Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
000
FXUS65 KGJT 120541
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1141 PM MDT Mon Mar 11 2024

.KEY MESSAGES...

- Isolated to scattered showers are possible tonight. Minor
  accumulation of snow possible in the mountains.

- A strong cold front brings the best chance for widespread
  precipitation Wednesday and Thursday.

- In general 6 to 12 inches of total snow is possible for most
  mountain ranges Tuesday evening through Thursday morning.

- There is some uncertainty with the forecast for Thursday and
  Friday, but there is potential for another round of snow for
  the southern mountains.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 143 PM MDT Mon Mar 11 2024

West to southwest midlevel flow is in place today, which has
resulted in warm temperatures. Not quite record highs, but well
above normal. A weak trough will track over the CWA this evening and
overnight. It may generate some showers, but accumulations appear to
be minor due to a lot of dry air and weak forcing. Perhaps a dusting
to a few inches in the higher elevations by sunrise. Tomorrow the
showers clear out allowing mostly dry conditions across the area.
Highs will again be above normal, but increasing clouds will keep it
a few degrees cooler than today. By tomorrow evening the next system
quickly approaches from the northwest. This main trough is comprised
of several shortwaves, the first of which passes overhead tomorrow
night. Expect widespread showers with this round as moisture and
lift increases. A cold front will accompany the system allowing for
snow levels to drop especially across the northern valleys. Heavy
mountain snow will be possible Wednesday morning so the commute over
some of the passes might not be smooth. It is uncertain where the
snow levels will end up by morning. Also, the warm pavement
temperatures may be able to melt light snow. This makes it difficult
to determine the impacts. Given all of the variables the impacts
should stay relatively low.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 143 PM MDT Mon Mar 11 2024

Widespread showers continue across most of eastern Utah and western
Colorado through at least Wednesday morning as a strong cold front
and trough push through the region. Precipitation type will mostly
be in the form of snow up high with snow levels hovering around 5000
to 6000 feet. That means primarily rain will fall in the lower
desert valleys before transitioning to a rain/snow mix and then all
snow as you go up in elevation. Forcing from the front and within
the exit region of a cyclonically curved jet aloft could promote
heavy snowfall rates above 1 inch per hour at times in the mountains
for a brief time Wednesday morning before rates relax into the
afternoon, evening, and overnight hours as forcing and coverage
wanes. Snowfall will favor the western Colorado and southeast Utah
mountains where a widespread 6 to 12 inches is forecast through
Wednesday night with locally higher amounts possible. Winter Weather
Advisories go through 06Z Wednesday night for all mountain ranges
except the central mountains which go through 12Z Thursday morning.
Snow from this messy system doesn`t really completely "end"
Wednesday night into Thursday morning but there will be enough
breaks and lulls across most of the CWA to cut off the highlights at
those aformentioned times. Given the heaviest snow will fall from
Tuesday night through Wednesday morning, travel through the high
country and especially over high mountain passes could become
difficult. Give yourself plenty of extra time to safely reach your
destination.

After the first wave exits, attention then turns to a very strong
closed low that will be deepening as it descends southward from the
Pacific Northwest into Arizona Wednesday into Thursday... and
remaining nearly stationary there through at least Friday and
Saturday. Uncertainty still exists regarding the exact track and
evolution of this closed low, but the latest WPC ensemble cluster
analysis favors a more even blend of the EPS/GEFS/CMCE which
suggests a low position in southwestern Arizona. This will focus a
deep tap of moisture into the southern half of the forecast area,
with ensemble mean precipitable water values reaching 150 to 200
percent of normal Thursday night into Friday. Moist ascent across
the San Juans and southeast Utah mountains could lead to very heavy
snowfall rates with the potential for totals well over a foot from
Thursday night through early Saturday morning. In fact, NBM
probabilities of 48-hour snowfall totals over 12 inches already
ranges from 50 to 65 percent for a large portion of the San Juans.
That`s an impressive signal for still being several days away.
Depending on how the closed low evolves beyond that will determine
how much snow lingers into the weekend. We`re still a day or two
away from nailing down the details, but the take home message of
monitoring the forecast and being prepared for a very active period
through at least the end of the week remains. Stay tuned.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1138 PM MDT Mon Mar 11 2024

A few scattered showers are falling overnight thanks to a weak
shortwave disturbance tracking across the mountains. Ceilings
will come down temporarily with these showers, but VFR
conditions are expected to return before daybreak. Winds will
pick up out of the southwest Tuesday afternoon and remain breezy
towards sunset, when they will sit back down. Cloud cover is
expected to begin returning late in this TAF period ahead of the
approaching storm Tuesday evening.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory from 6 PM Tuesday to midnight MDT
     Wednesday night for COZ004-013-017.
     Winter Weather Advisory from 6 PM Tuesday to 6 AM MDT Thursday
     for COZ009-010-012.
     Winter Weather Advisory from midnight Tuesday night to
     midnight MDT Wednesday night for COZ018-019.
UT...Winter Weather Advisory from 6 PM Tuesday to midnight MDT
     Wednesday night for UTZ028.

&&

$$

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.