Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 201136
AFDGJT

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
436 AM MST Sat Jan 20 2018

.SHORT TERM...(Today through Sunday)
Issued at 436 AM MST Sat Jan 20 2018

Very little change to forecast thinking as models remain fairly
consistent. The front remains to our west, running from north of
Salt Lake City southwestward to south central Nevada. Satellite
clearly showing a baroclinic leaf over Utah and Arizona while our
radar has started picking up on some higher clouds. Some snow can
be seen over the Uintas at this hour so the warning for that area
looks to be on track. For the rest of today, strong southwesterly
flow will continue to keep warm temperatures in place. The cold
front will be just west of the Colorado/Utah border towards the
evening hours so expect rain for the valleys through the day with
snow above 8 to 8.5K feet (maybe a bit higher). As has been noted
over the last few days, the front has slowed down which has also
slowed down the onset of precipitation. Things will get going from
about 2PM onwards with the heaviest rain/snow to occur from the
early evening hours to early Sunday morning. Current advisories
and amounts look good, though might need to add zone 2 (Craig,
Meeker) later this evening for a quick 2 to 3 inches of snow
though confidence just not there at the moment to issue anything
right now. Later shifts can keep an eye on temps and evolution of
the front. Once the cold front moves through, temperatures will
start dropping and snow levels will reach valley floors. Central
and southern valleys may see some light snow accumulation, around
an inch, though higher elevations along 160 west of Durango
towards Mancos may see higher amounts as they tend to do.

By daybreak Sunday morning, colder air will continue to move in
causing plenty of showers across the entire forecast area. By
about noon these should wane except along the Continental Divide
where they should continue for through the afternoon. Outside of
the showers, expect a mostly cloudy day with cooler temperatures
across the region.

.LONG TERM...(Sunday night through Friday)
Issued at 436 AM MST Sat Jan 20 2018

A few snow showers will linger near the Divide Sunday evening as
the main upper level low pulls out into the plains, being
replaced by short-wave ridging sliding over from the west. Ridge
flattens out Monday afternoon with just enough mid-level moisture
dragging along to help squeeze out a few showers across the
northern mountains in favorable orographics. Weak wave enhances
the potential for snow showers Monday night and Tuesday with focus
on the northern mountains once again, generally from Vail Pass
northward to the Wyoming state line. This system has been trending
weaker over the past several model runs and will keep
accumulations on the low side for now. Remainder of the forecast
area will be on the dry side for much of the week as another
transitory ridge slides over around mid-week. Pattern breaks again
by late in the week with a stronger longwave trough moving
onshore. This system will arrive over our region late Thursday and
Friday, bringing more widespread and welcomed rain and snow.
Expect a much cooler weak in the temperature department as we see
readings dropping back to more normal values for this time of the
year.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 436 AM MST Sat Jan 20 2018

Clouds will continue to increase, thicken and lower as the day
moves forward. By 16Z, BKN clouds with bases near 5K feet are
expected north of the I-70 corridor but will not move much further
south until the front moves through. KVEL will be affected with
these lower ceilings dropping to MVFR at times. KGJT, KRIL, and
KEGE might see ILS breakpoints reached from 17Z onwards but they
may also just be on the fringe of these lower ceilings. The lower
clouds and ceilings won`t affect remaining TAF sites until the
front moves through later this afternoon between 21z to 00Z. As
this occurs, ILS breakpoints will be reached for all TAF sites as
will MVFR under rain and snowshowers. Lower ceilings and
visibilities can be expected through the overnight hours.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...Winter Weather Advisory from 2 PM this afternoon to 2 PM MST
     Sunday for COZ003-009-012-017>019.

     Winter Weather Advisory from 6 PM this evening to 9 PM MST
     Sunday for COZ004-010-013.

     Winter Weather Advisory from 6 PM this evening to 10 AM MST
     Sunday for COZ001.

UT...Winter Weather Advisory from 10 AM this morning to 10 AM MST
     Sunday for UTZ025-028.

     Winter Storm Warning until 6 AM MST Sunday for UTZ023.

&&

$$

SHORT TERM...TGR
LONG TERM...JDC
AVIATION...TGR



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