Area Forecast Discussion Issued by NWS Grand Junction, CO
000
FXUS65 KGJT 181033
AFDGJT
Area Forecast Discussion
National Weather Service Grand Junction CO
433 AM MDT Mon Mar 18 2024
.KEY MESSAGES...
- Showers are possible around the central and southern mountains
today and tomorrow mainly in the afternoon.
- A warming trend begins this week with high temperatures above
normal across the region.
- Enjoy the warm dry weather while it lasts as another storm
system looks to bring more precipitation and a bit of a cool
down late next weekend.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 116 AM MDT Mon Mar 18 2024
A ridge of high pressure orientated east to west is dropping
southward over the Great Basin. This along with a deep trough to our
east is pushing the closed low pressure into southern Arizona. We
will still be left with plenty of moisture today that results in
some instability this afternoon. The ridge and trough have weakened
the lapse rates north of I-70, but across the south the rates are
just steep enough. Without the lack of forcing orographics will be
the main driver for convection late today. Coverage looks to be
isolated at best, but perhaps closer to scattered in the San
Juans. Precip amounts are expect to be minor, so no issues with
that. Elsewhere will enjoy and partly to mostly sunny day. Highs
will be similar to yesterday only slightly warmer for places
that had clouds and showers. Any showers are expected to diminish
in the evening.
Tomorrow a strong subtropical jet works northward and begins to
shear the low pressure apart. Also, it will force it`s eastward
progression over New Mexico. That slight movement in the low
will allow the lapse rates to steepen across the southern half
of the forecast area. With moisture in place that causes yet
another afternoon with instability, a little more than today.
Therefore expect scattered showers later in the day mainly in
the southern and central mountains. North of I-70 appears it
will still be under influence of the ridge and so no cape. The
central and southern mountains will be favored for a couple
inches of snow with limited impacts. High temperatures will end
up a few degrees warmer across the area.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 116 AM MDT Mon Mar 18 2024
Lingering showers across portions of southeast Utah, southwest
Colorado, and the central and southern Continental Divide mountains
Tuesday night will gradually diminish by daybreak Wednesday morning.
The last of our stubborn closed low, which by Wednesday will have
devolved into an open wave, will slowly push off to the east by the
end of the day. With lingering moisture across the south combined
with diurnal heating, would not be surprised to see a few more
isolated to widely scattered pop-up showers across the central and
southern Continental Divide mountains Wednesday afternoon and
evening. Given limited forcing and only modest moisture, any
QPF/snowfall will be very light with negligible impacts, if any. By
Thursday, ensembles agree that broad and fairly low amplitude
ridging with quasi-zonal flow aloft builds in across the Great Basin
and Four Corners states. This synoptic pattern largely remains
unchanged through Friday and Saturday. While that setup will likely
result in mainly dry and increasingly warm weather through the late
week and early weekend period, a series of weak waves moving through
the nearly zonal flow aloft will be enough to produce some scattered
afternoon showers, mainly across the higher elevations and
especially along the Continental Divide. Given warm temperatures,
any impacts from high elevation snowfall will again be limited.
Speaking of warm temperatures, the late week and early weekend
period will be feeling quite springlike, which is very fitting
considering March 19th marks the first day of spring. Highs across
the lower elevations of eastern Utah and western Colorado will be
running 5 to 10 degrees above normal, which equates to highs well
into the 60s to near 70.
By Sunday, the weather pattern turns much more active, unsettled,
and a bit cooler as a large trough is progged by ensembles to dig
across the western CONUS. As of right now, there is reasonable
agreement with this pattern between the various modeling centers.
Widespread precipitation is looking like a decent bet with rain
favored in the valleys and snow in the mountains. Just how impactful
and concerning this storm will be is still to be determined, but
southwest flow ahead of its arrival combined with the fact that the
calendar is reading deeper into March now means a milder storm is
more likely. That should generally keep impacts above 7000 or 8000
feet, but we`ll see how things progress as the week goes on.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 433 AM MDT Mon Mar 18 2024
Residual moisture and daytime heating will kick off another round
of orographically-driven showers after 18Z with little impacts
expected. Apart from some occasional breezes, winds will remain
light and terrain-driven with VFR conditions expected through
the period.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...KJS
LONG TERM...MDM
AVIATION...TGJT