Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 181738

Area Forecast Discussion
National Weather Service Grand Junction CO
1038 AM MST Sat Jan 18 2020

.SHORT TERM...(Today through Sunday)
Issued at 238 AM MST Sat Jan 18 2020

A dirty ridge of high pressure will amplify over the Great Basin
today with dry northwesterly flow persisting across eastern Utah
and western Colorado. This will result in benign conditions with
passing high and some mid-level clouds. 700mb temperatures of -4
to -10 degrees C will settle overhead in the wake of yesterday`s
trough, resulting in daytime highs some 4 to 8 degrees cooler, but
even less so across the southern valleys. The good news is,
looking at Bufkit soundings for those lower valleys that saw snow
yesterday (Durango, Pagosa Springs, Moab), there is no indication
that any inversions will set up! While the upper level gradient
will relax today as the jet exits to the east, 250mb winds remain
between 55 and 65 knots across the region, allowing for
occasionally breezy conditions and good mixing which will inhibit
said inversions from forming. Another quiet night is on tap for
tonight with overnight lows sitting near or slightly below
seasonal normals under mostly clear skies. The high will continue
to build on Sunday allowing the dry and quiet weather to persist.
Daytime highs will moderate a few degrees.

.LONG TERM...(Sunday night through Friday)
Issued at 238 AM MST Sat Jan 18 2020

Sunday night will see the 700mb high pressure circulation drift
east across the Western Slope. The ridge axis will pass over the
Northern Rockies Monday morning before quickly sliding east into
the Northern Great Plains by Monday evening as a weak midlevel
trough approaches from the west. This shallow feature will
generally just bring increased clouds to eastern Utah and western
Colorado on Monday and a quick shot of precipitation to the region
on Tuesday, favoring the Continental Divide. Discrepancies
continue to plague the extended forecast models in regards to the
next Pacific trough set to impact the region at the midweek point.
The Euro is the outlier at the moment as it brings this system
into our area Tuesday night, splitting the flow with one wave
impacting the far Northern Rockies while the other tracks south
across the southern Colorado mountains. The GFS and Canadian favor
a slower, more northerly solution that arrives as a closed low
Wednesday afternoon. Regardless, despite model differences, the
pattern looks unsettled late Tuesday into Wednesday, with dry
weather overall returning Thursday afternoon through the coming
weekend. After warming back to seasonal normals early in the week,
expect temperatures to drop back to below normal in response to
increased clouds and showers with the midweek storm.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1032 AM MST Sat Jan 18 2020

Mid to high level clouds will cross the region this afternoon as a
ridge of high pressure builds to our west. No precipitation and
light winds are anticipated across all sites for the entire TAF
period. Locations along and just south of the I-70 corridor (i.e.
KRIL, KEGE, and KASE) may hover over ILS breakpoints as clouds
pass from west to east through this evening. Otherwise, remaining
sites will see prevailing VFR conditions for the next 24 hours.




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