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Area forecast discussion 
National Weather Service Grand Junction Colorado
318 PM MDT Thursday Apr 17 2014

Short term...(this evening through Friday night)
issued at 121 PM MDT Thursday Apr 17 2014

High pressure passes over the forecast area tonight giving way to
dual Pacific systems coming onshore Friday morning. The northern
system in the Pacific northwest will track through the northern rockies
providing some weak upper level support. The more important low
approaches from the SW transporting significant moisture. Friday
forecast soundings show inverted v profiles with enough cape to
justify a mention of afternoon-early evening thunderstorms. Precipitation
water values surge from 0.3 inches to 0.6 inches into the
southern valleys overnight. The top-down filling of the inverted v
profile often leads to gusty winds and have added scattered
nighttime probability of precipitation with wind gusts to 25 miles per hour. There is some potential
for stronger gusts and more widespread showers. Snow levels around
10kft Friday afternoon drop to around 8kft overnight. A few inches
of accumulation are possible in the southern mountains overnight.

Long term...(saturday through thursday)
issued at 121 PM MDT Thursday Apr 17 2014

Expect a dreary start to the weekend with a swath of subtropical
moisture over the region on Saturday producing mostly overcast
skies and scattered showers. These showers will spread from
southwest to northeast throughout the day and be aided in growth
by topography and daytime heating in the afternoon. The NAM model
is parched on its precipitation coverage forecast which keeps
precipitation over southwest Colorado and along the central mountains rather
than the GFS/ec solution which brings a widespread area of showers
from The Four Corners northeast to the Flattop mountains most of
northwest Colorado and northeast Utah looks to stay out of the bulk of
precipitation on Saturday but there could still be a few isolated
showers around. The chance for thunderstorms exists on Saturday but with
no jet aloft to sustain updrafts and little dynamics except for a
weakening trough passage...not overly excited about this

Weak ridging builds in again on Sunday but as weak disturbances
pass through the clockwise flow through early next week...a few
isolated afternoon showers over higher terrain are expected.

Tuesday will be the driest day in the long term period...albeit
quite windy. Sustained southwest winds of 30 to 40 miles per hour are
probable on Tuesday with wind gusts up to 55 miles per hour. Just 24 hours
ago we were looking at a potentially moist and cold system diving
into the area on Wednesday/Thursday but the latest model runs have moved
this system to our north with precipitation impacts minimal and
localized to the north and occurring on Thursday instead. With
such inconsistency...forecast past Tuesday is low confidence.


Aviation...(for the 00z tafs through 00z Friday evening)
issued at 121 PM MDT Thursday Apr 17 2014

VFR conditions dominate through noon Friday. Thereafter isolated
to scattered showers and thunderstorms will begin to develop
favoring the southern mountains. Local circumnavigable showers and
thunderstorms are expected after 21z mainly over the mountains.
Local mountain tops obscured in heavier showers. Gusty outflow winds
and resulting turbulence are possible near any afternoon


Fire weather...
issued at 121 PM MDT Thursday Apr 17 2014

Critical fire weather conditions are possible on Tuesday and
Wednesday across eastern Utah and much of western Colorado.
Sustained southwest winds of 30 to 40 miles per hour are probable on Tuesday
and potentially into Wednesday with wind gusts up to 50 miles per hour. The
highest threat is near the 4 corners and in eastern Utah where
fuels are dry. Relative humidity values are expected to be between
10 and 20% at locations below 8000 feet. Will be keeping an eye
on the possibility of this wind/low relative humidity event.


Gjt watches/warnings/advisories...


Short term...Joe
long term...jam
fire weather...jam