392
FXUS65 KGJT 161749
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1149 AM MDT Wed Jul 16 2025

.KEY MESSAGES...

- Gusty outflow winds, lightning, and storms with little
  rainfall remain threats, especially along and north of the
  I-70 corridor.

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

- The weather dries out Sunday into early next week bringing a
  return of near critical fire weather conditions.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 433 AM MDT Wed Jul 16 2025

Satellite imagery shows the high pressure to the southeast pulling
mostly mid-level moisture north out of Mexico through Arizona into
eastern Utah and Western Colorado. This moisture supported by an
upper-level trough is producing high based showers overnight
producing some gusty outflow winds. These showers are diminishing
going into the morning hours, but with diurnal heating, will pick up
again by noon. Look for coverage to increase over yesterday still
favoring the higher terrain and especially the southern mountains
with more rain reaching the ground later in the day as the lower
levels pick up moisture from the virga. Temperatures today will run
a few degrees above average, a few degrees cooler than yesterday due
to the increased clouds and showers. Showers and thunderstorms will
diminish through the evening with a few possibly lingering through
the overnight mostly in the Four Corners area and the San Juans.

Increasing moisture Thursday will promote more coverage of showers
and thunderstorms generally along and south of the I-70 corridor
with some areas in the San Juan Mountains receiving heavier rain
that could lead to some localized flooding in some areas. Stay
tuned on this. Temperatures will be yet a few degrees cooler than
today, more near normal for mid July. With the lower atmosphere
getting more saturated, the strong outflow winds will be less of a
threat, but we can still expect to see gusts to 40 mph. Dry
lightning will still be a threat, especially across the northern
2/3rds of the CWA.

&&

.LONG TERM /THURSDAY NIGHT 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 /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1142 AM MDT Wed Jul 16 2025

VFR conditions are generally expected to continue through the
TAF period. Visibility may lower at some sites due to wildfire
smoke. Isolated to scattered showers and thunderstorms are
expected to begin shortly and last through sunset. Some storms
may linger overnight, mostly near the San Juans and in the Four
Corners region. The primary concerns with thunderstorms will be
gusty outflow winds and lightning. Winds should become light
overnight.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...DB
LONG TERM...KJS
AVIATION...TGJT