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National Weather Service Grand Junction Colorado
540 PM MDT Tuesday Sep 16 2014

Short term...(tonight through Wednesday night)
issued at 331 PM MDT Tuesday Sep 16 2014

Dry condition today through the next 36 hours with kgjt precipitable water at
0.66 inches and little change predicted. Just enough moisture and
good surface heating allowed scattered cumulus and isolated
showers and thunderstorms to form over most mountains and these
should dissipate after sunset.

Odile was moving onshore over northwest Mexico and appears will pass south
of the Colorado and Utah Wednesday and Thursday. A band of middle and high cloud north
of Odile is ridging north from nm and Arizona and will slowly spread
across SW Colorado and southeast Utah tonight and Wednesday.

A large ridge is the main weather feature over the western U.S.
And this will propagate east tonight through Wednesday night. The 500
mb Ridgeline should be over the Colorado and Utah border about 00z Thursday and
reach central Colorado by Thursday 12z. The SW flow west of the Ridgeline
will allow subtropical moisture to begin moving north over Utah and
Colorado Wednesday and Wednesday night. Have increased clouds over the southern
quarter of the area for the middle and high cloud edging north from
Arizona and nm...while decreasing cloud cover in the grids over the
rest of the forecast area due to dry and subsident conditions.

Long term...(thursday through tuesday)
issued at 331 PM MDT Tuesday Sep 16 2014

Confidence was shattered earlier this week as middle to late term
models were inconsistent in both continuity and timing in dealing
with Odile and the push inland of a West Coast trough. Today things
are looking more peachy as both aspects have improved considerably
over the past 24 hours. It now appears Odile will be undercutting
the Ridge...Crossing the Desert Southwest...and forming a Rex type
pattern over the Great Basin and Colorado rockies. This does not
Bode well for pulling a strong amount of moisture northward or
spreading significant large scale ascent across our County Warning Area. Precipitable water that
was well over an inch a few days ago are now running near three
quarters of an inch. Can this change or model agreement flip
again...yes...but for now have to trend probability of precipitation and especially quantitative precipitation forecast
downward with this consensus. There will still be the diurnal
convection as moisture will not be completely gone but coverage appears
limited. Middle level dynamics become slightly enhanced late Thursday
into Friday as the West Coast trough will be catching the
westerlies. The problem here is the trough is phased as it moves
inland but by Friday morning is showing signs of splitting. In
fact by 24 hours later another Rex pattern will be setting up in
the west as models do close a low off the central California coast
with strong ridging to the north. This scenario should lead to a
quiet weekend with moisture surging back into the region early
next week as low out west progresses into the western Great Basin.
Not holding onto my hat on any solution with model consensus of
late...but probability of precipitation were gradually increased in the blended solutions
and did not make changes. Temperatures on Thursday will be warm
with less mositure around...the remainder of the forecast looks to
be seasonal.

&&

Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 540 PM MDT Tuesday Sep 16 2014

Isolated -tsra/-shra will linger until sunset...otherwise no
aviation hazards expected overnight. After 19z Wednesday...
isolated -tsra can be expected for SW Colorado. Only a few or
scattered clouds are expected elsewhere.

&&

Gjt watches/warnings/advisories...
Colorado...none.
Utah...none.
&&

$$

Short term...cirrocumulus
long term...15
aviation...pf

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