Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 122341

Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
541 PM MDT Mon Mar 12 2018

.SHORT TERM...(Tonight through Tuesday night)
Issued at 355 PM MDT Mon Mar 12 2018

Some light isolated showers will linger over the Continental
Divide early this evening, otherwise expect dry conditions and
decreasing clouds overnight. Diurnal warming combined with modest
moisture and a weak disturbance in northwest flow is expected to
yield isolated showers over the higher elevations of the San Juan
Mountains Tuesday afternoon. This activity will linger into the
early evening. Elsewhere on Tuesday, expect mostly sunny skies and
mild temperatures. Highs will be running on the order of 10
degrees above normal. The remainder of Tuesday night will be dry
with cirrus beginning to spill over eastern Utah and western
Colorado ahead of a low pressure trough over the West Coast.

.LONG TERM...(Wednesday through Monday)
Issued at 355 PM MDT Mon Mar 12 2018

Look for warm and windy weather on Wednesday as a short-wave
trough ejected from a closed low over the West Coast sweeps
across the Great Basin driving a cold front toward the forecast
area. Strong and gusty southwest winds will help drive
temperatures to their warmest levels so far this year. Current
guidance indicates winds will be below advisory criteria on the
whole, but virga and isolated showers may drive winds to 45 MPH or
more during the afternoon, mainly across northeast Utah.

Models indicated the trough and its associated front will plow
through the region Wednesday night bringing the likelihood of rain
and snow to the region. Snow levels will start at close to 9500
feet before lowering to near mountain bases by Thursday morning
and this will play against significant accumulations. Current
forecast calls for roughly 3 to 6 inches of new snow above 9000
feet with significantly lighter accumulations at 8000 feet.

Model consensus was poor beyond Wednesday as the ECMWF and
Canadian favored a strong secondary shortwave moving across the
area Thursday and Thursday night, lingering into Friday. The GFS
and NAM solutions depicted a shallower, faster moving trough
generating scattered shower activity Thursday, then drying
Thursday night and Friday. GFS depicts what could be a more
impactful winter storm this weekend, while the ECMWF solution was
about 12 hours slower and significantly weaker. Seems reasonable
to expect unsettled conditions this weekend, but attempting to
specify the magnitude and impacts of this activity given model
differences would be unwise.

Expect temperatures to be cooler Thursday in the post-frontal
environment left behind by the first system, where they`ll stay
during the remainder of the week. Though cooler, these
temperatures will still be above normal for this time of year.
However, colder than normal readings are possible Sunday and


.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 540 PM MDT Mon Mar 12 2018

Mid and high level cloudiness will continue to drift east
southeast across the area this evening with clearing conditions
anticipated after 03Z. There is a less than 10 percent chance for
isolated, high-based convective showers across the central
mountains in western Colorado. Gusty outflow winds to around 25
kts will be the main concern as little to no significant
precipitation is expected to reach the ground. CIGS may drop to
ILS breakpoints east of a line from KCAG-KEGE-KGUC this evening,
otherwise VFR conditions should be expected at all sites through
Tuesday evening.




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