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000
FXUS65 KGJT 261934
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
134 PM MDT Fri Apr 26 2024

.KEY MESSAGES...

- Widespread showers and thunderstorms expected again this
  afternoon. Moderate rainfall and small hail is possible.

- A potent system will move through the area this evening
  through Sunday morning bringing much cooler temps, valley rain
  and mountain snows to the region.

- Generally 6 to 12 inches of snow is expected above 9000 ft
  across most mountain ranges between today and Sunday morning.


&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 130 PM MDT Fri Apr 26 2024

A modest low pressure system is currently located over the
Nevada/Utah state line placing us in prefrontal southwest flow.
Moisture continues to advect into the region within this flow
allowing PWAT to almost reach 0.50" at GJT this morning. Lapse rates
remain steep thanks to the shortwave that passed through yesterday.
Surface heating has cause convection to develop. There has been
quite a bit of cloud cover this morning due to this moisture. The
main uncertainty is how much instability can build with all of these
clouds. Thus far there are a few thunderstorms so there is at least
100-200 j/kg in spots. Some models predicted upwards of 300 j/kg
this afternoon, which is looking like a slim chance. If that can be
realized then some small hail could occur with the strongest cells.
Pockets of moderate rainfall seem likely given the moisture values.
Scattered to widespread showers and storms will continue this
evening and overnight across most of the forecast area as the low
pressure approaches from the west. Snow levels are around 9-10
kft now, but may drop tonight closer to 8-9 kft so minor impacts
are possible around the mountain passes.

Tomorrow morning the low pressure passes overhead and therefore
large-scale lift is maximized. The low will drag a cold front
through the region during this time as well. One thing the models
have been hinting at for the last few runs is a an area of enhanced
lift wrapping around the low from NE CO to NW CO then back to SE CO
in the afternoon. Expect this will support a cluster of showers and
or stratiform rainfall along with a few thunderstorms so chances
continue. Snow levels hover around 7-8 kft tomorrow and tomorrow
night. The low finally exits the region tomorrow evening so a
majority of the precipitation shuts down. The moisture is not quick
to leave so lingering orographic showers will continue through the
night. The chances for snow to stick to the roads will be highest at
night, which may impact travel in the mountains. Some higher valleys
may receive snow will little to no accumulation. In general 6-12
inches is expected above 9 kft by Sunday morning.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 130 PM MDT Fri Apr 26 2024

In the wake of the large closed low ejecting northeastward into the
central and northern Plains, a weak trailing shortwave embedded
within northwesterly mid-level flow will act on residual moisture
and keep orographically driven showers going across the higher
elevations and adjacent valleys on Sunday. Given a lack of large
scale forcing, showers and resulting QPF are expected to be light
and generally around a tenth of an inch. Drier air advecting in will
keep most of the lower desert valleys dry... allowing for a slight
bump in temperatures. Higher up, lingering cool air will also mean
some additional light accumulations of snow in the mountains,
particularly along the Continental Divide. So with all of that being
said, Sunday`s weather offers some slight improvements in spots, but
otherwise stays fairly unsettled overall.

Looking ahead to next week, the mean 500mb height pattern features a
sprawling ridge across the northeast Pacific Ocean and troughiness
over the northwest CONUS. That synoptic configuration generally will
keep our CWA underneath west to northwesterly flow. Numerous waves
are progged to clip the northern half of the forecast area through
the remainder of the long term period, with potentially a stronger
storm developing Wednesday into Thursday. This suggests that our
unsettled pattern will more or less continue through the week with
near daily chances of showers and possibly a few storms. This is
especially the case across northeast Utah, northwest Colorado, and
the Continental Divide mountains which will likely be closer to the
storm track. Given the increased chances for clouds and showers
there, temperatures should remain on the cooler side. Outside of
those aformentioned areas though, like the lower desert valleys of
eastern Utah and western Colorado, a mainly dry and increasingly
warmer pattern is looking likely with temperatures climbing back
into the 70s and even 80s. Safe to say, if you aren`t happy with the
upcoming weather pattern, chances are you won`t have to go very far
to experience something different.&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1143 AM MDT Fri Apr 26 2024

Scattered showers and storms will roam across much of eastern
Utah and western Colorado this afternoon and evening. While VFR
should mostly prevail, brief periods of MVFR are probable near
any showers and storms. Any stronger shower or storm can produce
erratic and gusty winds. Scattered instances of ILS breakpoint
ceilings are likely too, becoming more widespread later this
evening and overnight. Isolated to showers likely linger through
the night and into the morning hours on Saturday, with rain
changing to snow for some of the high elevation terminals like
KTEX and KASE. Longer periods of MVFR with brief periods of IFR
are likely, especially in the mountains.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory from 6 PM this evening to 6 AM MDT
     Sunday for COZ004-009-010-012-013-018-019.
UT...Winter Weather Advisory until 6 AM MDT Sunday for UTZ023.

&&

$$

SHORT TERM...KJS
LONG TERM...MDM
AVIATION...TGJT