Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 250009

Area Forecast Discussion
National Weather Service Grand Junction CO
609 PM MDT Mon Oct 24 2016

Issued at 356 PM MDT Mon Oct 24 2016

Showers and isolated storms forming further east than forecast
indicates so increased chances of pops late this afternoon through
the evening. Also, expanded the coverage a bit further east.


.SHORT TERM...(Tonight through Tuesday night)
Issued at 306 PM MDT Mon Oct 24 2016

The 12Z U/A H5 hand analysis is verifying the deep trough that
models have been advertising off the NOAM left coast. This led to
a long fetch of southwest flow from the subtropics into the Great
Basin. Derived satellite imagery and local RAOB reports are
indicating PWAT running 175-200 percent of (or 4 std dev above)
normal. This plume has been held to the west but is slowly
shifting eastward. Under this moisture band reported precipitation
rates have been 1 to 3 tenths per 6 hours with some isolated
amounts over half an inch. Snow levels out west at or above 10000
feet and figure this is a good indication of what to expect
tonight. Temperatures in the 10-11kft level have made it to the
upper 40s to lower 50s this afternoon and expect this event to
mainly be in the liquid form though some wet/low ratio snow is
definitely likely to fall over some of the mountain roadways. Do
not have enough confidence to issue winter headlines as impacts
appear to be minimal. The strong influx of moisture should also
help keep the more significant accumulations above timberline. We
should see precipitation blossom near the UT/CO border mid to
late evening as ascension in the moisture axis is enhanced by the
arrival of a coupled jet feature. Instability should also be
released by orographics and a mid level fronto feature. Isolated
thunderstorms will be possible through this time and could aid
some high precipitation rates and excess runoff is a possibility.
Snow level in the Western Colorado mountains will be rising
tomorrow morning as drier air works in from the west. Showers
should remain anchored over the hills through the afternoon but
the threat of accumulating snow will be ending. Temperatures will
be cooler behind the trough by some 7 to 12 degrees but still
ending up above normal.

.LONG TERM...(Wednesday through Monday)
Issued at 306 PM MDT Mon Oct 24 2016

Dry and warm conditions move back in for the mid week period as
the ridge rebounds back over the Intermountain West to the
Canadian Rockies. Once again the subtropical jet will usher in
moisture in the upstream portion of the ridge by Friday and an
ejecting wave will bring increasing cloudiness then scattered
precipitation Friday afternoon through Saturday. At the moment
however this system does not appear to be as organized or as moist
but will still be warm with high snow levels. The main piece of
the western trough will be forced inland by Sunday and is forecast
by models to mainly sweep across the northern states and only
brush our region with some lighter precipitation. There is a hint
that beyond this the weather pattern may become a bit more active
for the mid latitudes. Otherwise temperatures remain above
seasonable readings.


.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 603 PM MDT Mon Oct 24 2016

Cloud cover will continue to increase with showers moving in from
west to east across the area. Thunderstorms are possible as well
through 06z with VCTS at most TAF sites. Rain becomes more likely
and widespread by 06z with the best chance for wetting rain until
12z. Ceilings will lower close to or below ILS breakpoints at all
TAF sites with periods of MVFR vsby/cigs possible. Conditions
improve from west to east after 16z Tuesday with some lingering
showers over the higher terrain through early afternoon.




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