Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 211742

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
1042 AM MST Tue Nov 21 2017

.SHORT TERM...(Today through Wednesday)
Issued at 343 AM MST Tue Nov 21 2017

Moisture flowing the down the back side of the western ridge has
led to orographic showers over the northern to central mountains
early this morning. The main piece of energy in the flow is
dropping across the Wyoming Rockies here in the pre-dawn hours
and is adding a bit of a convective twist to the snow and will
continue to do so through mid morning. Dry low layers of the
atmosphere proving hard to saturate with out strong large scale
ascent and so far but the convection may help this a bit. Heaviest
snow will still be impacting the Park...Gore and Flat Top ranges
down to the Vail Pass area through about noon. After this much
drier air invades aloft and erodes the moisture out of the
dendritic layer and besides some high peak flurries we should be
done and hopefully improved travel conditions can get back on
track. Dirty flow on the downstream side of the ridge continues
into Wednesday and models want to keep some light precipitation
over the northern mountains. Again saturation is suspect and do
not anticipated any significant impacts except for some passing
flurries. My temperature forecasts have been suspect as well in
many valley locations by underestimating the inversions. Clouds
didn`t help on Monday either. Today appears to be a bit more sunny
with some mixing albeit weak. Have trended temperatures down in
valleys to lower end of guidance or less. Overall however there
should be a warming trend starting today and persisting through
the week.

.LONG TERM...(Wednesday night through Monday)
Issued at 343 AM MST Tue Nov 21 2017

A large area of high pressure centered just west of the Baja
Peninsula will be the dominant weather feature in the long term
period. Plenty of moisture and energy will affect the Pacific
northwest but this energy will ride up and over the ridge keeping
us generally dry through the period. On Friday, a weak wave will
dive down from the northwest and may bring a few showers/sprinkles
to our far northern zones and Park/Gore ranges but really, nothing
of any great import expected. The high pressure remains in
control through the weekend before breaking down as a stronger
trough moves through on Monday. Model guidance showing a bit wider
spread of precipitation but again, qpf remains on the low side. As
one would expect under high pressure, warm temperatures will make
a return reaching well above normal for this time of year for the
entire long term period. High clouds will also be common for much
of the area.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1042 AM MST Tue Nov 21 2017

Some light snow showers will continue to impact the divide
mountains and passes of northwest Colorado with ASE and EGE TAF
sites seeing lower ceilings reaching ILS breakpoints at times due
to cloud cover. Conditions will improve after 21Z as drier air
moves in from the west, resulting in VFR conditions area wide with
light terrain driven winds. Some mountain turbulence is still
possible through this evening with stronger winds aloft as the
upper level jet remains overhead.




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