Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 171750
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
1150 AM MDT Sun Mar 17 2024

.KEY MESSAGES...

- Another round of showers is expected mainly across the
  southern half of eastern Utah and western Colorado today.

- Additional snow accumulations today will generally be minor
  and confined to elevations above 8000 feet.

- A few scattered thunderstorms are possible across southeast
  Utah and southwest Colorado this afternoon. Any stronger storm
  will be capable of producing small hail.

- Unsettled conditions linger through the upcoming week, but
  mainly in the mountains.

- A warming trend begins this week with high temperatures
  pushing into the 60s and 70s across the lower desert valleys
  by Thursday or Friday.

&&

.UPDATE...
Issued at 909 AM MDT Sun Mar 17 2024

The winter storm we`ve had for the last few days is winding down
with just a few showers continuing through he San Juan Mountains
and across the southern areas today. Hence, allowed the Winter
Weather Advisories in the San Juan Mountains to expire. Be aware
that showers will continue across the southern areas of
Colorado and Utah through through this afternoon, some of which
may be heavy at times with a few inches accumulation possible on
the higher elevations. Icy road conditions will also persist on
the high mountain passes. Note that the Colorado Avalanche
Information Center continues to forecast a moderate to
considerable threat for avalanches in the back country across
Colorado with all this new snow.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 245 AM MDT Sun Mar 17 2024

GOES-16 water vapor satellite imagery continues to show a deep,
vertically stacked, closed low pressure system spinning over
western Arizona early this morning. On the far eastern flank of
the mid-level circulation, a plume of deeper moisture can be
seen pushing from northeast Arizona and northwest New Mexico
into southeast Utah and southwest Colorado. This surge of
moisture will be the focus for additional shower and t-storm
activity today, mainly to the south of I-70. Right now, snow is
falling in Durango and along portions of the US-160 corridor
with temperatures near freezing. This activity will slowly
spread northward through the day, but will stall across the
southern half of the CWA as it encounters north/northeast winds
and increasingly drier air to the north. Given a moderating air
mass and no cold advection, precipitation type will be highly
dependent on elevation and diurnal temperature trends. Thus, as
we head into the daylight hours, snow that`s currently falling
in the lower elevations will eventually change to plain rain
with temperatures warming well above 32F. In fact, snow levels
are progged to rise to between 7500 and 8000 feet by the early
afternoon hours, so most appreciable snow will be confined to
elevations above that. Even there, new snow accumulations look
very minor. As a result, no additional winter highlights will be
issued for the last remaining showers of this long and drawn
out storm. The headlines currently in effect will also drop at
15Z unless cancelled sooner.

Aside from the wintry aspect of this storm, we`ll also need to
keep an eye out for some scattered thunderstorms later this
afternoon and evening across southeast Utah and southwest
Colorado. After this morning`s activity moves north, there may
be a break and some partial clearing heading into the afternoon.
The resulting diabatic heating with a strong mid March sun
angle working on a moist air mass would support the development
of steepening lapse rates and roughly 250-500 j/kg of SBCAPE.
Along with the instability, high resolution forecast soundings
depict about 10 to 20 knots of effective bulk shear. This
environment would be favorable for brief updraft/downdraft
enhancement and the potential for small hail or graupel. Brief
heavy rain (or snow if high enough in elevation) would accompany
any stronger cells as well.

Elsewhere, mainly dry and quiet weather is in store for today
with intervals of clouds and sun. High temperatures will top out
near to slightly below normal across the north and solidly
below normal (by as much as 5 to 15 degrees) across the south.

Heading into tonight, showers will likely linger across
portions of southeast Utah and southwest Colorado before
diminishing around or just after daybreak. A push of dry air
from the north will surge southward and encompass the entire
CWA, effectively cutting us off the tap of moisture to the
south. Aside from a stay pop-up shower or two Monday afternoon
across the San Juans, the start of the work week will be mainly
if not completely dry everywhere else. Given the dry air, expect
to see quite a bit more sunshine on Monday than we`ve had over
the past several days. The additional sunshine will also help to
boost high temperatures a few degrees higher than today and
closer to normal for this time of year.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 245 AM MDT Sun Mar 17 2024

The models still agree that the low pressure in the Desert
Southwest will finally start to kick eastward for good on
Tuesday. This is most likely due to the subtropical jet lifting
northward out of the equatorial region. This jet will shear the
low into an open wave as it slowly exits eastward. That track
will take it over Arizona and New Mexico. The most northern
portion of the system will brush the southern half of our
forecast area. With residual moisture in place and a some lift,
along with instability, we can expect showers for those
locations. A bulk of the QPF is in the mountains, but some of
that may reach the surrounding valleys. Snow amounts appear to
be fairly minor at this point. Temperatures will be on the rise
over the next few days and snow levels will follow suite. On
Wednesday the shortwave finally reaches the southern Plains, so
no more influence from that system. Although we will be left
with quite a bit of moisture so the chances for mountain showers
sticks around.

A ridge builds over the Desert Southwest on Thursday causing
northwest flow to become established over our region. This flow
brings a ribbon of moisture into the northern half of the
forecast area. It looks to be efficient enough for yet another
round of precipitation focused in the central and northern
mountains. Around this time we start to see highs in the 70s in
the Utah canyon country. Just about everybody will have highs
5-10 degrees above normal mid to late week.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1150 AM MDT Sun Mar 17 2024

SCT to BKN cloud deck is thinning out across the central areas
along and just south of the I-70 corridor as drier air works in
from the north, with clearing skies north of I-70. Expect
continued improvement in CIGS as well as sky coverage through
the day with mainly light, terrain driven winds and VFR
conditions across the northern and central areas. Showers will
be focused across the southern mountains and valleys today with
scattered coverage and brief MVFR and IFR conditions possible in
showers at KDRO and KTEX mainly. Winds will remain gusty this
afternoon at KVEL due to downsloping winds off the Uintas.
Showers are expected to diminish this evening and overnight as
drier air continues to move in from the north and shift the low
pressure system further south.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

UPDATE...DB
SHORT TERM...MDM
LONG TERM...KJS
AVIATION...MDA


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