699
FXUS65 KGJT 010934
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
334 AM MDT Mon Sep 1 2025

.KEY MESSAGES...

- Showers and thunderstorms continue on the San Juans today and
  tomorrow then begin expanding up the Divide Tuesday.

- Temperatures trend nearly 5 degrees above average through mid
  week then cool with a potentially more active storm cycle.

- More widespread precipitation is possible on Friday and into
  the weekend, given the potential for rich extra-tropical
  moisture.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 315 AM MDT Mon Sep 1 2025

Weak forcing down in the southeast corner of the CWA has kept
some mid level cloud cover around Pagosa Springs this morning. A
weak shortwave is producing some light convection with a few
lightning strikes on the New Mexico side of the line. High
pressure will continue to amplify over the Great Basin today.
This will send temperatures 3 to 5 degrees above average this
afternoon. Isolated showers and thunderstorms will form on the
San Juans and along the edge of the Divide north of there today.
Gusty outflow winds will remain the biggest threat aside from
lightning this afternoon. Storms will be short-lived and things
quiet down around sunset. Overnight lows Tuesday morning will
trend a few degrees warmer too beneath the subsident air mass.

With the ridge arced over the Great Basin Tuesday, the door
opens a smidge for some additional monsoonal moisture to trickle
into the region. Nothing exceptional here, but break-even
amounts for early September. This will keep the daily activity
on the San Juans refreshed and likely send a few showers up the
Divide near Vail Pass. These will be pretty low POPs(like 10
percent), but worth mentioning given the trend we see towards
more moisture by late week. Afternoon highs will feel hot again
Tuesday, pushing into the 90s for our low valleys in eastern
Utah and western Colorado. This warmup looks like it could get
put to bed by late week though, but I`ll leave that to the
discussion below.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 1226 PM MDT Sun Aug 31 2025

An area of high pressure will be centered over the Four Corners
Tuesday, with a ridge extending northward through the Intermountain
West. A strong area of low pressure will be spinning off the Pacific
Northwest coast, with a trough extending down the West Coast. This
trough is expected to push east through the remainder of the week,
eventually breaking the high down just a bit and shunting it
slightly east. This will allow for a moisture return starting Friday
and lasting through the weekend. Ahead of this though, we remain
warm and dry. PWAT values are forecast to be near to below normal
through Thursday, with the best pockets of moisture over the higher
terrain of the San Juans and Colorado Divide, where a few isolated
showers or thunderstorms will be possible. The main threats with any
convection that does develop will be gusty winds, lightning, small
hail, and brief heavy rain. Elsewhere, expect abundant sunshine and
temperatures near to around 5 degrees above normal through the end
of the week. As moisture begins to return for the weekend, which
both deterministic and ensemble guidance are indicating, shower and
thunderstorm activity will start to expand out from the higher
terrain, and chances for heavy rain will increase. Temperatures are
also expected to begin dropping in response to the increased clouds
and showers. In the meantime, enjoy the abundant late summer
sunshine and warmer temperatures.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1137 PM MDT Sun Aug 31 2025

Mostly VFR conditions will prevail again tonight and tomorrow. A
few clouds linger along the Divide of southern Colorado, but
these will thin gradually overnight. More sunshine and light,
ambivalent winds are in store for Monday. A few showers will
form on the San Juans again, but quickly taper by late afternoon
and return us back to quiet VFR conditions overnight again.
Showers will produce a few MVFR ceilings, gusty outflows, and
brief downpours before decaying.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

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