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Area forecast discussion 
National Weather Service Grand Junction Colorado
528 am MDT Wednesday Jul 23 2014

Short term...(today through thursday)
issued at 355 am MDT Wednesday Jul 23 2014

Moisture surge from the south is underway. Nocturnal showers and
isolated storms appear to have ended over parts of SW Colorado
early this morning. Moisture will continue to stream north today
and encompass much of the forecast area. With the high core
located over Colorado...strong surface heating will not be a
problem and will be the primary trigger mechanism...but colliding
outflow boundaries could be a secondary trigger mechanism. High
cloud bases with the sub cloud environment remaining relatively
dry will be ideal for gusty outflow winds. Most cells will remain
anchored over the high terrain...but colliding boundaries could
spawn a few cells over valley spots late in the day.

While we should see showers and thunderstorms diminish later this
evening as daytime heating shuts off...some activity will persist
overnight due to the continued subtropical moisture streaming
into the forecast area from the south. The south will be favored
as the NAM shows precipitable water values peaking at 1.25 inches
near The Four Corners before sunrise Thursday.

The high pressure ridge will begin to be flattened on Thursday as low
pressure moves east-northeast out of the Pacific northwest.
However the flow will remain southwest over our forecast area
through midday at least...and will continue to carry moisture from
the subtropical surge across western Colorado and eastern Utah.
Precipitable water values will remain between 0.75 and 1.0 inch
through the day...with some drying possible over the far
northwest corner late in the afternoon. Therefore we can expect
to see another healthy round of daytime showers and thunderstorms.

Long term...(thursday night through tuesday)
issued at 355 am MDT Wednesday Jul 23 2014

The flow will become more westerly Thursday night and on Friday as the
northern low moves across southern Saskatchewan. This will bring
some drier air over the region. We should see a moisture gradient
from south to north...with precipitable water values staying near
an inch in The Four Corners area through Friday. Expect that Friday
will not be as convectively active...especially in the north. This
westerly flow will increase in speed over the northern portion of
the area...with increased winds at the surface Friday afternoon.

Saturday through Tuesday...diurnally driven storms with the deepest
moist layer over southwest Colorado is the dominant weather
pattern. The GFS and European model (ecmwf) models show an amplified ridge centered
over Utah later this weekend into Monday and Tuesday. Not exactly
an ideal setup for monsoonal moisture to stream into The Four
Corners region. But moisture will be circulating around the high
pressure system to fuel convective storms. Steering winds will be storms will be anchored to the high terrain early
on...then outflow boundaries will dictate new storm development.


Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 528 am MDT Wednesday Jul 23 2014

Scattered -tsra will develop after 17z this morning and increase
into early evening. Strong outflow winds in the 30-40kt range will
be possible from thunderstorms. Local obscurations and MVFR ceilings
may occur over the San Juan Mountains. Scattered showers and
thunderstorms will continue through the evening but decrease in
areal coverage after 04z...but isolated activity may linger
through 12z Thursday morning.


Fire weather...
issued at 355 am MDT Wednesday Jul 23 2014

Deep mixed layer will result in locally breezy winds. With low
humiditiy...conditions will be approaching critical fire weather
conditions...especially near the Wyoming border. Appears this
critical conditions are localized and will not hoist any red flag
warnings at this time.


Gjt watches/warnings/advisories...



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