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 44 45 46 47 48 49 50
369
FXUS65 KGJT 240531
AFDGJT

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
1131 PM MDT Sun Apr 23 2017

Updated aviation discussion

.UPDATE...
Issued at 810 PM MDT Sun Apr 23 2017

Updated to remove expired Red Flag Warning headlines.

UPDATE Issued at 443 PM MDT Sun Apr 23 2017

Decreased the areal coverage of precipitation this evening across
the area. Satellite and observations show only mid and hi cloud
and no precipitation with the initial push from the approaching
trough. Precipitation should increase starting around midnight.

.SHORT TERM...(Tonight through Monday night)
Issued at 342 PM MDT Sun Apr 23 2017

Plenty of clouds streaming across western Colorado and eastern
Utah this afternoon ahead of an approaching disturbance along with
some breezy conditions. This shortwave will quickly trek across
the region this evening with the bulk of moisture and lift
tracking north. Snow levels will generally remain between 8,000
and 10,000 feet with just a few tenths of snow falling for the
northern mountains through early Monday.

The progressive weather pattern really kicks off Monday evening as
a broad, positively-tilted upper level trough and associated cold
front begin to impact the area. Southwesterly flow will increase
ahead of this storm Monday afternoon and, even though sustained
speeds of 20 mph are possible in the Four Corners region, do not
anticipate any widespread critical fire weather conditions for
Monday. See the Fire Weather section below for more details.

As far as precipitation goes, orographic showers will progress
south by late afternoon and become quite numerous along the
Continental Divide Monday night. A few thunderstorms are not out
of the question either but CAPE values remain unimpressive.
Precipitable water, however, is a different story as it peaks on
Monday night with amounts ranging from 0.50 to 0.65 inches which
is close to double the climatological normal for this time of
year. Snow levels will remain high at the beginning of this storm
with the colder air not arriving until Tuesday. More on that
below in the Long Term Discussion.

Overnight lows tonight will generally be several degrees warmer
as a result of increased cloud cover. Consequently, highs Monday
will be cooler in response to clouds and showers.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 PM MDT Sun Apr 23 2017

Numerous showers will persist on Tuesday with the base of the
trough forecast to swing through the area Tuesday evening.
Moisture remains impressive during the latter half of the storm
and, once that cooler air moves in, snow levels will drop down to
between 6,000 and 7,000 feet. Storm total snowfall for mountain
areas above 10,000 feet looks to be around 4 and 8 inches. Seeing
as how much of the precipitation looks to fall Tuesday afternoon
and early evening, impacts to travel will be minimal. However,
slick conditions could develop during the overnight hours so as
always, use caution while driving over those higher mountain
passes.

Unsettled northwesterly flow sets up behind the trough as it moves
east, allowing for orographic showers to linger on Wednesday
morning and afternoon. The next storm is set to impact the region
as early as Wednesday night as a Pacific trough digs inland. Extended
models are already starting to differ in terms of intensity and
timing with the GFS being much more bullish than the Euro. Behind
the midweek storm, yet another low looks to track through the
Great Basin for the weekend but, given how far out into the
extended it is, will keep PoPs on the conservative side and
patiently wait for the models to come into a better consensus!

A cooling trend will persist throughout the week with many lower
valley locations dropping back into the mid and upper 50`s by
Thursday. Subfreezing temperatures will be possible for some
valley areas towards the latter half of the week so that will be
something else to monitor in the coming shifts.

&&

.SHORT TERM...(Tonight through Monday night)
Issued at 342 PM MDT Sun Apr 23 2017

Plenty of clouds streaming across western Colorado and eastern
Utah this afternoon ahead of an approaching disturbance along with
some breezy conditions. This shortwave will quickly trek across
the region this evening with the bulk of moisture and lift
tracking north. Snow levels will generally remain between 8,000
and 10,000 feet with just a few tenths of snow falling for the
northern mountains through early Monday.

The progressive weather pattern really kicks off Monday evening as
a broad, positively-tilted upper level trough and associated cold
front begin to impact the area. Southwesterly flow will increase
ahead of this storm Monday afternoon and, even though sustained
speeds of 20 mph are possible in the Four Corners region, do not
anticipate any widespread critical fire weather conditions for
Monday. See the Fire Weather section below for more details.

As far as precipitation goes, orographic showers will progress
south by late afternoon and become quite numerous along the
Continental Divide Monday night. A few thunderstorms are not out
of the question either but CAPE values remain unimpressive.
Precipitable water, however, is a different story as it peaks on
Monday night with amounts ranging from 0.50 to 0.65 inches which
is close to double the climatological normal for this time of
year. Snow levels will remain high at the beginning of this storm
with the colder air not arriving until Tuesday. More on that
below in the Long Term Discussion.

Overnight lows tonight will generally be several degrees warmer
as a result of increased cloud cover. Consequently, highs Monday
will be cooler in response to clouds and showers.

.LONG TERM...(Tuesday through Sunday)
Issued at 342 PM MDT Sun Apr 23 2017

Numerous showers will persist on Tuesday with the base of the
trough forecast to swing through the area Tuesday evening.
Moisture remains impressive during the latter half of the storm
and, once that cooler air moves in, snow levels will drop down to
between 6,000 and 7,000 feet. Storm total snowfall for mountain
areas above 10,000 feet looks to be around 4 and 8 inches. Seeing
as how much of the precipitation looks to fall Tuesday afternoon
and early evening, impacts to travel will be minimal. However,
slick conditions could develop during the overnight hours so as
always, use caution while driving over those higher mountain
passes.

Unsettled northwesterly flow sets up behind the trough as it moves
east, allowing for orographic showers to linger on Wednesday
morning and afternoon. The next storm is set to impact the region
as early as Wednesday night as a Pacific trough digs inland. Extended
models are already starting to differ in terms of intensity and
timing with the GFS being much more bullish than the Euro. Behind
the midweek storm, yet another low looks to track through the
Great Basin for the weekend but, given how far out into the
extended it is, will keep PoPs on the conservative side and
patiently wait for the models to come into a better consensus!

A cooling trend will persist throughout the week with many lower
valley locations dropping back into the mid and upper 50`s by
Thursday. Subfreezing temperatures will be possible for some
valley areas towards the latter half of the week so that will be
something else to monitor in the coming shifts.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1131 PM MDT Sun Apr 23 2017

Weak disturbance passing through NE Utah and NW Colorado overnight
tonight will bring vcsh and -ra to KVEL through about 08z before
conditions begin to clear from the west. These showers will trek
eastward through 12z before crossing the Continental Divide
completely. The next weather system is rapidly approaching from
the west and will increase mid to high level clouds across the
region early Monday morning. By 00z or shortly thereafter, showers
will begin to impact TAF sites, with the mountain sites most
likely to see some ILS breakpoints reached during shower activity.


&&

.FIRE WEATHER...
Issued at 342 PM MDT Sun Apr 23 2017

Red Flag Warning expired for zones 203, 207, 290 and 292. Winds
decreased and humidity increased with sunset.

Going into the new work week, a series of storms will impact
eastern Utah and western Colorado through much of the week
resulting in extended periods of cooler and then wetter
conditions. Southwesterly flow will increase ahead of each storm
but excessive cloud cover should be enough to keep humidities
above critical fire weather thresholds. However, isolated pockets
of lower humidities and gusty winds are possible Monday afternoon
in the southern valleys.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

$$

UPDATE...CC
SHORT TERM...MMS
LONG TERM...MMS
AVIATION...JAM
FIRE WEATHER...MMS/CC



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