Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 191650

Area Forecast Discussion
National Weather Service Grand Junction CO
1050 AM MDT MON SEP 19 2016

.SHORT TERM...(Today through Tuesday)
Issued at 255 AM MDT Mon Sep 19 2016

Another beautiful day in store as high pressure remains in
control. A few clouds are possible over the higher terrain but, by
and large, clear skies will be the rule with some gusty afternoon
winds though nothing out of the ordinary. Southwest to westerly
wind will keep warm air in the picture with afternoon high temps
reaching about 10 degrees above normal for most areas. A pleasant
evening and night are also expected.

On Tuesday, moisture from TS Paine off the Baja coast will get
caught in the anticyclonic flow from the high pressure over Texas
and start streaming into our area. We`ll start seeing this as high
clouds start to move into the four corners region Monday evening
into the overnight. By Tuesday morning, high clouds will be
prevalent from about the I-70 corridor south with precipitation
chances increasing Tuesday afternoon onwards.

Interestingly, the GFS was really quite aggressive bringing
precipitation to mainly southern areas of the CWA starting Tuesday
morning. The NAM was having none of it though and really kept
rain chances at a minimum. The ECMWF was somewhere in between. It
now appears that the NAM was correct as both the GFS and ECMWF
have followed the NAMs lead and started doing two things: 1.
Slowing down the onset of precipitation and 2. Lowering QPF
amounts while coverage only now looks to be in the San Juans and
areas on their periphery. Will be interesting to see what the next
few model runs bring!

.LONG TERM...(Tuesday night through Sunday)
Issued at 251 PM MDT Sun Sep 18 2016

Isolated showers and thunderstorms will develop by Tuesday
afternoon and spread northeast increasing in coverage by Tuesday
night. At the onset, gusty outflow winds will be the main impact.
However, locally heavy rain will be possible with the stronger
storms Tuesday night into Wednesday, mainly over the southern half
of the forecast area. By late Wednesday, a strong storm system
will be over the Pacific northwest. This system will move into the
Great Basin region by Thursday and is forecasted to eject
northeast through Wyoming on Friday. Expect southwest flow to
increase ahead of this system late Wednesday into Thursday with
showers and thunderstorms increasing in coverage through Thursday
night. Colder air will move across the area by Friday morning
lowering snow levels to between 8000 and 9000 feet as
precipitation coverage becomes more confined to the higher
elevations and the northern portions of the forecast area late
Friday into Saturday. Drier northwest flow will return on Sunday.
Temperatures are expected to be seasonable through mid-week with
much colder temperatures expected by late in the week.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1050 AM MDT Mon Sep 19 2016

VFR conditions will continue through the next 24 hours. After
midnight tonight clouds will begin to increase from the south and
spread over the area through the morning. Clouds will thicken by
late morning but bases will still remain at the mid levels and
above. Generally light southwest to west winds are expected.


.GJT Watches/Warnings/Advisories...


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