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fxus65 kgjt 221730 

Area forecast discussion
National Weather Service Grand Junction Colorado
1130 am MDT sun Sep 22 2019

issued at 858 am MDT sun Sep 22 2019

Temperatures have risen above freezing in the lower elevations of
northwest Colorado. Therefore, have allowed the freeze warning for
the central Yampa river basin to expire.


Short term...(today through monday)
issued at 245 am MDT sun Sep 22 2019

Infrared satellite showing some high clouds along the Wyoming/Colorado border this
morning with little else across the County Warning Area. Plenty of radiational
cooling going on with many areas showing quite cool temperatures.
The freeze warning continues for the Yampa river basin where
observations show some spots hovering at or just below freezing.

For today, a transitory ridge moves through which will keep sunny
skies in the forecast. A weak jet streak will begin to move over
The Four Corners area this afternoon Onward and cause a few high
clouds to form but this shouldn't detract from the already nice
day taking place. Forecast skew-t's also show a weak mid-level
inversion setting up thanks to subsidence from the high pressure
so mixing will be limited today and thus, weaker surface winds.

By Monday morning, another trough will centered over Nevada as it
steadily drops southward. A jet streak on the western side of the
trough will continue to dig and eventually cause an area of low
pressure to form at the base of the trough. Once the low forms, an
already approaching slug of moisture will phase in with the low.
The precip then gets entrained into the cyclonic flow and will
follow the track of the low, which is to the south/southeast.
There's a slim chance that areas along the Colorado/nm border may see a
passing shower or storm and forecast reflects this thinking.
Wouldn't be surprised if we stay dry, however.

Long term...(monday night through saturday)
issued at 245 am MDT sun Sep 22 2019

Models are in very good agreement with the evolution of the area
of low pressure. Upper level support will cause the low pressure
to continue moving southward through Tuesday evening. At this
point, it'll be along the central Arizona/old Mexico border and then
becomes cutoff. The low will sit and spin in that general area
through Thursday until another system starts to drop down from the
Pacific northwest and forces it to get moving. Things get
interesting Friday onwards as the system may bring some precip to
our southern areas as it shifts to the plains. While this occurs,
the system that caused the cutoff low to move in the first place
will be moving into the western U.S. Bringing what looks like
widespread precip to just about every state to our west and north.
This system also looks like it may become cutoff but this is so
far out, am expecting some changes in the coming days.

For the most part, expect mostly sunny skies though the San Juans
south may see a bit more cloudiness thanks to the system that gets
cutoff in Arizona. Southwesterly flow ahead of the trough Monday
through Wednesday will bring above normal about
5 to 7 degrees...before dropping to normal Friday onwards. All
things considered, not bad for the first week of fall.


Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 1122 am MDT sun Sep 22 2019

VFR conditions should remain over the next 24 hours, with no
ceiling or visibility restrictions expected. Winds will also remain
light, with the exception of occasional wind gusts reaching 15-20 kt
possible for higher elevation taf sites this afternoon.


Gjt watches/warnings/advisories...


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