system, with mixing ratios rising to
around 5 to 6 g/kg and PWAT rising upwards of 0.75 to 0.9 inches by
Friday afternoon. This moisture advection will be starting in the
predawn hours, likely resulting in plenty of cloud cover and some
light showers across the area by Friday morning. The timing of this
moisture advection is key to whether we would see stronger
convection and based on the earlier onset, would expect thunderstorm
activity to be more isolated with embedded storms in the afternoon
but generally light rainfall in the valleys with more moderate
precipitation possible in the higher elevations. This is reflected
pretty well in the QPF forecast as well as chance of wetting rain
being higher in the mountains and low in the valleys where gusty
outflow winds are still a concern.  All this cloud cover and more
widespread shower activity means high temperatures on Friday will
take quite a hit as daytime heating will be limited, with high
temperatures on Friday about 12 degrees cooler than the previous hot
day on Thursday. We will end up closer to normal and maybe slightly
cooler than normal for central and southern areas that look likely
to see better shower activity on Friday, which will actually be a
welcome reprieve from the unrelenting early Summer heat.

The trough exits stage right Friday night and is quickly replaced by
drier southwest flow as a high pressure sits over the Desert
Southwest and keeps the PacNW trough at bay, leaving us in a dry
southwest flow this coming weekend into early next week. Some
moisture could linger over the Continental Divide in the far eastern
peaks of our CWA for isolated afternoon convection, but overall,
temperature should warm back up to 5 to 10 degrees above normal. The
increasing southwest flow will result in breezy afternoon winds and
lower relative humidity, especially Sunday and Monday as the jet
associated with the PacNW trough dips into our CWA and tightens the
gradient more. Some of our fuels are drying out and so those areas
with dry fuels will need to be monitored closer as critical fire
weather conditions may result in needing some Fire Weather products.
No precipitation is expected beyond Friday`s unsettled weather as
any shower activity with the PacNW trough later in the weekend into
early next week looks to remain north of the Colorado-Wyoming
border. So, conditions look to return to hot and dry shortly after
our brief cool, cloudy and wet spell on Friday.
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&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1201 PM MDT Wed Jun 12 2024

VFR conditions will be the rule across eastern Utah and western
Colorado during the next 24 hours. Isolated, high-based
thunderstorms are possible over the higher terrain, and gusty
outflow winds could potentially impact KVEL, KHDN, KEGE and KASE
from 20Z through 02Z/Thu. Otherwise, moderately breezy west
winds are expected at TAF sites this afternoon which will
diminish by sunset before shifting to a light drainage flow
later in the evening. Expect few clouds overnight.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...None.
UT...None.

&&

$$

SHORT TERM...NL
LONG TERM...MDA
AVIATION...NL