405
FXUS65 KGJT 160621
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1221 AM MDT Wed Jul 16 2025

.KEY MESSAGES...

- Above-normal temperatures remain status quo through the seven-
  day forecast though a slight downward trend is expected after
  midweek.

- Gusty outflow winds, lightning, and storms with little
  rainfall remain threats through midweek.

- The trend for increased moisture by the end of the week
  continues to boost confidence that storms will transition from
  dry to wet. Storm coverage should increase as a result of the
  moisture as well from late week into the weekend.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 242 PM MDT Tue Jul 15 2025

Isolated showers and thunderstorms are ongoing across the
region. Traffic cameras show that some precipitation is
actually making it to the ground, but considering how dry our
lower atmosphere is, virga is still anticipated with many of the
showers and storms. As a result, the main concerns with
thunderstorms are gusty outflow winds and lightning. Small hail
is also possible, particularly with the stronger storms near our
southern mountains. CAMs show most storm activity ending after
sunset, but lingering showers may persist into the overnight
hours. Tomorrow moisture advection will increase shower and
storm coverage across the region, and increase chances of
precipitation making it to the ground.

With moisture moving in dryness should subside a bit over the
coming days, but today and tomorrow afternoon relative humidity
values will still drop below 15% in many areas, particularly in
desert valleys. As a result, localized Red Flag conditions are
possible through the short term where gusts exceed critical fire
weather thresholds. High temperatures will remain above
average, but tomorrows highs are expected to be a few degrees
cooler than today.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 242 PM MDT Tue Jul 15 2025

On Thursday, the high pressure begins to migrate towards the
Southern Plains allowing for southerly flow over us. This should
advect better moisture into the area so expect another round of
afternoon convection with the highest chances across the south. On
Friday and Saturday a weak low pressure moving northward over the
Baja may help to enhance the southerly flow and moisture advection.
Therefore the coverage of showers and storms looks to increase
across the area. The potential for moderate to heavy rainfall looks
to increase during this period as well as PWAT values approach 0.75-
1.0 in, 700 mb mixing ratios around 7 k/kg and dew points above 40
F. One factor working against heavy rain for the lower valleys is
the warm conditions supporting sub-cloud evaporation. Although it is
not out of the question given the moisture. The higher terrain may
end up being primed for heavy rain, rock slides and debris flows.
Eventually perhaps late in the weekend the northern jet stream sinks
southward causing drier air to filter in from the west. This could
change the afternoon convection coverage and intensity. With
increasing moisture and cloud cover, high temperatures begin a
steady decline towards more seasonable temperatures by the time the
weekend arrives. However, this will also prevent overnight lows from
cooling off as much. Lows are projected to be 5-10 degrees above
normal through much of the extended forecast.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1126 PM MDT Tue Jul 15 2025

Isolated to scattered showers continue across eastern Utah and
Western Colorado near the Utah border. With the dry surface
layer, little rain is reaching the ground, but these showers are
producing erratic gusts 20-40 kts. Look for these showers to
diminish overnight and into the morning before showers and
thunderstorms increase again across the region around 18Z that
will last past 06Z Thursday. Primary threats are lightning and
strong outflow winds gusting 45 kts. Otherwise expect VFR
conditions though smoke from local wildfires will have minor
impacts on visibilities at most TAF sites. Expect light winds
through the TAF period with generally westerly winds through
the afternoon.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...GF
LONG TERM...KJS
AVIATION...DB