919
FXUS65 KGJT 201116
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
516 AM MDT Wed Aug 20 2025

.KEY MESSAGES...

- Hot and dry conditions remain through the end of the week,
  with near-record high temperatures expected.

- A few isolated showers or thunderstorms will be possible over
  the San Juans in the afternoon.

- Confidence is high that moisture will return starting
  tomorrow, increasing chances of precipitation and bringing
  some cooler temperatures for the weekend.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 304 AM MDT Wed Aug 20 2025

High pressure remains overhead today, helping to keep skies mostly
clear and temperatures hot. Highs this afternoon will run 10-15
degrees above normal, approaching record values yet again. Some very
modest moisture continues to nudge northward, filling in mainly
across the San Juans. This will fuel afternoon cloudiness and
isolated to widely scattered showers or thunderstorms over the
higher terrain of the southern and central Divide. The main concerns
remain gusty outflow winds and lightning, however, with very low
(<20%) chances of wetting rain today.

The high is expected to wobble a bit tomorrow in response to a wave
passing to our north, shifting the moisture plume to the east. We`ll
see PWAT values climb through the day tomorrow, approaching near-
normal values for late August. Current guidance has PWATs climbing
100-120% of normal across the region tomorrow, which amounts to 0.75-
1.00 inches. This is a substantial improvement over the 0.20-0.30
inch PWAT values we`ve seen the last few days. As a result, we will
see an increase in shower and storm coverage tomorrow afternoon,
although it will still be confined to the higher terrain of the
southern and central Divide mountains. Chances of wetting rain
remain low (<20%) tomorrow, as surface levels will still be quite
dry. Instead, gusty winds and lightning, along with perhaps some
small hail, will be the main concerns. Temperatures will stay 10-15
degrees above normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 304 AM MDT Wed Aug 20 2025

The high pressure will be directly overhead at the start of the long
term period. Ensembles continue to indicate moisture increasing
thanks to flow around the high pressure. The deterministic EC and
GFS both show PWATs increasing from north to south to about 150% of
normal by Saturday, and by Sunday a second push of moisture
increases this to 200%. This increased moisture looks to stay
through the start of the work week. Shortwaves will rotate around
the high pressure and work on this moisture, allowing more
widespread showers and thunderstorms to fire. Coverage will slowly
increase day by day, with the best coverage looking to be Sunday
onwards. Cloud coverage will have a significant impact on whether
strong convection forms in the afternoon or a more stratiform event
occurs. If daytime heating is at a maximum, some storms will likely
bring heavy showers to the region while continued cloudiness will
bring a more soaking type of rain. These will probably be game day
decisions to make on how each day will play out. Having said all
that, the last several model runs have all shown this increase in
moisture, showers, and storms so confidence is increasing that this
monsoon push will come to fruition.

Hot temperatures on Friday will start decreasing heading into the
weekend, dropping to near normal values by Sunday, and possibly
below normal by Monday due to clouds and precip.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 514 AM MDT Wed Aug 20 2025

Skies will remain mostly clear through the next 24 hours,
although some passing mid and high-level clouds will be
possible. Some clouds and showers or thunderstorms will be
possible over the San Juans this afternoon, with main concerns
being gusty and erratic winds for terminals such as KTEX and
KDRO. A fire north of KEGE could produce enough smoke to reduce
visibility at that terminal. Winds will be generally light and
follow typical terrain driven patterns. VFR conditions will
prevail, although smoke or brief heavy rain could lead to short
periods of MVFR conditions.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...BGB
LONG TERM...TGJT
AVIATION...TGJT