Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 281000

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
400 AM MDT Sun May 28 2017

.SHORT TERM...(Today through Monday)
Issued at 400 AM MDT Sun May 28 2017

A ridge of high pressure will build over the western US today and
bring mainly mostly sunny skies and seasonably cool temperatures
to the forecast area. A combination of residual moisture and
afternoon heating may allow a few showers and thunderstorms to
develop over the higher terrain, but expect these showers to be
short-lived and diminish by early evening. Clear and cool
conditions are expected on Sunday night. An uptick in moisture
from the south will result in isolated to scattered showers and
thunderstorms on Monday with the best focus along the higher
terrain near the Continental Divide. Seasonable temperatures are
expected on Monday.

.LONG TERM...(Monday night through Saturday)
Issued at 400 AM MDT Sun May 28 2017

An axis of high pressure will be just to our west Monday night and
will slowly drift eastward through much of the long-term period.
Usually, high pressure brings plenty of sunny skies and warm
temperatures but things will be a bit different this week.  As the
ridge stays to our west, a broad area of high pressure centered off
Florida will allow anti-cyclonic (read clockwise) winds to set up
over the Gulf of Mexico.  On the other side of the country a rather
deep trough will set up off the west coast which will allow cyclonic
(clockwise) winds to form.  These two wind flows will allow moisture
to stream in from the south, underneath the ridge axis bringing
precipitation to Mexico, New Mexico, and Colorado. As mentioned in
the previous long term discussion, this is what is meant when we
discuss a `dirty` high.

This moisture looks to start streaming Monday night and beyond and
is reflected in PWAT values reaching values between .6 and .7 inches
for much of the CWA which is quite above normal considering June is
usually one of our driest months.  Since the moisture is coming in
from the south, the San Juans will be favored.  We can expect
diurnally driven showers and storms each afternoon and evening with
an uptick Thursday and again Friday as the above mentioned west
coast trough moves overhead.

So the gist of next week is an increase in available moisture,
afternoon and evening showers and convection first favoring the San
Juans and higher terrain before becoming more widespread Thursday
and Friday.  Variable cloudiness looks to be the rule with more
clouds down south and over the higher terrain.  Some high clouds
will also drift over from time to time. Temperatures will hover
right around normal values, if not a few degrees higher.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 400 AM MDT Sun May 28 2017

Expect VFR conditions at all TAF sites. A few showers or
thunderstorms may develop over the higher terrain this afternoon
and diminish this evening.




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