224
FXUS65 KGJT 231127
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
527 AM MDT Mon Sep 23 2024

.KEY MESSAGES...

- A weak disturbance in northwest flow combined with modest
  levels of moisture lingering from this weekend`s storm is
  expected to generated isolated storms over the higher terrain
  this afternoon with the southern San Juan Mountains favored.

- Dry and warm conditions are expected during the remainder of
  the week as high pressure settles over the region. Near record
  highs are expected from Thursday through the weekend.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 328 AM MDT Mon Sep 23 2024

Aside from far southwest Colorado, skies were clear over much
of the region early this morning. Clouds hanging on over the
south appeared to be due to the trailing, positive tilt mid-
level trough stretching west-southwestward from the central
Plains according to latest RAP13 analysis. Daytime warming will
generate scattered cumulus over the higher terrain beginning
late this morning. During the afternoon a low amplitude mid-
level short wave trough will sweep southeastward over the area
which should generate some isolated showers/thunderstorms over
the higher terrain despite limited moisture. NAM and GFS both
suggested moisture over the southern San Juan Mountains a bit
deeper as in previous runs, so kept better chances north and
east of Pagosa Springs. Meanwhile, increased sunshine and warm
air advection should cause temperatures to recover to near
normal or just a bit above this afternoon.

Expect skies to clear this evening as a ridge of high pressure
builds over Great Basin and Intermountain north. This will
allow for strong radiational cooling and morning lows close to
normal. The ridge is driven eastward on Tuesday as a long wave
trough moves toward the West Coast. A subsidence inversion
becomes apparent in forecast soundings near 600 mb as the high
takes hold. Consequently, look for dry and warm conditions with
plenty of sunshine on Tuesday. Afternoon highs warm by a degree
or two putting readings right around 5 degrees above seasonal
norms.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 328 AM MDT Mon Sep 23 2024

A classic omega block, albeit short lived, will be centered over
the CWA at the start of the long term period. High pressure
directly overhead will bring sunny skies, light winds, and
once the center of high pressure starts shifting eastward,
warming temperatures. An approaching trough coming ashore across
the PacNW on Wednesday will be the push needed to force the
ridge axis and high pressure center further east. This will
cause winds to become southwesterly allowing warm air advection
to kick in. High temperatures here on out will run about 10, to
maybe near 15, degrees above seasonal values. In fact, forecast
highs from Thursday through Sunday will be near record levels.
Dry and clear skies will continue to be the rule as disturbances
are expected to ride up and over the ridge keeping any inclement
weather well to our north. The remainder of the long term, as
per deterministic models, will rebuild high pressure over the
desert southwest as much more active weather materializes along
the Gulf Coast and central states. We`ll keep those dry and warm
conditions in place with generally light winds also remaining
in place.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 527 AM MDT Mon Sep 23 2024

Isolated showers are expected to develop this afternoon over the
mountains, though this activity isn`t likely to impact TAF
sites directly. Outflow winds are possible for KTEX and KDRO and
negligible for the remaining TAF sites. Otherwise, expect VFR
conditions with few clouds. Winds will be light and terrain
driven during the period,

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...NL
LONG TERM...TGR
AVIATION...NL