Area Forecast Discussion
Issued by NWS Grand Junction, CO
FXUS65 KGJT 151707
Area Forecast Discussion
National Weather Service Grand Junction CO
1107 AM MDT Sat Oct 15 2016
.SHORT TERM...(Today through Sunday)
Issued at 242 AM MDT Sat Oct 15 2016
High clouds associated with abundant Pacific moisture continue to
pass over the forecast area this morning. These clouds should
scatter out later this afternoon as the jet stream pushes to the
north. At the surface southwesterly winds will persist today and
become gusty this afternoon with the heating of the day inducing
The 0000Z ECMWF and GFS20 have initialized well with the current
synoptic weather pattern and remain in good agreement through
Sunday. Both models predict fair weather through Sunday with
slightly above normal temperatures. High clouds will be on the
increase Sunday ahead of an approaching trough of low pressure.
.LONG TERM...(Sunday through Friday)
Issued at 335 PM MDT Fri Oct 14 2016
Going into the latter half of the weekend and into early next week,
yet another upper level trough will dig into the Pacific Northwest.
The bulk of moisture ahead of this feature will brush our northern
counties beginning Sunday night. An associated cold front will push
through the forecast area on Monday and bring a decent chance for
precipitation to our northern and central mountains.
A secondary shortwave will impact the area Tuesday night and Wednesday.
700mb temperatures are around -4 to -6 degrees C, dropping snow
levels to at or around 9000 feet for the northern mountains. The
GFS shows greater impact, bringing the disturbance right through
the forecast area while the ECMWF has a more conservative track
with less moisture. Am favoring the latter model and restricting
higher POPs to over the northwest Colorado mountains for the
moment. Behind this feature, drier northwesterly flow sets up over
the region on Thursday as a ridge of high pressure builds west of
the forecast area.
Temperatures will drop back to near seasonal levels on Monday night
into Tuesday behind the cold front. However, daytime highs will
quickly rebound back to normal by the end of the work week as the
ridge of high pressure keeps conditions high and dry. Overnight lows
will remain on the cool side under clear skies.
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1107 AM MDT Sat Oct 15 2016
VFR conditions and CIGS above ILS breakpoints will prevail through
the next 24 hours as a dry stable atmosphere remains in place.
Meanwhile, atmospheric mixing deepens in response to rising
temperatures which will wipe out LLWS at mountain TAF sites prior
to 18Z. However, deep mixing will bring breezy southwest winds to
all TAF sites through 01Z/Sunday. Decreased winds after 01Z will
shift to normal drainage flows by 06Z which will persist into
Sunday morning. LLWS will become an issue once again for most TAF
sites later tonight.