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377
FXUS65 KGJT 182311
AFDGJT

Area Forecast Discussion
National Weather Service Grand Junction CO
511 PM MDT Sun Apr 18 2021

.SHORT TERM...(Tonight through Monday night)
Issued at 232 PM MDT Sun Apr 18 2021

A pleasant day will turn into a tranquil night with cool overnight
lows expected. A few showers are possible near Wolf Creek Pass but
all in all, dry conditions are expected through tomorrow
afternoon. Tonight, clouds will be on the increase from north to
south ahead of a cold front that`s currently in Montana.

By Monday morning, the front will be over central Wyoming and as
it gets closer, the pressure gradient will start to tighten
causing an uptick in wind speeds. Debated on adding to the current wind
advisories for the I-70 corridor up to Eagle and also the
Montrose area but some discrepancies popped up. The EC ensembles
are very bullish in stronger winds for those areas while
statistical guidance...not so much. Forecast Skew-Ts do show some
midlevel clouds moving in and possibly cutting off any deeper
mixing...and thus weaker surface winds. A few more runs will help
so held off on expanding the wind advisory for now. The current
Red Flag Warnings remain in effect as described below. As far as
the front is concerned, it will move into the CWA between noon and
3PM and will bring valley showers (northern valleys), some
mountain snows (2 to 4 inches for Park Range), and a few rumbles
of thunder as it continues to push southward. Heavier precip will
shift to the central mountains around 9PM and by midnight, most
precip will be over aside from some precip over the San Juans.

.LONG TERM...(Tuesday through Sunday)
Issued at 232 PM MDT Sun Apr 18 2021

Dry northwest flow will prevail Tuesday in the wake of the departing
cold front with daytime highs sitting 10 to 15 degrees below normal
across the north and by 5 to 10 degrees further south. Tuesday will
also see the next Pacific wave trek along the west coast before
dropping into the Great Basin Tuesday night.
This system will slowly shift east throughout the day on Wednesday
resulting in a shift to westerly flow aloft over eastern Utah and
western Colorado. Even with the increase in clouds ahead of the
trough temperatures will warm by several degrees. Embedded moisture
in the flow may also initiate some orographic showers along the
Continental Divide Wednesday morning and early afternoon. Activity
will increase into the evening hours as the open wave lifts across
the region before sliding east of the Divide on Thursday. A
secondary weak wave will move through on Thursday night before the
base of a final trough extending south from Canada also passes
overhead late Friday. This unsettled pattern will lead to periods of
showers from mid to late week with the best coverage of showers
centered along the Divide. As has been the case with the last
several systems, any snow that falls will be confined to the highest
elevations with the majority of precipitation falling during the
daytime hours. As a result, impacts will be limited given the high
April sun angle. A ridge of high pressure will build overhead during
the weekend keeping conditions quiet and dry. The new work week
could be interesting as a strong low pressure system intensifies off
the west coast.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 508 PM MDT Sun Apr 18 2021

VFR conditions are expected tonight and tomorrow morning. A cold
front will drop southward through the northern sites tomorrow
afternoon. Showers may be possible along the front mainly across
northwest Colorado. Strong winds are expected at most sites
tomorrow afternoon.

&&

.FIRE WEATHER...
Issued at 232 PM MDT Sun Apr 18 2021

A strong cold front will move through Monday afternoon, favoring
showers over the northern and central mountains. Valleys will
remain dry with virga showers up north and windy conditions with
gusts to 40 mph or higher. This will result in critical fire
weather conditions for lower elevations of east- central to
southeast Utah and west-central to southwest Colorado tomorrow.
Strong winds and dry conditions across the Four Corners area may
persist well into next week.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Red Flag Warning from noon to 9 PM MDT Monday for COZ203-207-290-
     292-295.

     Wind Advisory from noon to 9 PM MDT Monday for COZ001-002-006.

UT...Red Flag Warning from noon to 9 PM MDT Monday for UTZ490-491.

     Wind Advisory from noon to 9 PM MDT Monday for UTZ024-027.

&&

$$

SHORT TERM...TGR
LONG TERM...MMS
AVIATION...TGJT
FIRE WEATHER...TGJT